Programming volatile memory boards in older Icom Rigs and radio upgrades - Page 1
Forum section: electronics / rf-microwave

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 10, 2017, 04:40:27 pm
content: Hello all.Some of the older Icom HF radios use a RAM board that holds the factory memory like the IC-745 and IC-751. When the battery goes dead on these boards the factory program is lost and your radio becomes a brick. The battery has a life of about 7 years but can be changed out. If not done correctly you lose the memory, again you end up with a brick.A few folks have made a non volatile replacement board to solve this problem. Cost around 70 bucks US or so. Not bad no?Anyway years ago I was able to read the memory out of one of these boards for the IC-745, This was by using the N2CBU DIY programmer. This was a dos base programmer that using the parallel port on you old pc. The programmer uses a CD4040, a 7805 regulator and a couple of caps. It worked OK for reading the content of the ram. I never tried programming the unit.What this is all about?I am not the best when it comes to designing programmers. But I like to build something that is modern to work with today's computers. I like to build a programmer that would be able to plug into a usb port, read the content of the ram then save it. And the ability to send the data back to the chip.Perhaps someone with a bit more knowledge of modern programming can point me in the right direction. I am attaching the old files used to do this.

author: martinator
author_rank: Contributor
timestamp: December 10, 2017, 05:29:10 pm
content: You can use something like the FM16W08 to replace your sram. You need to buy a soic28 to dip adapter to make programming easier,rearrange the address and data pins to match whichever application you have in mind and make a little circuit that pulses the chip enable after every address has been set up. Then you can read and write it like an eprom with a normal eprom programmer. I have also read out battery backed srams as eproms. You need to make adapters of course.You shouldn't need to build any special equipment, just buy a half decent eprom programmer.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 10, 2017, 06:10:33 pm
content: Quote from: martinator on December 10, 2017, 05:29:10 pmFrom what I read is replacing the chip on the original board with a FM16W08?That does not solve the problem. We still have to have a ram dump from the original chip. It cannot be removed from the board due to the memory is held there by the battery back up. So still have to build the interface to read this memory.If this is what you are saying. Remember, I am no programmer.

author: German_EE
author_rank: Super Contributor
timestamp: December 10, 2017, 06:30:46 pm
content: From what I have found there are two different versions of this board. The old version uses a 1K x 8 SRAM together with a HD7432 IC but the new version uses a 2K x 8 SRAM and not much else. Are schematics of these RAM boards available because I have no idea what the HD7432 is doing?As for reading the chip, apply 5V and ground to the right pins and monitor the four data lines. A binary counter or a set of eleven switches can be used to step through all 1024 addresses as you write them down. Before you start though you REALLY need to establish the function of pin 8 J17, is (WR) a write pin or write protect?

author: AF6LJ
author_rank: Unknown
timestamp: December 10, 2017, 08:05:13 pm
content: Over on the Icom 745 Yahoo group someone published a memory dump of the contents of the ram chip. For those who don't know radios like the IC-745, 751, IC-R70 and a few others contain set up information in volital ram that is battery backed-up...A couple of decades ago the folks over at PIEXX built and still market a replacement memory board that works in all these radios. One board that contains the microcode for all the Icom radios that used this module.https://www.piexx.com/?main_page=product_info&products_id=26It should be possible to build an adapter that will allow the contents of the ram board to be dumped into one of those old school E-Prom programmers.I have a couple of those RAM boards around here and it has been my experience the battery lasts for better than fifteen years.

author: albert22
author_rank: Regular Contributor
timestamp: December 10, 2017, 08:21:58 pm
content: Here:https://www.qrz.ru/schemes/contribute/technology/icom751/english.shtmlyou will find a diagram of the board, the programmer, and the binaries.There are a couple of replacement boards that include a RAM and an EPROM. One made by PIEEX and another by IK2RND.I didnt find any info on the memory map to differentiate what goes into the ram and what goes into the eprom.Does anyone have the schematics for ram+eprom boards or info on how to manage the CS and address signals ?Edit: while I was typing some posted similar data.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 10, 2017, 08:32:02 pm
content: Quote from: German_EE on December 10, 2017, 06:30:46 pmYes they were the a board and b board. I have several of these boards here in the shop that still work.I never had problems doing this with DOS base computers in the 80's. When you get old the mind does not see things in this modern day in age.Quote from: AF6LJ on December 10, 2017, 08:05:13 pmI found a few dumps on the web over the past few moths for the 745 and 751. I still have my original dump I made years ago.I am looking at the information albert22 posted below now. This really should not be that hard to do. But I could be wrong.Sue you have taught me a lot about the old 745 over the years.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 10, 2017, 08:37:47 pm
content: Quote from: albert22 on December 10, 2017, 08:21:58 pmYou are correct. I just installed one of each board in two different IC-745. Both boards work great. They both have a small problem and that is the foot print is not perfect on either. Also the IK2RND board does not allow you to bolt it back to the main board. Minor issues yes.I do remember seeing the information you posted a while back. The programmer they used is also parallel port driven. I do not think out of the 8 pc's I have running now any of them use a parallel port. My new ones do not even have a serial. All usb.I am going to look over some of the usb programmers on the market and see if there is a way to interface one to the ram unit.

author: AF6LJ
author_rank: Unknown
timestamp: December 11, 2017, 04:29:06 am
content: Quote from: Radio Tech on December 10, 2017, 08:32:02 pmI like my 745...I am thinking you might be better off buying a parallel printer port card and using your old DOS program ether on a Linux box or a box running FreeDos.Programming could also be done using the same adapter.....It wouldn't surprise me to find someone has already built and written up the software to program PROMS using the Linux operating system.Oh on the AM mod...I have hesitated doing that mod, I have felt there is an easier way to do the mod and get good high quality audio out of the radio.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 11, 2017, 09:54:59 am
content: Quote from: AF6LJ on December 11, 2017, 04:29:06 amYes they are decent radios and good receivers.Now that sparked an interest. I had already thought about getting a card and plugging it in. but then I remember from way back that dos programs do not run that good (or at all) on today's computers. I have not thought about Linux and emulation. This could work. May run by Best Buy this afternoon and pick one up. I do have a pc that is about mid 2000 that runs Linux. I am sure someone has already written it yes. I think you may just have hit the nail on the head Sue.QuoteI agree, just looks like a lot of work to switch it to transmit AM. Why would Icom do that? And they looked like it was done on a word processor from the 80's lol.I guess I will give it a go just to see.Thanks Sue.

author: AF6LJ
author_rank: Unknown
timestamp: December 11, 2017, 01:17:46 pm
content: it will be interesting to see how your progress goes.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 11, 2017, 03:20:51 pm
content: Quote from: AF6LJ on December 11, 2017, 01:17:46 pmI have forgotten all about Linux. I did a bit of reading this morning at 4am. From what I have read Using Dosbox in Linux will emulate dos running at 386 speeds. I cannot find my old programmer so just going to build a new one. Only need a CD4040 chip so will order a few of them today. This has me a bit excited.I know the point of doing this is really mute, since you can buy to modern day replacements. But how are we to know how long these folks will keep producing them? Plus old school is cool. And just like to be able to program them for the fun of it.

author: AF6LJ
author_rank: Unknown
timestamp: December 11, 2017, 03:41:15 pm
content: Quote from: Radio Tech on December 11, 2017, 03:20:51 pmGood deal, sounds like you are well on the way.

author: Co6aka
author_rank: Unknown
timestamp: December 11, 2017, 09:19:06 pm
content: Quote from: Radio Tech on December 11, 2017, 03:20:51 pmYou can configure the processor emulation and speed in the Dosbox config file, BUT the plain-vanilla Dosbox does not support the parallel port (unless something has recently changed) due to (infantile, IMHO) philosophical issues the developers have with old DOS games not needing parallel ports therefore Dosbox not having a need to support them. There are forks that do though, so you'll have to look for one that does.And AFAIK the Winderz version should also work fine; you don't have to run Linux. (Disclaimer: I run Linux, not Winderz, so me-no-test-myself.)Me-also-no-test, but you might be better off with QEMU plus FreeDOS on a machine with a parallel port.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 11, 2017, 11:06:21 pm
content: Quote from: Co6aka on December 11, 2017, 09:19:06 pmOh well, we will have to try something else then.Finding old computers that still work can be a chore. Not giving up yet. Going to ask some of my old Linux friends if they have anything.Thanks for your time.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 12, 2017, 03:23:46 pm
content: Sue,You ever heard of this?I find it interesting but I do not see how this works.See below...Quote

author: AF6LJ
author_rank: Unknown
timestamp: December 12, 2017, 05:10:22 pm
content: Quote from: Radio Tech on December 12, 2017, 03:23:46 pmI haven't heard that before, but it is worth a try.The author is banking on the CPU board writing all the band and mode data back to the RAM board.Here is what we know...1. Memory data is stored when memories are loaded with data.2. The last band and mode we were on is stored on the RAM board.3. The last modes and frequencies stored seen by the radio are also stored. .I think it is worth a try...Sadly the Icom IC-745 service manual doesn't have a detailed power up / power down description in the circuit theory section.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 12, 2017, 10:07:06 pm
content: Quote from: AF6LJ on December 12, 2017, 05:10:22 pmFirst I ever heard of this before. And like you said he is seeing this from the way a computer works.And from what we know from your 3 steps above he may be onto something.I am curious that there is no boot strap or boot loader involved in this. May be over thinking it a bit.Well the good thing is I have 3 of the original ram boards here that work. I an sacrifice one in the name of testing. But before I do I want to break out the logic analyzer and look at the data being sent on turn on, vfo movement, mode change, and band change. My logic device has 8 channels. Been wanting a good excuse to use it in some debugging. This should solve our missing details from the SM as you mentioned.Also if what he is saying then you could possible use a working ram board as a stand alone unit to program a dead one.This may get interesting.Schematic below.

author: AF6LJ
author_rank: Unknown
timestamp: December 13, 2017, 03:23:46 am
content: Quote from: Radio Tech on December 12, 2017, 10:07:06 pmThere is no need for a boot strap program, but there is the need to save some information regarding IF frequencies and such to make the display agree with where you are operating.With that said and having spent time thinking about this, there is a large chance this won't work, but it is worth a try.There is a slim chance the logic board writes data back to the ram module such as the first IF frequency (in Hex) If it reads it and for some unknown reason writes it back to the Ram Module you might be in luck, otherwise you will be building a programmer to load those modules after they have had the batteries replaced.QuoteThe service manual explains how data is loaded into the PLL board. The Matrix board is the glue logic that allows the Logic Board to talk to the front panel, along with a few other housekeeping bits of logic.

author: AF6LJ
author_rank: Unknown
timestamp: December 13, 2017, 03:26:45 am
content: One Other Thing...The PIEXX module has jumpers for the various Icom radios that use this Ram Module, This implies the same module is used for all the radios and the jumpers on the PIEXX module are used to change the address range depending on which Icom you are using, ...They load all the data for all the radios in the PIEXX module.

author: Co6aka
author_rank: Unknown
timestamp: December 13, 2017, 04:13:41 am
content: (O-Scope) Probe the "WP" pin of the RAM board while powering on and off and see what it's doing. The lower addresses of the RAM are normally write protected, which if I recall correctly is the purpose for the 7432. If "WP" is high then you can write to the lower addresses, and if it's low then you can't; normally it should be low. The interface ties "WP" high so the lower bytes can be written by the computer.Also, the software SHOULD run on fast CPUs since it reads the hardware timer. The issue is whether or not the OS allows low-level hardware access to I/O ports. If you've got a classic LPT port that supports bidirectional transfers, and can boot DOS, give it a shot. To test without the RAM board, tie the DATA lines in a certain pattern, hex "A" perhaps, and see if you read all "A" and so on. If so, then you should be good to go with the RAM board.

author: TheSteve
author_rank: Unknown
timestamp: December 13, 2017, 09:03:34 am
content: This is a very interesting thread. I have an Icom 271H and a 471H - both use the battery backed ram module and have the original factory batteries installed still. A simple replacement that doesn't require the battery would be great.

author: CJay
author_rank: Super Contributor
timestamp: December 13, 2017, 09:30:45 am
content: I think, with a working RAM board and an empty one, it would be possible to make a piggyback adapter that allowed you to copy the contents of the good one to the bad one, no PC necessary.Interested to know if there's a schematic of the board or at least a parts list (mainly just to know what the transistor is, I suspect a jellybean NPN type but...)Would be a fun project to use something like a PIC or Arduino to replace the entire board, I think it would be easy enough to find a chip with enough NV storage that it could be a one chip solution.

author: AF6LJ
author_rank: Unknown
timestamp: December 13, 2017, 01:10:58 pm
content: Quote from: CJay on December 13, 2017, 09:30:45 amThe idea of replacing the logic board with a modern microcontroller has crossed my mindYou could also replace the matrix board, which not only is in a bad place on the radio but overly complicates the process of reading switches off the front panel.Remote control could be added.I do like the idea of cloning a known good Ram board...

author: CJay
author_rank: Super Contributor
timestamp: December 13, 2017, 01:25:22 pm
content: Quote from: AF6LJ on December 13, 2017, 01:10:58 pmCloning looks like it might be very simple, just jumper the data and address lines between boards, assert WR on the board to be written to and count through the address space with a simple binary counter?Will attempt to reverse the board to a schematic and have a think later. Might be a little tricky as i've not got a board or indeed any of the radios the board comes from but it looks fairly simple, I assume the chip under the battery on the board with the larger SRAM is still a 7432?

author: AF6LJ
author_rank: Unknown
timestamp: December 13, 2017, 01:35:08 pm
content: For those who may want to play along at home...Here is the service manual for the radio.I would point out there are a number of undocumented items such as the first mixer diplexer that adjustment should not be attempted by those who are not sure what is going on. For whatever reason mention of this, and some tuning coils over on the PLL board were left out.As I remember one of the undocumented adjustments involves setting the injection level of the PLL sub loop into the PLL mixer. Too much sub loop injection and you get spurs, too little and the loop becomes noisy.When I bought my IC-745 I took it into work and ran a battery of tests on it.which included spectral purity. After spending a little time with the PLL schematic I took the radio back in a month later and cleaned up the PLL a little.These radios are getting long in the tooth, I bought my IC-745 as they were being discontinued in 1986.Thankfully I have a parts mule.

author: AF6LJ
author_rank: Unknown
timestamp: December 13, 2017, 01:36:12 pm
content: Quote from: CJay on December 13, 2017, 01:25:22 pmIndeed, looks to be that simple.

author: Ian.M
author_rank: Super Contributor
timestamp: December 13, 2017, 02:30:13 pm
content: The problem is 18 year old software with no sourcecode that bit-bangs the printer port to drive a 26 year old hardware interface design.However, if you don't need to access the hardware interface it works OK under Windows NTVDM, and can be used to load, save and edit its .BIN files, which is sufficient to figure out the file format. A very quick look indicates the file may be a simple sequence of 16 bit values, stored in low byte first order, of which the upper three nibbles of each are zero and the low nibble is the contents of that memory module location.The easy way forward would be to use an Arduino for the memory module interface, and create and publish a sketch that can read and write ICOM memory modules, and transfer data to/from a PC, preferably in a human readable format e.g. ASCII hex dump or IntelHEX, so it can be driven from any terminal program and isn't tied to an OS or even to a particular interface between the PC and the Arduino or similar board. An Arduino UNO should easily be capable of powering the memory module and controlling all its pins with no added hardware other than jumper wires. The sketch should document the interconnections, and also use pin names rather than absolute numbers so it can easily be ported to future generations of the Arduino platform. I believe an Arduino-based interface, with open source firmware will be highly future-proof, as Arduino-like boards are likely to be the de-facto standard for many years to come.Ideally someone with a fully working rig, + a spare memory module that has already lost its contents would volunteer to do the development, as that would be minimum risk as they could test with the blank module and the BIN images to be found on the web, and confirm normal operation before risking their good module. Otherwise, with a good reverse engineered schematic, + a N.O.S. RAM chip, it should be possible to build a functional clone of the memory board with a little effort.You'll also need to write a utility to convert the existing .BIN module dump files to your chosen human readable file format.The uPD444C 1024 x4 bit SRAM datasheet can be found athttp://www.pisi.com.pl/piotr433/manuals/upd444.pdfThe rest of the info needed can be found in this thread, though it would be nice to actually ID that transistor, and get the value of the vertical resistor next to it, or to have a schematic of the RAM board to work from.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 13, 2017, 02:39:38 pm
content: All, great informationIan.MI am not the sharpest tool in the shed when it comes to this type of stuff. But I do have working radios and spare EX-314 boards. All are the 2 chip solution. I will gladly sacrifice one. Will just need help on getting the correct data ect.I will get some decent pics of the ram board and also try and provide a schematic of it.

author: AF6LJ
author_rank: Unknown
timestamp: December 13, 2017, 03:07:28 pm
content: Quote from: Ian.M on December 13, 2017, 02:30:13 pmGood call...A stand alone programmer could be cobbled together with a minimum of effort.

author: CJay
author_rank: Super Contributor
timestamp: December 13, 2017, 03:10:07 pm
content: The vertical 'resistor' is a diode, it's probably something like a 1N4148 or equivalent, the transistor, as I mentioned earlier, I think it'll just be a jellybean NPN part.The PCB diagram in the archive that has the 2Kx8 D446 SRAM in will be pretty much the same circuit, they're ignoring the upper 1024 byte chunk of the larger SRAM and they've also ignored the upper four bits of the data bus.Probably worked out cheaper to fit the larger chip than source more of the older 4 bit devices.If nobody beats me to it I'll draw up the schematic when I get home.It will be pretty trivial to build up an adapter to plug one of those boards into an EPROM programmer, an adapter to write one in the same EPROM programmer would probably also be pretty simple.Definitely wouldn't bother making a clone of the board as it stands, some form of NVRAM which retains contents even without power would be a far better idea, a 24C01 and a CPU would be a far better solution but I'm not sure about Arduino, can you manipulate the clock speed on them and disable the on board oscillator, I ask because the clock is smack bang in the middle of the HF spectrum and could cause all sorts of problems...

author: Ian.M
author_rank: Super Contributor
timestamp: December 13, 2017, 03:46:38 pm
content: No, an Arduino or other MCU would *NOT* be a good choice for a replacement for the memory board. Responding to an address pin change fast enough is likely to be difficult and adding an extra source of digital noise to a sensitive radio receiver is seldom a good idea.While it may be worth considering a FRAM based replacement board, unless you need the extra memories that are provided by the commercial board that has been discussed earlier, surely the easy option is simply to fit a battery holder (which will be a bit of a bodge job - Epoxy putty or 3M VHB tape + patch wire), which will get another 10 years out of these rigs before you have to revisit the problem. Either way, you'll need some sort of programmer

author: CJay
author_rank: Super Contributor
timestamp: December 13, 2017, 04:23:14 pm
content: Quote from: Ian.M on December 13, 2017, 03:46:38 pmI don;t think the access speed is likely to be a massive problem, I am concerned that adding an extra clock signal into the mix, literally perhaps, might cause problems with the receiver but I think it's highly possible that an MCU could be run at the same clock speed as the main CPU, working on the assumption that Icom don't have issues with that 4MHz leaking into the receiver.I don't have a radio to check out for myself but I can say that I've built PIC circuits before now for use in radios and experienced no problems with the clock affecting the receivers, YMMV of course and the IC-745 is a completely different beast to the ones I've played with, I think it's worth the experiment.Adding a battery holder would still leave you open to losing the SRAM contents if you develop a bad contact or the battery goes flat so some sort of flash or non powered NVRAM is preferable.

author: AF6LJ
author_rank: Unknown
timestamp: December 13, 2017, 04:51:50 pm
content: Replacing the Ram board with any kind of microcontroller is a bad idea.If you are going to do that, replace the whole logic board, the Ram board and the radio's Matrix board. The signals on those boards are relatively low speed, in order to keep down the noise generated by all that digital logic.Anything that runs too fast will be a PITA to suppress all the EMI...

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 13, 2017, 04:52:28 pm
content: This is starting to get exciting.Lets remember a few things as we move along.1-At this present time we can order replacement boards with non volatile memory. In fact I am going to order the IK2RND board for my own use. I will not reverse engineer it as I do not want to take someone else work. Plus this is an option for those that do not want to experiment in the name of learning. At this time however how long will they continue to produce these boards?2-Building a replacement board ourselves would be fun and exciting. Should be a great learning experience for folks. Will help us understand what was going through the minds of the designers during this time frame. My biggest thought was bean counters. As Eeprom design cost way more back in that era.3-For nostalgia, learn how to use modern equipment to read and write to the existing EX-314 ram board. For those like myself that would like to keep all the original parts intact and working. We already have the programmer and software designed to do this, what we do not have is the current delivery system.I did dig out a win 3.1 and a win 98 pc from the back of the shop yesterday. And they workI could simply find my old programmer or build a new one. But how long these machines will run is beyond me.Keep the thoughts and ideas flowing guys.

author: CJay
author_rank: Super Contributor
timestamp: December 13, 2017, 05:03:07 pm
content: So could you make some measurements, if you could capture a read and a write sequence so we can get some kind of idea how fast they are?Also would be interesting to see a capture of the control signals in relation to the data and address lines.Plus, the number off that transistor?It does occur to me that it may be possible to just fit or wire something like an Atmel AT28C16E in place of the SRAM chip but they're long imn the tooth and I don't know if they're still available...

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 13, 2017, 05:08:13 pm
content: Quote from: CJay on December 13, 2017, 05:03:07 pmThis will be my priority for the next few days. I been wanting a reason to learn how to use this logic analyzer. I will get some high res pictures and part numbers from the board this afternoon. Will document and most likely record this journey. Will post everything I find here.

author: Silveruser
author_rank: Regular Contributor
timestamp: December 13, 2017, 09:06:49 pm
content: I've been following along, Just replaced the battery in my R71A after all these years - I've no idea how many, maybe ten , maybe 20. I finally found the service manual after months of looking and found photo copies of these documents tucked inside. The first (attached) is a blurb from ICOM about how great this idea is. The second is a bunch of RAM dump printouts. I've no idea where they came from or if they are of any use but here they are from the days of dot matrix. If you think they would be of any value let me know - I'll see if I can find a way to share them.

author: CJay
author_rank: Super Contributor
timestamp: December 13, 2017, 09:10:49 pm
content: The interesting thing in there is the bit that says the programming information is available from Icom and that users with a PC can experiment.Which to me would suggest there's a way to load these in the radio...Would be very interested to see more documentation.

author: TheSteve
author_rank: Unknown
timestamp: December 13, 2017, 09:41:06 pm
content: Quote from: CJay on December 13, 2017, 09:10:49 pmThey mention needing a home computer so I would think at some point Icom considered selling a programming interface.

author: Silveruser
author_rank: Regular Contributor
timestamp: December 13, 2017, 09:55:53 pm
content: They did make an Interface Unit EX309 for the radios. i have one installed in mine. Never used it. Don't recall ever seeing any instructions on commands/control possible. It just came with a single page with some pinout info and installation instructions.It might be interesting if someone could find more of those Tech Talk notes. So far nothing much on ICOM sites, some more recent ones but nothing old. Maybe time to check the WAYBACK Machine.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 13, 2017, 10:12:51 pm
content: Silveruser,that is great information. at this point we can use anything that is available for further testing. Thanks for sharing that.I also agree that Icom may had that in mind after reading that article. If they ever let this information out is beyond me. I have contacted Icom in the past for information on old radios and all I got then was "Sorry, we no longer support that". So unless we find a tech from the 80's that used to work for them I am pretty sure this information is mute. Hence why I started this thread here and started some videos on the 745. I think I will also start hunting for "parts and donor" rigs to help with some of the experiments. I do own a rig in good working order that appears to have the original battery in it. From that article the battery is only needed when the unit is not being used.I just got home from work, went out to the shop and it is a chilling 38 degrees in there. Will take an hour or so the heat up then I will spend a bit of time tonight looking things over. Really need to get the house lab back together now.I do have a EX-314 board in hand. That transistor (Q1) is a C945. Like you said cJay just a jellybean part.D1,D2,and D3 looks to be 1N914.C1 the big green ceramic is a 104M (0.1)C2 is a 47 (47pf)R1 47kR2 390R3 10kR4 4.7kR5 1.0kR6 47kW1 - W8 1 ohmW9 jumperIC1 HD7432PIC2 D444CTR1 C945

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 13, 2017, 10:24:17 pm
content: Quote from: Silveruser on December 13, 2017, 09:55:53 pmVery interesting and thanks again. I did a quick search and found the below. I did not find it on ebay however, all have been sold.

author: CJay
author_rank: Super Contributor
timestamp: December 13, 2017, 10:25:06 pm
content: Well that EX-309 seems to be an interface to the CT-10 which is capable of being interfaced to an RS-232 capable computer or terminal.It's a bit of a mire of equipment.I think tracing the EX-309 connections in the IC-751 logic board schematic, J10 and J15, might be interesting but we're diverging from the original subject now, I don't think it's of much use unless we get the CT-10 and whatever software Icom made available for that combo.It's late here, I'm up again at 05:00 and it's almost 22:30 now so more digging tomorrow.I reckon the parts list for the larger chip board will be exactly the same except for the D444 being swapped for a D446?Quote from: Radio Tech on December 13, 2017, 10:12:51 pm

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 13, 2017, 10:49:46 pm
content: Quote from: CJay on December 13, 2017, 10:25:06 pmYou may be right, was just thinking there could be some tid bits in the docs that could be useful.I have attached the version A and B so the difference can be shown. I have the A version here somewhere.Get some rest....

author: Co6aka
author_rank: Unknown
timestamp: December 14, 2017, 12:20:16 am
content: In the ZIP file for the "RAM Module Programming Utility" on "www.n2cbu.net" there are a couple of RAM dumps in both BIN and HEX; compare the two and you'll have the BIN format, which is pretty obvious.PCB layout for the RAM board is in the ZIP, and attached here for simplicity.EX-309 is just a parallel remote control interface along the lines of the serial CI-V interface.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 15, 2017, 01:02:26 am
content: Thanks for that information. I have looked at the dumps of those but I am not a coder. Will take me a while to figure all that out.Any way back to what I was talking about on the radio programming a dead board by swapping it out while the unit is powered on.... Big fail. Will not work. As soon as the ram board is removed the display goes all "0". So there is something being sent to the cpu when the ram is there. I was 99.9 percent this would be the cause. Even Sue had her thoughts on it. I recorded the experiment and will upload it shortly for your entertainment.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 15, 2017, 01:50:39 am
content: The Failure

author: Co6aka
author_rank: Unknown
timestamp: December 15, 2017, 03:33:00 am
content: Quote from: Radio Tech on December 15, 2017, 01:02:26 amThe RAM board also contains/holds the current frequency, along with "VFO-B" and memories. I wonder if a supercap across the RAM chip's supply lines would hold it long enough the change the battery.Anyway...best bet is to set up a PC with a good-old-fashioned parallel port and give it a go with the interface. I haven't programmed one of these boards since at least ten years, but it had to have been while running a P4 CPU. Key is the parallel port, not the CPU, so it should work with a PCI or PCI-X parallel port card, and those are pretty cheap. First grab a FreeDOS image, burn it, and see if you can boot your PC with it.

author: Co6aka
author_rank: Unknown
timestamp: December 15, 2017, 03:55:46 am
content: I while back a couple of Russians had done some RAM board hacking... So I poked around on Yandex and found this:http://yl2rmk.qrz.ru/icom751a.htmlhttp://www.qrz.ru/schemes/contribute/technology/icom751/english.shtml

author: AF6LJ
author_rank: Unknown
timestamp: December 15, 2017, 01:01:30 pm
content: There is minimal information in the service manual regarding how the memory module is mapped. the Russian information is much more valuable.A word on the lower frequency limit for the receiver....The PIEXX module takes the radio down to 10KHZ, while you won't hear VLF signals down there the radio is quite useful below 60KHZ, which means you can hear WWVB on a quiet night on an active loop or a longwire antenna. The PLL will be noisy down toward 30KHZ injection level from the sub loop into the main loop mixer has an effect on this noise, it also has an effect on spurs generated by the PLL. Don't be surprised at the level of noise as you approach 0HZ...

author: AF6LJ
author_rank: Unknown
timestamp: December 15, 2017, 01:02:39 pm
content: Looking forward to watching the video Buddy, will do sometime later on today.

author: CJay
author_rank: Super Contributor
timestamp: December 15, 2017, 01:05:52 pm
content: See, now I really want one of these radios so I can get hands on and experiment but they're *rare*, all I can find is ones broken down for parts.I'm not actually that interested in using it though, I've already got myself an Icom HF set...

author: AF6LJ
author_rank: Unknown
timestamp: December 15, 2017, 01:17:51 pm
content: Quote from: CJay on December 15, 2017, 01:05:52 pmThe IC-745 has a really good receiver, and if care is taken in aligning the PLL, the undocumented adjustments it can be a very quiet receiver.They are getting old enough that recapping is not a bad idea, but that will be a lot of work.Other radios based on much the same hardware would be the...IC-751A and the IC-765.

author: AF6LJ
author_rank: Unknown
timestamp: December 15, 2017, 01:24:20 pm
content: Quote from: Silveruser on December 13, 2017, 09:55:53 pmThe Interface unit was used among other things transcieve operation with an Icom R-70.Years ago I installed one for someone I knew for that purpose.

author: Co6aka
author_rank: Unknown
timestamp: December 15, 2017, 05:58:43 pm
content: Quote from: AF6LJ on December 15, 2017, 01:01:30 pmAlso, instructions for editing the lower and upper frequency limits are in the text file in the ICOMRAM.zip file, and it might be more practical to change the lower limit to 9kHz instead of 10kHz. As for the sensitivity rolloff below 100kHz, that can be rectified by overhauling the front end bandpass filter. I did several of those back in the days but I've lost all of my mod notes. If there's a way to add another 48 hours to my days I'll do a teardown on my R71A and reverse-engineer my mods. (My battery is long dead so I too need to dig out my interface and reprogram it.)I do recall that one of the issues is with an inductor that creates the ground return for the DC that operates the PIN diodes... Initially I went up a couple orders of magnitude, but my final mod involved switching the sub-HF bands (500kHz to 1.6MHz, and 100kHz to 500kHz, if merembercorrecry -- now I actually am a "OM") with tiny RF relays. I had also modded the PIN driver circuitry to drive the diodes harder. There's also a moronic attenuator in the sub-HF front end filters, at least in the R71 receiver, that's begging to be removed. Anyway...my R71A ended up being quite hot all the way down to 10Khz, and merember listening to something that's on 10kHz. Oscillator noise is an issue and that'll become quite apparent as you approach 10kHz, but again that can be significantly reduced.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 15, 2017, 07:20:05 pm
content: Quote from: AF6LJ on December 15, 2017, 01:02:39 pmCool deal Sue. Nothing fancy no technical stuff in it. Just mostly trying this swap and some flapping.I really appreciate all this information you guys are sharing.I had to work all day today, had 8 hours in at noon. Was going to run to town and pick up a parallel port from Best Buy but I just spent some time searching for my old programmer. Can not find it, may be in the attic. Started looking for ,y box of old chips, need another CD4040. Can not find those lol. My store room is stacked to the ceiling with boxes.Ordered a Arduino ultimate starter kit today. Going to try and talk with it using that. We will see.

author: Ian.M
author_rank: Super Contributor
timestamp: December 15, 2017, 07:54:31 pm
content: To give you a head start on accessing parallel memory with an Arduno, take a look athttp://danceswithferrets.org/geekblog/?p=315which reads a 27128 EPROM using an Arduino Mega. As the ICOM memory module has half the number of data lines, and fewer address lines, you should be able to use the Arduino Uno you are getting in your starter kit.Take the sketch code from that link, delete the lines that refer to higher numbered address pins or data pins the module doesn't have, re-allocate the pins to pin numbers that the Uno has free(don't use 0 or 1 as they are needed for the comms link to the PC, but you can use the analog pins, seehttps://www.arduino.cc/en/Tutorial/AnalogInputPins), delete the line in the loop() function that prints the upper nibble of each byte:Code:Serial.print(hex[ (d & 0xF0) >> 4 ]);and delete the ASCII dump code that follows it a few lines later, keeping the line:Code:Serial.println("");onwards, and you should be reading ICOM memory modules with under an hour's work.When you start adding code to write to the memory module put 330R resistors in series with each data line so if you FUBAR the timing to change the data pins from inputs to outputs, and do so while the module is still in read mode, any level conflicts don't cause damage.

author: AF6LJ
author_rank: Unknown
timestamp: December 15, 2017, 08:17:30 pm
content: Quote from: Co6aka on December 15, 2017, 05:58:43 pmThe R-71 has a better PLL than the IC-745, as I remember the loop is a three order PLL as apposed to the two order PLL in the 745, both will do 10HZ steps. The 745's RX front end does lend itself to mods for LF / VLF, I have wanted to do it for many reasons, not the least of which is for listening to nature using a microphone instead of an antenna (10-50KHZ).

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 15, 2017, 08:32:48 pm
content: Quote from: Ian.M on December 15, 2017, 07:54:31 pmThanks.I am new to Arduino. Zero experience so that too will be a learning curve. Appreciate the heads up.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 15, 2017, 08:35:09 pm
content: This was just emailed to me by a user named Phil.May help a bit.

author: AF6LJ
author_rank: Unknown
timestamp: December 15, 2017, 08:51:01 pm
content: Thanks buddy that looks right to me.I reversed the A module sometime back and never documented it much more than a back of the envelop drawing, and that agrees with what I had.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 15, 2017, 09:04:53 pm
content: No problem Sue. Phil tells me he has more information he may share also.This is going to turn out to be a great project. He found this on a Japanese forum some time back.Glad to know I am not the only one that draws stuff on envelopes. I do this all the time. Also sales flyers, scrap paper. boxes ect. Where I used to work I even drawn schematic right on the bench! Problem is you can never find that little piece of paper a few weeks later.

author: Ian.M
author_rank: Super Contributor
timestamp: December 15, 2017, 09:24:30 pm
content: Phil's RAM module schematic + the uPD444C SRAM datasheet I linked to in reply #27, clarify the remaining issues that needed resolving to desigh an Arduino based programming jig. Q1 is configured as an inverter, with a speedup cap and a Baker clamp, and when combined with the quad OR gate, only allows /WR through to the RAM /WE pin, if one or more of AD8, AD9 or WP is high. WP is low impedance. AD10 is the RAM /CS signal. The programming jig should tie WP high to allow the whole memory to be written.To read it simply keep /CS low, and /WR high. Apply a 10 bit address on AD0-AD9 and read the data on D0-D3.To write a location, start with /CS and /WR high, and the desired address on AD0-AD9, Take /CS low, then /WR low. Set D0-D3 as outputs with the desired nibble to write on them, then*take /CS high and set D0-D3 back to inputs then finally take /WR high. This sequence avoids data bus conflicts between the Arduino and the memory module.The Uno has *just* enough pins to interface to the memory module.* theoretically there is a 300ns delay here but an Arduino clocked at 16MHz has an instruction cycle type of 62.5ns, so it needs less than five cycles delay, and digitalWrite() is notoriously slow on AVR based Arduinos so no extra delay will be needed.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 15, 2017, 09:57:55 pm
content: Wow Ian.MIt really amazes me how you guys can look at the schematic and see how that code flows. Truly an art. With what little bit I done over the years, (mostly in the 80's) I will not even pretend to understand all that you posted. A lot od studying for me. It is great to hear the Arduino has just enough pins and slow enough to get the job done. Looks like we just may learn a lot from this and not only set the goal for reprogramming the original data back to the board but make it a lot better than it was.This has me so excited.Arrr 502 bad gateway from forum. Lost all the information IO spent 30 minutes trying to say.

author: Co6aka
author_rank: Unknown
timestamp: December 15, 2017, 10:41:50 pm
content: Quote from: Ian.M on December 15, 2017, 09:24:30 pmActually, it would be better to have WP normally-low so "just in case" the critical low-address data is protected while reading and verifying an incoming board. Perhaps use a switch and add red/green LEDs to indicate the protection state. I kinda like the Arduino idea; provide default config data for all models, and offer the option of altering high/low freqs, etc. Makes me recall the days of the R-1801 -- damn I'm OLD.FWIW, the replace-the-CPU-board idea is something I've always wanted to do. The functions of the CPU in these radios are trivial, and with a modern controller it'd actually be a fun project. Add USB, maybe ethernet and bluetooth, at least 100,000,000 memories, robo-scanning, the voice of HAL-9000 with some custom tweaks for Dave.

author: Ian.M
author_rank: Super Contributor
timestamp: December 15, 2017, 10:59:50 pm
content: Have the switch disconnect /WR and take it high to protect the whole memory.Handling all the fancy stuff like default data, editing memories and frequency limits etc. can be done PC side The Arduino then only has to handle the memory board interface, reading and writing individual nibbles or blocks of nibbles on command, with a command to set all interface pins to inputs so that power to the memory board can be removed to allow it to be connected/disconnected without powering down the Arduino.

author: German_EE
author_rank: Super Contributor
timestamp: December 16, 2017, 08:38:24 am
content: I agree with the circuit analysis y Ian M and at last we know what that CMOS chip does. I don't think it matter too much but make sure that you pay attention to the address pins on the RAM as there is NOT a one to one mapping of the pins. In theory you can use address pins in any order and the ICOM engineers probably did it this way because of PCB layout.Trying to get to sleep last night I was thinking about this problem and it might be possible to replace the entire contents of the PCB with a single chip. If a processor such as a PIC or Arduino could monitor address lines 0-10 plus a handful of control lines then we could use the data lines without modification, just wire them straight to the data bus on the transceiver. Most micros these days contain some NVRAM and this could be used for parameter storage.As mentioned before RFI is the only issue and I don't know how the receiver will react.

author: Ian.M
author_rank: Super Contributor
timestamp: December 16, 2017, 10:38:22 am
content: That's a lot harder than it would initially appear to be. The use of a speedup circuit for the NPN inverter indicates that the set's access to the memory board has fairly fast timings, at least during write cycles. Assuming back to back execution by the set's 4MHz CPU, of setting an address or strobing a control pin and expecting a result, a MCU emulating the memory module would have to respond within one instruction cyvle of the set's CPU, and even in hand-optimised assembler, with an order of magnitude faster MCU than the set's 4MHz processor, that would be difficult. The more you push up the clock speed to ease this constraint, the worse the EMI problems.IMHO developing a replacement for the set's CPU and doing away with the need for the battery backed memory board would be the optimum way forward. For EMI reasons, I wouldn't advocate bringing USB into the set, so a slew rate controlled opto-isolated serial interface would probably be the best option for those wanting PC control and management.

author: albert22
author_rank: Regular Contributor
timestamp: December 16, 2017, 01:20:08 pm
content: I had no time to read the last posts. Just gave a quick look at the schematic. BTW thanks a lot for it and other useful info that have been posted.The memory map of the module seems to be clear now. It defines what part of the memory is RW and which is Read only. Making it possible to separate the memory in two chips a RAM and an EPROM just as the commercial modules do.The other conclusion is that it is not possible to clone modules by swapping them when the rig is powered on.Again I just did a quick glance, later I will try to study it with more detail.I have not powered my 751A in years and a friend of mine has lost the data on his 751 so I will try to go with the RAM/EPROM solution.regards

author: AF6LJ
author_rank: Unknown
timestamp: December 16, 2017, 01:47:29 pm
content: A universal programmer using an Arduino is a worthy project, not just for this but for other projects radios as well.A logic board replacement is a nice idea, however the radio really doesn't lend itself to remote control operation, a very limited number of functions are not analogue.One advantage to building a replacement logic board would be to eliminate that annoying jump in carrier frequency when changing modes. The fact that Icom didn't deal with that to begin with indicated a bit of laziness on their part.These radios were set apart from others of the time for many reasons.The receiver preformed very well for its day. The noise blanker was one of the very best you could get at the time for the Soviet OTH Radar. Also the 745 represented the dividing line between the low cost radios Icom made and their higher tier radios. The only thing that separated this radio from the 751A, 761 was feature set 765, While the IC-781 was the top tier radio it was in a class by itself.The other three radios did share quite a bit in common with the IC-745.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 16, 2017, 04:53:04 pm
content: Thanks for all the information all.I agree Sue, the Arduino programmer may be the best yet. And as you said not just for this radio but for many others out there.This morning I was rambling in the shop trying to find the programmer I built years ago. Still no luck. It is here somewhere. If I could find it I would probably be in luck old school.I found my original computer Intel Celeron (386?) with Windows 98 on it. I also found my old Modular Circuit Technology 4 gang eprom programmer Mod-Met-4The machine powered up and the programmer still works. Pity the programmer will not work for this.The programmer has it's own card that plugs into the pc.On top of the PC is an ultra violet eraser.Last picture is a dump from a 27128 chip using an editor

author: German_EE
author_rank: Super Contributor
timestamp: December 16, 2017, 05:27:25 pm
content: I was once told that good engineers never throw anything away, it's always saved 'just in case it comes in useful someday'.Now we know why.

author: AF6LJ
author_rank: Unknown
timestamp: December 16, 2017, 05:59:15 pm
content: Quote from: Radio Tech on December 16, 2017, 04:53:04 pmYou could use that.....You would need to build an adapter, so it is possible.However.....I think all the PC overhead is overkill for projects like this in this day and age.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 16, 2017, 06:32:01 pm
content: German_EEI never throw anything out. One of my many problems LOL.Agree Sue,Patiently waiting for my Arduino to arrive. Should be here on the 21st. Just in time for Christmas break.Until then I have lots to do here. I am watching lots of Arduino videos to absorb some of that.I watched one guy how he used shift registers to add more programming pins. Very interesting.I really need to study up more on this stuff. It is just all 1's and 0's right? Just know how to place them.I do have a bit of newer programming stuff to play with. Perhaps it can help me learn more also.

author: AF6LJ
author_rank: Unknown
timestamp: December 16, 2017, 07:02:15 pm
content: Looks like you have plenty to keep you busy with Buddy

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 17, 2017, 11:56:12 am
content: Always SueSo last night I was looking at the idea of building an adaptor that would fit my current old school programmer.I was looking at how other types of chips are programmed with it.This got over my head quickly. And this is because I think that the ram unit acts like the complete chip.SO I think the adaptor would need is own circuitry to do this.

author: AF6LJ
author_rank: Unknown
timestamp: December 17, 2017, 01:40:01 pm
content: Quote from: Radio Tech on December 17, 2017, 11:56:12 amThat board is just like a PROM... sort of...You have data and address lines all 5V.You have a programming line and you have data lines along with 5V and ground.As long as you can set up the programmer to use 5V as the programming voltage you should be good.The other issue...The Chip Select line, is the last address line and as long as it is active when you are reading / writing to the board should not present a problem.That's my thinking anyway and as usual anybody who sees something I have neglected please chime in...

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 17, 2017, 04:49:47 pm
content: I had the feeling it was. This can get complicated for the young players for sure.Thanks for thatI was digging around this morning and found the old programmer. I think this was the second one I built.But missing the CD4040, But brings back a few memories.Ok, so to get back n topic when my Arduino arrives I need to build another board to hold the ram board. Perhaps on a bread board?

author: Ian.M
author_rank: Super Contributor
timestamp: December 17, 2017, 06:42:36 pm
content: Why? You just need to jumper from the Arduino female headers to the board's pin connectors. A jig to hold the memory board is only going to get mislaid between now and when you need it again in maybe ten years time.However a breadboard could be useful for adding 330R resistors in the data lines during development so mistakes in the AD10 (/CS), /WR and data direction sequencing don't do any damage. You only need it on the J2 (small connector) side of the board.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 17, 2017, 07:26:38 pm
content: That is true. But the resistors is a thought. Probably the breadboard would be the best idea.Remember, I am a noob when it comes to all this stuff and I really appreciate the information.

author: AF6LJ
author_rank: Unknown
timestamp: December 17, 2017, 10:43:18 pm
content: I am not sure the resistors are necessary, we are all talking 5V logic here.The only issue is don't connect / disconnect with power applied.

author: Ian.M
author_rank: Super Contributor
timestamp: December 18, 2017, 04:10:10 am
content: Maybe, maybe not. It would be a shame to blow the 'unobtanium' RAM chip due to a code error causing a bus conflict during development. Of course, once the code is tested, and the read and write functions finalised, they wont be needed any more so future users will only need a Arduino and aq pack of jumpers. Looking at the very wimpy drive capability of a uPD444, they'd probably better be 1K rather than 330R.

author: CJay
author_rank: Super Contributor
timestamp: December 18, 2017, 01:11:05 pm
content: Well the 'unobtanium' chip actually isn't at all, it's a 1kx4 SRAM and I'm pretty sure it's just an NEC version of the 2114 SRAM, they're very easy to get hold of, they were used in an awful lot of old computers and are all over eBay for a couple of £ each.Have a pile of parts arriving today so I should be able to mock up a RAM board and test my Arduino sketch to see if it works, I hope it's going to be able to copy from a 'master' RAM board and program a dead board.Once that works I will add a few facilities that should make life 'interesting'.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 18, 2017, 10:29:33 pm
content: Good stuff cJay. Looking forward to what you find..I ordered my Arduino Friday. It came today. Wow that was quick. Must had been an Amazon seller.Who wants to bet it will not all fit back in the case?Now I can sit down and start learning some of this.

author: AF6LJ
author_rank: Unknown
timestamp: December 18, 2017, 10:42:38 pm
content: Very Cool...

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 23, 2017, 02:04:57 am
content: Thanks Sue. Should be fun.Off for the next week and a half, Will have some time to play around with the Arduino a bit. Pretty sure I will not learn how to program a eprom let alone the ram unit with it anytime soon. Lots of learning.In the mean time I will be restoring a Hammarlund HQ-180 a viewer sent me. Not a bad receiver and looks pretty good.

author: AF6LJ
author_rank: Unknown
timestamp: December 23, 2017, 02:22:56 am
content: Looks good Buddy, have fun.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 26, 2017, 09:27:41 pm
content: Well the week end has been a failure. I build a new N2cbu programmer. Read reading the ram board I get all F's in the window. If I load the IC745fin.bin and try and write I get a verify error. Using a NEC4040 chip on the programmer. I verified the thing was built correctly.Tried on 2 old machines. A 386 running Windows 98 and a 286 running 3.1.I changed the port in bios several times and no go.

author: Towger
author_rank: Super Contributor
timestamp: December 26, 2017, 10:38:46 pm
content: Running a DOS program in windows is always going cause timing problems.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 26, 2017, 11:18:20 pm
content: Quote from: Towger on December 26, 2017, 10:38:46 pmSame results on the 3.1 machine. In full dos mode

author: AF6LJ
author_rank: Unknown
timestamp: December 26, 2017, 11:20:36 pm
content: Someone check me on this..The old DOS Mode command is used to set the speed of ports, I cannot remember if it works on the parallel port.

author: Ian.M
author_rank: Super Contributor
timestamp: December 27, 2017, 12:09:39 am
content: No. MODE doesn't do anything useful to the parallel port hardware.N2CPU's ICOM-RAM application will be bit-banging the parallel port registers and, as there isn't a maximum limit for any of the RAM access timings, Windows 3.1 or 9x won't interfere with it. Back in 2001, I was running a parallel port PIC and I2C EEPROM programmer based on David Tait's PP design, with my own DOS software written in Borland Turbo C (for MSDOS), and a quick look at the source code doesn't show anything special to add support for running under the Windows 98 SE I was using at that time, so I am *absolutely* certain there were no significant issues doing direct parallel port access from a DOS application under Windows before NT/2000/XP etc. However, you did have to make sure that none of the Windows printer drivers were attached to the port in question.The most likely cause of the above failure is the port hardware doesn't support the bidirectional mode N2CBU's software expects to use, or possibly the port address is incorrect or not valid for MSDOS mode.Without N2CBU's sourcecode, its fairly hopeless, which is why I proposed writing new software to use an Arduino.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 27, 2017, 02:42:42 pm
content: I am about to retire the idea of getting the N2CBU programmer running. I played with it all day yesterday.After emailing Phil he said the olny change he made was to go into bios and change the port from ECP to standard. In fact I tried all settings. In the program you can click on "port" and change it there also. Tried all combinations with it. In the mean time I have been watching and reading up on Arduino. No real tutorials out there on programming this type of eprom. A lot to take in so looks like this project is to take a little time till I can under stand how all this works. All this is new to me.Thanks for every ones input. It is much appreciated.

author: AF6LJ
author_rank: Unknown
timestamp: December 27, 2017, 02:46:54 pm
content: Quote from: Ian.M on December 27, 2017, 12:09:39 amI couldn't remember for sure, it had been twenty years or so since the last time I played with DOS.

author: Ian.M
author_rank: Super Contributor
timestamp: December 27, 2017, 03:18:04 pm
content: 16 years here, but at least I had the archived PP/PPE programmer project to refer to that had been copied across from one PC to the next till it reached my current one.

author: HighPrecision
author_rank: Unknown
timestamp: December 27, 2017, 05:28:38 pm
content: I've used a simple adaptor for device programmer set for DS1220 NVRAM, binary file must be loaded from 0x400 (offset) or simply duplicated.The four resistor are simply pull-down for unused data bits [7..4]

author: HighPrecision
author_rank: Unknown
timestamp: December 28, 2017, 04:41:23 pm
content: Quote from: HighPrecision on December 27, 2017, 05:28:38 pmThis adapter is not directly compatible with N2CBU binary files, it is neccessary to split files with 'binsplit' tool (http://www.s-record.com/), one part contain the full lookup-table of the ICOM radio, other part only 0x0 data to be discarded.Attached is a set of modified files (from N2CBU and RW3AX), ready to loaded in programmer without offset (start at 0).73's

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 28, 2017, 05:34:27 pm
content: Thanks for the work.I really not sure what I am doing but when I try loaded the IC745FIN_n2cbu-D.BIN into the programmer it returned an error.I was just going to look at the file to see differences. See below.Perhaps this is for the Arduino programmer?

author: HighPrecision
author_rank: Unknown
timestamp: December 28, 2017, 07:15:11 pm
content: Quote from: Radio Tech on December 28, 2017, 05:34:27 pmMy adapter is for standard device programmer (eproms, etc.), I have used the GALEP3 with no problems, probably a chinese TL866 is also ok, on the programmer software select a Dallas DS1220 NVRAM (Non Volatile RAM) chip to be programmed.N2CBU software is obviously non compatible with my modified files, but it works only on old DOS PC, the adapter showed in my previous message permit to recover ICOM RAM boards using actual PC (Windows) and a more or less recent standard device programmer.QuoteDepends on how it is programmed, Arduino is a platform that can be adapted to many applications, not just a programmer.73's

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 28, 2017, 08:12:34 pm
content: Quote from: HighPrecision on December 28, 2017, 07:15:11 pmCool, I may give it a try also. Banggood is sending me TL866 programmer for free when they get more in stock. This will replace my old DOS based programmer. That still works btw.QuoteInteresting, I am way behind in my dos programming skills. I do have a windows 3.1 machine here that seems to work fairly good.Not sure what the IC is on your board maybe I over looked it. Looks very simple to put together.

author: HighPrecision
author_rank: Unknown
timestamp: December 28, 2017, 08:37:34 pm
content: Quote from: Radio Tech on December 28, 2017, 08:12:34 pmThe DIP-24 in my PCB image is a plug soldered behind the board, to be inserted in programmer ZIF socket, in PCB front there are 2 strips (8 and 12 pins) for ICOM RAM board insertion.See the DS1220 datasheet to check electrical connections between ICOM RAM and the programmer socket.73's

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 28, 2017, 08:54:45 pm
content: Quote from: HighPrecision on December 28, 2017, 08:37:34 pmBrilliant!I do notice dip-24 on the board now.That is nice. Trying to do too many things here at one time lol.The 4 resistors 1k? I may try this with my old programmer.Thanks.

author: HighPrecision
author_rank: Unknown
timestamp: December 28, 2017, 09:51:01 pm
content: Quote from: Radio Tech on December 28, 2017, 08:54:45 pmThese resistor are not critical, I've used 2k2, but 1k is ok

author: AF6LJ
author_rank: Unknown
timestamp: December 28, 2017, 11:37:02 pm
content: It's good to see this project moving along.Can't say as much for my current project....Stalled for a day or two.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 29, 2017, 02:12:42 pm
content: Yes I agree Sue. So nice when folks can get together and figure out a problem.What project you working on?So Banggood notified me and said that it will be a month before they have the TL866 programmers back in stock. So I told them to hold off.I found one last night here in the states from a Florida seller, A few bucks more but that is ok.In the mean time I am looking at my current old dos programmer.It has it's own card that plugs into the PC. This thing was a work horse back in the day when I used it. I am looking through it to see if there are any chips listed that is compatible with the ram board. If so I should be able to build an adapter to accept the ram board like HighPrecision has shown.My old programmer is a Modular Circuits Technology 4 gang programmer. Pictures below. The software will run in demo mode on my Win 7 machine so I can show screen shots. Zip file of the program and all my old projects attached. The program executable file isEPP-04for those playing along. It opens a dos window and loads the program.A view of the main program window.Here you select the chip type. I always wonder if there is a way to add more types to this or manually add different chips.This window lets you change chip manufactureThis window lets you select programming algorithmHere is a pic of the old programmer.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 29, 2017, 05:04:35 pm
content: This morning I decided to do a bit of old school proto-typing.I made an adapter to plug in my old programmer (or any other programmer) and fixed it to accept the ram board. I will attached the pins with wires so it can e torn down and re-wired.So I need to learn a bit about the pins on the ram board and what each pin is doing.

author: Ian.M
author_rank: Super Contributor
timestamp: December 29, 2017, 05:30:59 pm
content: IMHO coding an Arduino sketch to interface to the board will be *FAR* easier than trying to hardware hack an old DOS era EPROM programmer to do so. However if your C programming skills are non-existent and you've never dabbled in any other procedural programming language, YMMV.Parallel EPROMs have separate /CE, /OE and Vpp pins and possibly a PGM pin. The RAM used on the ICOM memory board, and thus the board as a whole, doesn't. It has three control pins, one of which: WP, is the write protect for the lower 1/4 of the memory (via the 74LS32), which in a programming jig is disabled by tying it high, and can therefore be ignored. The other two are AD10, which drives the RAM's /CS pin, and /WR which drives the RAM's /WE pin.A RAM read cycle only requires /CS to go (or be) low. However for a write cycle, /CS and /WE must be sequenced low and released in the correct order to avoid a data bus conflict as there is no /OE pin. Its unlikely that any EPROM algorithm has compatible signal sequencing - you'll have to scope it and see, without the RAM board, but with 10K pullup resistors on the data bus. As some EPROM algorithms are interactive - reading back each location to check if its programmed then calculating and applying an overprogramming pulse (or pulses), that may not be good enough and you may have to test with a blank EPROM to see the full signal sequence.You must deal with the PGM voltage - at the very least it will need limiting to logic levels before input into the logic you will need to add to derive /CS and /WR from the EPROM signals. Also many of the EPROM programmer's algorithms will boost the supply voltage when programming, but over 5.5V is undesirable for the ICOM board.Hopefully you wont blow up the RAM board . . . .A universal programmer is a different and far easier beast to make an adaptor board for, as it will already have algorithms for programming NVRAM modules, which keep all signals within the 5V logic range, and with luck, one of its RAM algorithms will have the right sequencing and timings for a uPD444.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 29, 2017, 06:20:18 pm
content: I can already tell you mu coding skills are basically non existent. I have not played with this type of stuff since the 80's, a lot have changed since then. Even then I was not that good at it, I could copy and program from one chip to another.My TL866 will be here Thursday. So maybe I can adapt this board to it.As far as Arduino? I agree it may be the BEST way to go on this. But at the moment until I can learn a bit about it I am dead in the water. I have watched quite a few videos on it and looks very interesting.Only one video I found was close to really getting into eprom programming was from this guy below.Thanks for your information.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: December 29, 2017, 08:14:35 pm
content: Well, after a bit more fumbling around with the N2CBU programmer I now see why I am not able to read the ram board. I connected the logic analyzer to J2 (small connector) and looked at the LA and saw nothing while reading the chip. I did not look at clock and reset. But this does confirm that my parallel port is not seeing the ram board. So do not know if there is a IRQ conflict or the port is not working.I will have to investigate this more.

author: Co6aka
author_rank: Unknown
timestamp: January 01, 2018, 12:43:51 am
content: Which OS are you running the RAM board software on? And, are you certain of the address the parallel port is mapping to?

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 01, 2018, 02:32:17 pm
content: Quote from: Co6aka on January 01, 2018, 12:43:51 amI have tried windows 98 on a 386 machine and windows 3.1 on a 286 machine. No I am not certain. I have not used this type of stuff since the 80's. I did go in and change settings in the bios but same results. I connected the logic analyzer (above) to the 386 machine and when reading and writing from the N2CBU program I noticed nothing on the outputs. That really did not tell me much as if the port is not working or the program is not seeing the port. So I am out of options on that. I do not know how to do any further testing with it. Thanks.

author: CJay
author_rank: Super Contributor
timestamp: January 02, 2018, 06:38:03 pm
content: OK, back, lost a few days over Christmas with the flu or some such that confined me to bed between bouts of all sorts of nastiness.So, Buddy, if your programmer supports reading Dallas DS1220 Non Volatile RAM or ST MK48Z02 I'd consider using the settings for them so there's no chance of an 'accident' with VPP being applied to a RAM board but it might be easier with the arduino sketch.All the bita arrived so I can build a clone RAM board on breadboard for testing, over the next few days I'm intending to test and modify the code I have so I can read and display the content of the RAM board in a serial monitor window before writng it back to a blank board..

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 02, 2018, 08:00:28 pm
content: Quote from: CJay on January 02, 2018, 06:38:03 pmSorry to hear about he flu, that is nasty stuff. Hope you are feeling much better.So where I am today. I gave up on the thought of using my older eprom programmer. The algorithms are not right to be playing around with the ram board. Remember this thing is from the early 80's and no support for it anymore.So I do have my brand new Arduino in and trying to learn a few things with it.Today about 30 minutes ago my new Mini Pro TL866 programmer arrived. I loaded the software and reading old chips from the 80's. I just was able to read a TMS 27C128 chip that I loaded in 1988. It was programmed from the old programmer. I feel like I just reached the 21st century!Sounds great on building the unit. Keep us informed on your findings and thank you very much for the help.I built a proto type board to plug into the TL866 also. Crude but should work. It is designed after the board layout the High Precision posted.

author: AF6LJ
author_rank: Unknown
timestamp: January 02, 2018, 08:14:17 pm
content: What I am seeing in terms of the output doesn't make sense.There should be an address and a single byte of data since this ram unit is only eight bits.should look something like this.001 1A002 03003 F8....Etc

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 02, 2018, 08:20:59 pm
content: Quote from: AF6LJ on January 02, 2018, 08:14:17 pmYou talking about the screen shot above? That has nothing to do with the ram board. Was just a test to make sure the TL866 programmer was working. I read a TMI 27C128 chip. THe programmer was fairly easy to get working.I am trying to read a good ram board but getting nothing but FF"s back. I selected Dallas DS1220

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 02, 2018, 08:51:20 pm
content: Well well well.You guys are not going to believe this. I mean you probably want lol.I took HighPrecisions board and file and put it together.wait for it..............I programmed the dead board!Installed it in the radio and working like a charm.Beauty!So we now know we can program these boards with his modified files and a TL866 MiniPro programmer.A big thanks to HighPrecision and thumbs up to youNow to even get this more modernized we can now focus on the Arduino programming. That will make all this complete and give us several options for programming these rm boards.Big thanks and thumbs up to all you guys for helping this project along. You guys are the best. Now we can save the originality of these old radios.Video to come. Hope you guys do not mind being mentioned in it. But have to give applause to the ones that made it happen.

author: Ian.M
author_rank: Super Contributor
timestamp: January 02, 2018, 09:00:29 pm
content: Great. That will make it a lot easier to develop the Arduino Icom programmer sketch, as you can now preload the board with known contents, for the sketch to read, and also, when you add code to write the board, you can check it reads back as expected on the TL866.Start with LEDs (+ series resistors) on all pins you plan to use for the address and control lines and get them sequencing correctly with a delay in the loop before you connect the board the first time. When you connect the board, don't forget the 1K series resistors in the data lines to prevent damage if you get the /CS, /WR and data pin direction control sequencing wrong.

author: AF6LJ
author_rank: Unknown
timestamp: January 02, 2018, 09:35:18 pm
content: Quote from: Radio Tech on January 02, 2018, 08:51:20 pmThat's great!!

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 02, 2018, 10:20:51 pm
content: Quote from: Ian.M on January 02, 2018, 09:00:29 pmThat sounds like great advice. Will be fun learning how to do this in Arduino.Thanks for your suggestions.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 02, 2018, 10:22:09 pm
content: Quote from: AF6LJ on January 02, 2018, 09:35:18 pmAgreed Sue !Cannot believe how easy that was once I obtain the proper information and tools.

author: W2NAP
author_rank: Unknown
timestamp: January 03, 2018, 03:37:49 am
content: good deal it worked!

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 03, 2018, 01:24:22 pm
content: Quote from: W2NAP on January 03, 2018, 03:37:49 amThanks, I possible by the great help in this thread.

author: AF6LJ
author_rank: Unknown
timestamp: January 03, 2018, 01:57:48 pm
content: Now the next step is to hack the firmware to enable RX below 100 KHZ.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 03, 2018, 03:00:25 pm
content: Quote from: AF6LJ on January 03, 2018, 01:57:48 pmI have done a LOT of reading on the 745 over the last year. There is a bit of code located in address 000 that contains the upper and lower band limits for 160 meters. At least on the R71 receiver which uses the same ram board. From what I read by shifting a "1" to the left by one place it will change the lower band limit.Now that I can play write the board I can give this a shot and see. Worth a try.

author: AF6LJ
author_rank: Unknown
timestamp: January 03, 2018, 03:23:09 pm
content: Quote from: Radio Tech on January 03, 2018, 03:00:25 pmI'd like to see it carried down to 1KHZ.

author: HighPrecision
author_rank: Unknown
timestamp: January 03, 2018, 04:37:19 pm
content: Quote from: Radio Tech on January 02, 2018, 08:51:20 pmAgain, Thanks for your words Buddy !I wil add here the KiCAD files of the PCB and generated gerber files for production, please note that there is NO schematic in the project, only pcb.Good year 2018 to ALL !

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 03, 2018, 10:05:56 pm
content: Quote from: HighPrecision on January 03, 2018, 04:37:19 pmGreat, I am going to get a few boards made up.Not sure if I will make them myself or just send out for them. If so I will but a little bonus mention on themThan you very much.Next thing I want to do is break the code down completely. And yes been many years since I done that. I want o know what every byte in this does and what function it provides. This will get us closer to Sue's request on lowering the receive frequency. I really do not see a reason why the radio will not receive down further and looks like it is only firmware controlled.I have not started with the Arduino yet but we should be able to make a custom shield, so after the software is done the whole thing should be plug and play.You guys just do not know how excited all this has made me. I appreciate each and every one of you here.

author: Co6aka
author_rank: Unknown
timestamp: January 04, 2018, 12:48:24 am
content: Please post your 745 dump; if it's like the R71 it'll be obvious.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 04, 2018, 02:43:46 pm
content: I think we need to look at the modified file? I will try and play around with it today or tomorrow. Not sure if I can even get into the shop today due to recent snow storm. Also have to remember how to convert these files.

author: stj
author_rank: Super Contributor
timestamp: January 04, 2018, 04:59:05 pm
content: you know, you could replace the ram with a microcontroller and program it through usb?

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 04, 2018, 05:21:36 pm
content: Quote from: stj on January 04, 2018, 04:59:05 pmThat is very true yes. But if we are going to do that then best to just rip put the entire logic board and build one from scratch. This would do away with a lot of the limitations. It is something I like to do down the road.

author: AF6LJ
author_rank: Unknown
timestamp: January 04, 2018, 05:58:57 pm
content: The IC-745 is a very good performer for its day and for now.Two things could be done to improve the radio and bring it up to date.Replace the radio's controller subsystem.1. Eliminate the Matrix board, this board manages much of the front panel digital operations and supports the scan function.2. Replace the logic board with on board support for the front panel digital functions, and an 80 column display.A. Upgraded display that will support multi line data display.B. Upgraded synthesizer buss supporting a VHF DDS usable to 1HZ increments.C. Provide CAT interface with an instruction set compatible with the IC-756, allowing use with HRD. (Ham Radio Deluxe)D. PTT delay for safe amplifier operation. (for those who may not know this radio and other radios of its vintage are known for generating large RF spikes during T-R and R-T transitions. )E. On board keyer.The other issue that would add value to the radio was touched upon above. Replace the PLL board with modern DDS.While we are at it, a second LO upgrade would be in order.

author: German_EE
author_rank: Super Contributor
timestamp: January 05, 2018, 04:43:03 pm
content: And a pony

author: Co6aka
author_rank: Unknown
timestamp: January 05, 2018, 11:56:50 pm
content: For the R71, the frequency expansion is...30/31 = lowest frequency (factory is 100kHz)3B/3C = highest frequency (factory 30MHz)To change the lower frequency limit from 100kHz to 10kHz:Original - 000: 00F1FF1FF002FFFF000B59686800032005930005000000000100000030003000Modified - 000: 00F1FF1FF002FFFF000B59686800032005930005000000001000000030003000To change the upper frequency limit from 30MHz to 35MHz:Original - 000: 00F1FF1FF002FFFF000B59686800032005930005000000000100000030003000Modified - 000: 00F1FF1FF002FFFF000B59686800032005930005000000000100000030053000If merember correctly the transceivers had a similar entry for each ham band...It's been too many moons since the good-ol-days though, so I'm likely mistaken.

author: Diabolo
author_rank: Regular Contributor
timestamp: January 06, 2018, 08:13:07 pm
content: Hello,Thank you for your instruction and expertise.Regards.Diabolo

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 07, 2018, 01:19:02 am
content: Sue, Nice healthy list. Would really make for some nice improvement's to the IC-745.I really agree with the second LO upgrade. The stock circuit is bare bones at least to say about it.We have to get this in the works and turn this thread into a 745 makeover thread.German _EE,Got to include a ponyBTW, I need to email you. Just so many mails here. 3k this week.No idea why I get so many.Quote from: Diabolo on January 06, 2018, 08:13:07 pmYou are quite welcome.I am not speaking for myself but for those that have contributed so much in this thread.

author: AF6LJ
author_rank: Unknown
timestamp: January 07, 2018, 04:05:12 pm
content: My to-do list is ambitious to say the least.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 07, 2018, 06:07:44 pm
content: As of right now I am playing with some modified code. Working on the band limits. Where did you want to receive down to Sue.If the PLL stays lock we may have a winner.

author: German_EE
author_rank: Super Contributor
timestamp: January 07, 2018, 07:29:07 pm
content: As we can see the best way to keep warm is a workshop full of Hammarlund gear powered up in one corner whilst testing an Icom receiver to its limits on the bench. much more fun than turning up the heating.

author: AF6LJ
author_rank: Unknown
timestamp: January 07, 2018, 08:03:27 pm
content: 1KHZ If you can do it, I'll get a battery for the ram module I have here and have you program it.

author: AF6LJ
author_rank: Unknown
timestamp: January 07, 2018, 08:04:32 pm
content: Quote from: German_EE on January 07, 2018, 07:29:07 pmYes it is...Almost as much fun as chewing the rag with friends while the Heath SB-101 and SB-220 are running.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 07, 2018, 08:24:00 pm
content: Quote from: German_EE on January 07, 2018, 07:29:07 pmOh yes, that should do the trick. Have to fire up the Johnson's and the Swans also. It is a frigid 18 degrees F here at the moment.Here is something I have not seen since I was a kid here. Went to the dump a moment ago and the roads here are still under 3-4 inches of ice and snow. I then crossed the river bridge and snapped this picture below. I have not seen that river frozen over in many years.I am going to call it a day here in the shop. Been running back in and out of the house helping the wife with the grand kids.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 07, 2018, 08:26:37 pm
content: Quote from: AF6LJ on January 07, 2018, 08:03:27 pmCool, I am shooting for 0 starting frequency and see where it goes from there. May be tomorrow evening before I can go any further.They say it will e a toasty 44 degrees tomorrowI am going to get some more batteries and weld some leads onto them myself.

author: AF6LJ
author_rank: Unknown
timestamp: January 08, 2018, 02:02:35 am
content: Quote from: Radio Tech on January 07, 2018, 08:26:37 pmSounds good, looking forward to seeing your result.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 08, 2018, 05:08:12 pm
content: If all goes well this evening I will try the new file out.So frigged cold here. Should warm up to mid 40s. Will be the first time out of freezing.The file is already to be loaded into the ram board. We will see what it does. may record and upload.

author: AF6LJ
author_rank: Unknown
timestamp: January 08, 2018, 07:00:57 pm
content: Quote from: Radio Tech on January 08, 2018, 05:08:12 pmYou guys are getting tossed in the deep freeze back there.I wish we had some of that out here.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 08, 2018, 11:21:58 pm
content: Quote from: AF6LJ on January 08, 2018, 07:00:57 pmI wish you could have itIt has not been this cold in a long time. It finally got out of freezing today. Upper 40's. By this coming Friday low 70's. Woohoo

author: AF6LJ
author_rank: Unknown
timestamp: January 09, 2018, 12:01:44 am
content: Quote from: Radio Tech on January 08, 2018, 11:21:58 pmIt sprinkled here today for a time, supposed to rain tonight.Rumor has it we may get an inch or more./Sue is not holding her breath.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 09, 2018, 12:17:16 am
content: Now for the good stuff. Although tempos are climbing it is still 40 in the shop. Takes too long to get heat up. So here at the bench in the house I started playing with the modified bin file. I really need to be doing this in the shop where all the notes are.I have some upper limit now. Radio will receive all the way to 30.9999 then receives drops out at 31 MHz.The limits are really set high on the top end. As you can see the display is showing well over 55 MHz.I got tired of spinning the dial so that is where I stopped at. The "Band" button does not let you go through the upper portion so you have to use the "TS" button. Not really sure just how high the display will read.No luck on the bottom end yet. I have to look at this more. My radio only goes down to 1.800.0.Now this rig has a mod in it I need to remove. I have never modified a 745 to go outside the band. There is a switch in the rear that is stuck on the "ON" position. Possible this mod is causing an issue as well. As far as I can tell there is two wires going to it then over to the RF board. This looks like a transmit enable mod for out of band. .While in General Coverage mode it will tune all the way down to 1.6 before receive falls out. This tells me we have to do some work in the VCO area if we are going to her anything down there. As much room that is in the radio I may build up a separate VCO section for this and switch it in with a diode matrix. But that is for another time. But I am sure a simple tweak of the VCO will bring the bottom end up a bit, just do not know yet what will happen on the top end on that band.Anyway this is fun and may wait till the week end to really get into this a bit more.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 09, 2018, 12:28:11 am
content: Quote from: AF6LJ on January 09, 2018, 12:01:44 amI thought it was always sunny in Kaliforny. At least the song said it was

author: AF6LJ
author_rank: Unknown
timestamp: January 09, 2018, 12:08:23 pm
content: Quote from: Radio Tech on January 09, 2018, 12:28:11 amNever use to be always sunny here..Since the population explosion of the 70s and 80s, The People's Republic of Kalifornia has a large heat island along the south coast that does effect the weather...We use to get 2 feet of rain here every year, snow in our mountains every year and the state population was somewhere south of 14 million. Now there are more people than the country of Canada. It is not such a nice place to live.Always hot, dry the air is dirty and the cost of living out of sight.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 13, 2018, 05:56:11 pm
content: Was 70 here yesterday and 50 here today but temps are dropping.I want to expand on this thread a bit more and add more modifications to the Icom radio.The IC-745 is called a ALL MODE radio by ICOM. But they did not include AM transmit.This week end I have started looking at the AM transmit mod listed by Paul N2FAN in 2003.This was done on a word processor of the day and can be a bit confusing to the untrained eye.I am working on a modern version of the mod. Will take me a while to get this done, installed, and tested.It really is not a lot of work to do the mod. I am attaching the documentation here. along with the original link in case it vanishes from the internet.http://n2fan.org/ic-745.htmlHere is the original text:14 Jan 2003 @ 20:07:31 UTCSubject: ICOM IC-745 extend xmitSubmitted to QRZ.COM on 06-1999 7 years, better late then never!73 Paul N2FAN (n2fan@glensummit.com)REVISIONS:---------------** Updates and Fixes Submitted 05/2000 **Info: Some miss labeling and updates.** Schematic Scan and Labeling 05/2000 **PJH 5/2000=========================================================================----- MODIFY FORUM appended at 23:17:57 on 92/04/27 GMT (by PAULH at POKADD6) -Subject: /********* AM TRANSMITTER ENABLE FOR THE ICOM IC-745 **********/Intro:After returning home from purchasing a used (but in good condition)ICOM IC-745, initial check out revealed the transmitter did not function in AM transmit mode. A look and the owners manual revealed: "AM Receive Only" What!!!??? This is supposed to be an ALL MODE RADIO!In reality the words used were..."ALL BAND HF RADIO"After analyzing this perplex situation I came to the conclusion ICOM must have been doing their part in trying to save precious spectral bandwidth by not incorporating AM transmit in this particular model.No one really utilizes AM mode these days (including myself) but this radio has every mode ever conceived and to leave AM transmit out really aggravated me!Below is the Mod of Mods for IC-745 owners:(All Modifications administered to the "MAIN UNIT" board located under the top cover of the radio.)(Except for R21 Removal on the logic board for the Power Mod.)Parts list: ------------8 pin diodes. Factory Diodes are P/N 1SS53. 1N914's are fine.3 10k resistors 1/4 watt.1 NPN TO-92 pkg. switching TX, 2N3904 or equivalent is fine.Source Voltage Terminology and Locations:-----------------------------------------R8 = 8 Volt Receive Mode SourceAM8 = 8 Volt AM Mode SourceFM8 = 8 Volt FM Mode SourceCW8 = 8 Volt CW Mode SourceRY8 = 8 Volt RTTY Mode SourceUSB8 = 8 Volt USB Mode SourceLSB8 = 8 Volt LSB Mode Source______________________| |"J7" Pin #1 | O O O O O O O O O O | Pin #10Main Board |_____________________|| | | | | | | | | |--- --- | | --- ---A R U L C FM Y S S W M8 8 B B 8 88 8-----------"J21" Pin #1 | O O O O | Pin #4Main Board -----------| | | |-------R8/***************************** THE MOD *********************************/1) Pull up the anode end of Diode D44. (located by TX Q39)Build the additional circuit below. This will enable the B+ to theproduct detector and 9 Mhz BFO oscillator.The 9Mhz osc will now be working for AM transmit as well as BFO Rec.Co to AM8 (Where the Anode of D44 was)\\| B 10K 1N914|------\/\/\/\/-----|<-----o to R8/|to R239 o----|<----/ 2N3904 or EquivalentD44 E2) Remove R66. (Located by TX Q13)Relocate and solder one end of R66 to the bottom of the board.(The end that goes to R23 and R30)(The schematic shows a "BREAK" in the land. By removing theresistor from the PC board this simulates the break.)Solder two 1N914's to the other end of R66. (Cathode ends of course)Note: All pin assemblies will be connected on the underside of the MainUnit PC board.This is part of the Mode selection process, and turns off themike shunt in AM mode. (So audio can pass to the Balanced Modulator.)to R23 & R30 o-----\/\/\/--:----|<----o Anode to CW8|R66 :~---|<----o Anode to RY810K pair 1N914's (add)3) Solder one 1N914 diode (Cathode end) to the cathode connection of D15(by TX Q19) under the board. Connect the anode to AM8.This will enable the B+ to the Mic Amp stages and VOX ckts.to R31 (10K)^||___break___| D15|------------|<----------------o Goes to 8 Volt LSB Source|------------|<----------------o Connect to AM8 Source|| 1N914 (add)to R100 (100 Ohms)4) Remove R31 (Located by TX Q8)Relocate and solder one end of R31 to the bottom of the board. (The end that goes to R30 and the base of Q8)(The schematic shows a "BREAK" in the land. By removing the resistor from the PC board this simulates the break.)Solder Three 1N914's to the other end of R31. (Cathode ends)Tie the Anode ends to LSB8, USB8, FM8.Function: This portion of the mod will turn Q8 off in the AM mode to unbalance the balanced Modulator (IC1) for AM full carrier operation.Co 3 1N914's (add)\(Q8) \| B R31 |--|<-----o to LSB8Bal/^Bal |---------\/\/\/\/--|--|<-----o to USB8switch /| | | |--|<-----o to FM8for / | |IC1 o \ \E / /R29 \ \ R30/ /| | R's=10K's___ |_ o5) Remove R24 (Located by TX Q7, "Mike Shunt Ckt")Solder a 1N914 Diode (Cathode end) into one of the pc holes that R24 came out of. (The one end that connects to R65 by Xtal X1.)Tie the anode to AM8.This will enable the 9 Mhz CW xtal to generate the correct centerfrequency for AM.--o-||||--->|-o-- |X1 \/R64 \ 1N914 (add)10K / R65|-----\/\/\/\--------------|<------o AM8___ 220 |C44 ___ ---|<---o to CW847pf |--- D13-6) AM Power Level Adjust (optional)Due to the duty cycle requirements of AM, output power of 40/50 Watts RMS should be the limit. Use the Front panel RF adj to reduce the output from 100 Watts or do the following:A) Connect a small 22 gauge (or so) wire from AM8 to the anode ofDiode D26 by TX Q20. Add a series 10K resistor.AM8 o------\/\/\/\-------------------- o-->|-----o to Q2010K | D26|__________________________| oAdd this o S1|B) Set the 50/100 Watt power switch (S1) in the 100 WattPosition if you desire 100 watt operation of SSB,CW,RTTY.C) Adjust R116 (in AM xmit mode) for a power output of 40 Watts RMS.D) What were doing here is using the 50 Watt low power ckt as the AMpower adjustment control.Paralleling another connection to FM8 will allow FM to be reduced insimilar fashion (as well as AM) instead of the factory 100% dutycycle.FM8 o---->|-------/\/\/\/----o1N914 | 10K |AM8 o---->|------- o-->|-----o to Q201N914 | D26oo S1|Note: When 10 Meters is selected port 28M (pin 47,IC3 on the logicunit) goes high, this turns on pin diode D27 on the main unit.This ultimately turns on the 50 watt (low Power) ckt allowing onlylow power operation from 28-30 Mhz?I don't know why Icom did this? My guess is for 10 Meter FMoverlooking the fact SSB/CW will be running reduced also.You may want to remove R21 (10K) on the logic board to remedy thissituation. After R21 is removed you can limit the duty cycle onAM & FM as follows:FM8 o----\/\/\/\----->|----10K | D27 || |AM8 o----\/\/\/\----->|-------o to Q2010K | D26|oo S1|Low power Adjustment R116 will now adjust output power for FM as wellas AM.OPERATION/CONCLUSION---------------------The above AM/FM power mod is recommended. Higher power levels(Greater then 70/80 Watts RMS) result in severe distortion ofthe AM output signal.Surprisingly the audio quality is quite good on AM xmit. (40/50 Watts)Several on the air discerning ears concluded the fidelity was quiteacceptable. (Even from the Johnson Viking Guys on 3.880 (+-))For you skeptics wondering how an AM signal can sound acceptablethrough a 3Khz wide 455Khz SSB filter....................A quick turn to the schematic on the IF board depicts filter F-I1.(Ceramic filter CFW-455IT) This filter is a 6Khz wide ceramic filterused for AM receive mode. After the completion of the Mod this filterwill be used for AM xmit also, by default! >>> It's in there!! <<<(Wasn't that a commercial once?)Filter F-I2 (ceramic Filter CFT-455K14) or the optional FL-44A(SSB filter) is in operation for all other modes except FM.The optional FM board employs it's own filter arrangement.That's it. Your all mode radio is now all mode!73 Paul N2FAN*05/2000I have scanned the Main Board and Logic Board to depict the electricalchanges made to the circuits. I tried to nicely re-label all the changesusing VISIO technical, but I ran into some offset problems.The hand written changes will have to do for now until I can get Visio towork right.If you have any questions about this Mod feel free to ask via e-mailonly (I'm hard to get a hold of) e-mail = n2fan@glensummit.comThis is not an easy cut the wire mod, you will need to have some goodelectronic technician skills. PhD's forget it! ......This Mod works, I still have my IC-745 after 8 years!73 and Good Luck!

author: AF6LJ
author_rank: Unknown
timestamp: January 13, 2018, 06:16:25 pm
content: Cool...I have some new (to me) gear.Look for tear down pics here in this sub form in the near future.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 13, 2018, 06:34:32 pm
content: Quote from: AF6LJ on January 13, 2018, 06:16:25 pmGreatNew used gear is always fun

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 15, 2018, 01:08:50 am
content: Well, the AM transmit mod works

author: AF6LJ
author_rank: Unknown
timestamp: January 15, 2018, 04:46:46 pm
content: Saw your video it was good.

author: German_EE
author_rank: Super Contributor
timestamp: January 15, 2018, 06:01:06 pm
content: Nothing wrong with a bit of Ancient Modulation on Top Band.Looking at the video most of the modifications seem to involve adding extra diodes to the connector which supplies 8V depending on mode. Rather than use individual diodes I wonder if the mod could be neater using a small PCB with all the diodes added as surface mount devices? I guess it would be about the size of a large postage stamp.Any idea of the modulation depth or does that depend on the Microphone Gain setting?

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 15, 2018, 09:33:33 pm
content: Quote from: AF6LJ on January 15, 2018, 04:46:46 pmThanks Sue, You know that modification has always looked a bit intimidating to me. And is why I have never attempted to do it. But after spending Saturday reading over the material I thought to myself this is really nothing to it.I will say I spent about 5 hours on this modification. I recorded it as I went along. The was no planning ahead or reshoots. After all said and done I had about 40 minutes of usable video.What really tied me up the most is I cannot find my original service manual. I thought I left it at work but was not there. The online PDF files are useless in locating the parts. Also there is no pin one location for J7 in the PDF. This forced me to search the board for each component.Quote from: German_EE on January 15, 2018, 06:01:06 pmYou got it, just moving the 8 volt lines around to do the task.So it looks like we are thinking alike!This was the first time I have ever attempted the AM mod on this rig. After doing it I now see more clearly as to what is going on. Today while at work I am think like a marketing sales guy. How can I make this into a product? Make it so anyone can do this mod? That's when it dawned on me that it all can be done on a small pc board with surface mount.The board would be so thin it could be attached to the bottom of the radios main board. Then have multi-color wires to attach to the board after the component's are removed. I would even have D44 completely removed and add a surface mount diode for that on the mod board. I would also have to incorporate the AM power mod to keep folks from running the AM carrier up to the point of melt down. We do not want the unmodulated carrier to be overNow I just need to get better with circuit board programs and do it.I have not done any hard in-depth testing on the AM modulation yet. But looking on the scope and a nearby receiver the audio quality sounds really good, the fidelity of the signal is decent. Once I get everything sorted out I will do some further testing and see just what this rig will do on AM.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 23, 2018, 04:49:00 pm
content: Just an update on the AM transmit audio.I am really impressed with the quality of it. Sounds very good. I have not yet ran the numbers on it but in all it is decent.Will do more when I get time. Been really busy here the past few weeks.I need to find a easy to use circuit board design program. I do want to convert this AM mod to a single pcb mod.So all the user has to do is remove the components and wire in the board. Should make for a nice clean install.I will do the proto type myself then see about getting boards made from a supplier. Along with Highprecisions adapter board.

author: AF6LJ
author_rank: Unknown
timestamp: January 23, 2018, 05:35:58 pm
content: This should be interesting...I have also been busy and have a number of projects on hold..

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 23, 2018, 09:55:31 pm
content: Quote from: AF6LJ on January 23, 2018, 05:35:58 pmI can only imagine Sue. With your knowledge I bet you get a lot of folks calling, emailing and wanting answers. Heck I have even asked you a few over the years.Seems the back log of projects keep on getting bigger. Seems I am doing more repair work these days than what I intended to do. Folks are emailing me daily and I have to tell them 3 to 4 months before I can get to it.Don't get me wrong, I love the time I spend on radio repair and picking up a few extra bucks here and there is nice. But it takes all my free time up. I never thought doing a few YouTube videos would lead to this.I am trying to make the Icom 745 stuff my biggest priority at the moment. As soon as I get the AM mod proto-type board done I will send you one to try out. Pauls modification posted above is really not that hard, just looks complicated. The believe board I want to build could be installed in under 20 minutes.I hate rushing life but retirement needs to get here sooner.

author: AF6LJ
author_rank: Unknown
timestamp: January 23, 2018, 10:25:01 pm
content: We have to install the battery back up for our club repeaters on Thursday. I have to make sure I have all my ducks in a row on that project and also I have to modify the programming in our repeater controller. (I have to work on that tomorrow. )After that....There is a Yaesu FT-847 I need to look at for a ham.Then I get to work on the club newsletter, only after that I get to return to my projects.

author: Gaz
author_rank: Newbie
timestamp: February 05, 2018, 07:40:47 am
content: Hi all,Great discussion and solution to a mutual problem. I am a relatively recent addition to the ham community and have obtained an IC-271H. The previous owner wasn't able to confirm the age of the backup battery, however, the radio has been re-capped and is in excellent condition and working order so I'm looking to ensure that it remains operational for a long time to come.I am by no means an expert in Arduino, much less programming/reading memory chips. However, my VK version of the trx (memory #06) doesn't didn't come with onboard CTCSS encoding, nor does it have the optional encoder/decoder fitted. I have managed to use an Arduino and adapt a Direct Digital Syntheses (DDS) sketch to generate the 'sub-audible' tones necessary for repeater access whilst also interfacing the existing (already functional) 6 bit encoder data bus to select different tones without the need for external modifications. The duino UNO I'm using is overkill for the task but I am also planning on utilizing it as a CW keyer and now I see the possibility of also addressing the volatile memory issue.To that end, here is a link to a timely article in a relatively new Aussie magazine regarding using Arduino to read and program PIC uPs. It should provide some clues for those here investigating using duino to access the ICOM memory boards:https://diyodemag.com/projects/arduino_pic_programmer73GazVK2GTS

author: Radio Tech
author_rank: Frequent Contributor
timestamp: March 03, 2018, 01:40:26 am
content: Quote from: Gaz on February 05, 2018, 07:40:47 amThanks Gaz for that post.Sorry it took so long for me to reply. Been quite busy here over the last few months.I will take a look at that link and see what I can learn. Should be a good read as I know nothing about the Audrino let alone programming with one. Good thing is my programmer that I bought is working quite nicely. But would like to continue this thread further.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: October 28, 2018, 11:01:46 pm
content: Been a while since I done any updates on this thread.I have some programmer boards being produced by JLCPCB in China.As soon as they arrive I will be posting further testing on the 745 ram board.Big thanks to all that have contributed to this project.

author: AF6LJ
author_rank: Unknown
timestamp: October 31, 2018, 12:56:51 pm
content: Good Video Buddy, watched it yesterday.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: October 31, 2018, 04:08:30 pm
content: Quote from: AF6LJ on October 31, 2018, 12:56:51 pmThanks Sue,The boards should be here Friday. Than I will populate them and do some testing. Really looking at making a production run on them. Not sure how well they would sale. May do several packages, adapter board, adapter board plus programmer. Not sure yet.On another note I am also designing a very small pcb that is in cased in epoxy. All surface mount components. Consist of 9 resistors, one diode, and one transistor.Mount board under main board, remove three resistors and one diode, then wire up the harness.You now have AM transmit. Quick and easy modification.

author: AF6LJ
author_rank: Unknown
timestamp: October 31, 2018, 10:19:40 pm
content: Quote from: Radio Tech on October 31, 2018, 04:08:30 pmThat will be good.looking forward to seeing the AM mod PCB.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: November 03, 2018, 01:01:23 pm
content: Great.I have been playing around with several pcb programs for the prototype board. I really need to learn how to use them things.This should really make the AM transmit modification a lot smoother than it is. It takes several hours to do it the way it is presented in the video.With this mod you remove a diode and three resistors. Connect the 14 wires and done.I did a rough layout of the schematic and pcb layout for through hole components. But I really need this done for surface mount. It will make the board much smaller.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: November 05, 2018, 01:10:37 pm
content: Got the boards in from JLCPCB this week end.Not bad at all. Bit of an interference issue with the mini pro programmer but that is ok.

author: am
author_rank: Newbie
timestamp: July 27, 2019, 01:25:28 pm
content: Hello all,N2CBU´s circuit just worked fine with my IC-745 and IC-271 (find some photos attached). The "essential" requirement was to find a mid-age PC working on genuine DOS, and to remark ALL drivers in config.sys and autoexec.bat, also disable all items in the BIOS menue-including hardware devices/ports/controllers. Only the LPT board was configured.It seems like to transform this issue back to the early Nineties-but it works. I´m sure that it should be able to read/change/write the memory contents also with an Arduino etc-using today´s PCs.73 de Armin/OE7IMI

author: randman80
author_rank: Newbie
timestamp: August 13, 2019, 09:42:23 pm
content: Well I picked up a non working IC-751 and, in mid repair, I decided to replace the battery on the ram board....No, I didn't look on line FIRST!... you can guess the rest. Replaced the battery and killed the receiver!I decided to "fix" the board. I found the schematic on line and a copy of the ram contents. All I needed was a programmer.The Arduino Nano was just the ticket. I ginned up some code and built a circuit board to connect the memory board to the Nano. It is a completely passive interface. The Nano cost was about $3. the rest was a small prototyping pcb , a couple of headers and a 30pin socket for the Nano.(The LEDs were just for testing and debug) I just plugged the ram board onto the new board, powered the programmer up and a couple of seconds the ram board was restored.Happy to share if there is any interest. Oh, it worked great and the receiver is functioning....Now if I can the the transmitter to light up,UPDATE: attached is the Arduino code. Copy and paste it into the Arduino editor (FREE ). Of course you will need to program the Nano using the Arduino IDE (FREE) ..piece of cake.The wire list is all you need to wire it. It is a pin to pin wiring.When you are all done, just plug in the Ram board , then connect the Arduino to a usb port and in a few seconds it will be done. The code will start over in 60 seconds so you have plenty of time to pull the USB connector then remove the Ram board.The 512 BYTES are in the Loooooong string called codeString. You can make the changes some folks have submitted to extend the frequency range of the radio, I chose not to. It is just a few bytes. I don't have a copy of the changes in hand. They are out there.Note that the spacing between the two connectors on the Ram board as NOT on .10 It is off by .05. I managed to bow the header pins on my breadboard and made it fit. Also note that you need long header pins. I just soldered the headers to my pcb, then went back and heated each pin on the bottom of the PCB with my soldering iron and pushed the pin till it was flush with the bottom of the PCB. That was enough, just.Best wishes and good luck.....Chuck KX4SB

author: TheSteve
author_rank: Unknown
timestamp: August 13, 2019, 11:08:08 pm
content: Nicely done!Please do share your code/schematic - I am sure others will benefit down the road.

author: Marcony
author_rank: Newbie
timestamp: September 05, 2020, 08:06:04 pm
content: Hello everyone,I recently got an Icom IC-745, with dead RAM battery.After battery replacement, I tried N2CBU programmer, but without success.Also, I tried Arduino programmer from randman80 - still no success (I've replaced HEX values for IC-745).Wiring in txt file (751ProgrammerWireList.txt) says that Arduino pin D11 goes to RAM board A0.But, when you look at the Arduino code (Arduino751ProgrammerCode.txt), you can see that pin2 (D2) goes to A0: "pinMode(2, OUTPUT); //ADD 0".Tried both solutions, still nothing.Did anyone else have success with this programmer?Is there a way to read the content of RAM through Arduino?

author: Mildi
author_rank: Contributor
timestamp: September 20, 2020, 04:03:42 pm
content: For the N2CBU programmer, you need a computer with OS DOS or Windows 95. With direct access to the LPT port.I used Xgpro TL866 II Plus with an adapter board from this topic.I chose the Dallas DS1220 microchipEverything is programmed perfectly.Check that the code placement in the program matches the adapter. If the lower halves of the byte are unsoldered to the data bus, then the code in the program must be in them, any older ones.

author: seb21051
author_rank: Newbie
timestamp: September 25, 2020, 01:54:10 pm
content: Hi Everyone, new member here.I 'm retired and recently decided to try my hand at Ham radio. I picked up an IC-745 on ebay, it should arrive in next week. In the meantime I have been reading up on it.I have thoroughly enjoyed reading about this radio and find the collective wisdom on this board to be fascinating!With that in mind I wanted to ask Buddy if he's selling his programmer and AM conversion kits yet?Regards,Stefan.

author: Mildi
author_rank: Contributor
timestamp: September 26, 2020, 04:03:05 pm
content: I am looking for the original memory dump of Icom Ic-471, in any format (screen, bin, hex). .We need information on the numbers on the ram-boards of the icom ic-471 A / E / H transceivers.Presumably:icom ic-471 A - #05icom ic-471 E - #10 or #4icom ic-471 H -??In which devices are there ram-boards with numbers: # 9 # 10 # 13?

author: DL8EBD
author_rank: Newbie
timestamp: September 28, 2020, 07:37:28 am
content: Hello, Mildi,I have the RAM content of the IC-471(Version E 430-440MHz) as HEX file.Read out with the adapter board as shown in post #171 from user "Radio Tech" - and a GALEP programmer (I chose DS1220)Where can I send you the HEX file?btw: I don't have the RAM board number anymore because the battery and therefore the sticker has been changed before.I also have the files for the IC-271 and IC-1271 too73Thomas, DL8EBD

author: Mildi
author_rank: Contributor
timestamp: September 28, 2020, 04:11:42 pm
content: Hello Thomas.Can be sent by email: ***********************.If you have ram content IC-271 and IC-1271 read from original boards, then I would be very grateful to you for them.Now I can make the contents of the ram board for any device of this series. But there are some controversial data that differ slightly in the content files of the RAM boards.I would like to compare with the original and understand the nuances.In the screenshot I marked these areas, for example.Some of them are completely incomprehensible.For some there is an assumption, but there is no way to check.Complicating further is the lack of a service manual from the IC-471 in the network.

author: DL8EBD
author_rank: Newbie
timestamp: September 28, 2020, 05:10:33 pm
content: E-Mail is on the way

author: Mildi
author_rank: Contributor
timestamp: September 28, 2020, 05:41:05 pm
content: Thanks. Received.

author: UR4MDE
author_rank: Newbie
timestamp: June 05, 2021, 04:11:39 pm
content: Good afternoon, help me to flash the IС-745, I didn't quite understand how to remake the firmware file for the TL-866 plus programmer. Please share the prepared file. I burden the board with an adapter from this forum. Thanks in advance to everyone for such a great programming job. Best regards Denis UR4MDE .

author: BG9ICN
author_rank: Newbie
timestamp: June 12, 2021, 03:53:14 pm
content: Hello Thomas.Could you send me an IC-1271 RAM file?My email: BG9ICN@hotmail.com.I use a old programmer to operat it as EEPROM mode. It's works well.73

author: Igloo
author_rank: Newbie
timestamp: June 30, 2021, 11:57:20 am
content: Hello is there anybody that have IC-471 ramfile that works with TL-866 programmer.

author: UR4MDE
author_rank: Newbie
timestamp: July 03, 2021, 06:05:56 pm
content: It feels like the forum is dead , with the answers somehow not thick. Someone please publish an archive with the firmware files of the transceivers for the TL866 programmer .Такое ощущение что форум умер , с ответами как-то не густо. Кто-нибудь пожалуйста опубликуйте архив с файлами прошивок трансиверов под программатор TL866 .

author: Mildi
author_rank: Contributor
timestamp: July 04, 2021, 09:52:52 am
content: Take the usual firmware 741 or 745 in the n2cbu format (available on the Internet).Use the .hex editor or utility to remove the even bytes from it.Get a 1KB file.Using a .hex editor or utility, increases the size to 2KB.Fill the second kilobyte with data from the first kilobyte, so as not to worry about how the A10 address line is routed.The file for tl866 is ready.

author: bejoysat
author_rank: Newbie
timestamp: July 09, 2021, 04:53:00 pm
content: Quote from: randman80 on August 13, 2019, 09:42:23 pmThanks a ton! The program worked flawlessly and I was able to restore a RAM board for IC751 which was left unused for 30+ years.73VU3BOJBejoy

author: Mildi
author_rank: Contributor
timestamp: July 11, 2021, 08:44:19 pm
content: Thanks to Igloo, it was possible to restore the original ram board dumps except for ic-1271 (there are 4 versions, I know only two versions).The files have been redesigned for different programmers.All data in archived.PS: Для русскоговорящих Просьба не дублировать на CQham и QRZ....

author: BG9ICN
author_rank: Newbie
timestamp: July 13, 2021, 03:50:21 am
content: Thanks your work.I have an IC-1271(not A or E), and the number of RAM board is #14.I didn't have another RAM file. Now it only works on 1260MHz-1299MHz.Maybe I flash a wrong version.

author: Mildi
author_rank: Contributor
timestamp: July 13, 2021, 07:50:38 am
content: IC-1271 (not A or E), this is guess Japanese version of RAM # 14.Should work in the 1260-1300 range.IC-1271 (A or E) have 3 versions.Europe, America, Australia RAM # 15,16,17They work in the range of 1240-1300.Perhaps the IC-1271 (not A or E) differs in hardware from the IC-1271 (A or E), I don’t know, I only have a service manual from the IC-1271 (A or E) and I cannot compare it with the usual one.Since I could not find all four versions of RAM board dumps and service manual from IC-1271 (not A or E), I did not examine the contents of these RAM boards and did not compare them .If you have the original RAM board # 14 dump, I would be glad if you published it.I am attaching two versions of the RAM board dumpThey are in different formats:in N2CBU format from IC-1271 (not A or E)in format for TL866 from IC-1271E

author: fedecortes1
author_rank: Newbie
timestamp: September 29, 2021, 11:15:40 pm
content: Hi everyone. First of all, I thank Lex for sharing such valuable information with us. I would like to know if you can send me the file that I should use to reprogram an ICOM RAM BOARD from an IC 751A. I have built an interface whose diagram is based on an IC CD4040 + a 5V regulator and using the ICOM-RAM.EXE program which indicates that the recording process has been carried out correctly, when reading the ICOM RAM again I see that it is indeed the same It contains information, but when installing the board in the IC 751A the equipment does not work correctly, I would like to try it with a different .BIN than the one I have if you can send it to me. Thank you again for your attention. Greetings from Argentina

author: 4K6EH
author_rank: Newbie
timestamp: November 02, 2021, 09:23:57 am
content: Hello, I have an icom745, its RAM has been erased. I tried to program it with TL866 as you explained in the video. Even though it says "Programming succes", when I read the RAM it seems to be empty. It also doesn't work when I plug it into Icom.

author: Mildi
author_rank: Contributor
timestamp: November 02, 2021, 08:05:49 pm
content: What firmware did you use?If in your firmware the second kilobyte is filled with FF or 0F, then when the second kilobyte is written, it is written over the first.The first and second kilobytes must duplicate each other, or the firmware must be contained in the second kilobyte.

author: wirstinson
author_rank: Newbie
timestamp: November 03, 2021, 08:06:37 pm
content: First post. I thank the people who contributed by publishing the programming data of the ex-314. I have successfully programmed 3 ex-314 with the programmer published by N2CBU on a Compaq p3 200Mhz windows 98 per Lpt port, 2 from Icom IC-751, IC-751A and one Icom IC-271H.

author: hostile
author_rank: Contributor
timestamp: August 17, 2022, 07:43:59 pm
content: Updated 8/21/22updated RAM14 array sizeUpdated 8/20/22Now includes all of the memory dumps from Original_icom_ram_multi_format archive from this topic.Expanded on Randman80 Arduino code. ThanksUsed on IC-745Made it easier for myself to follow, others may disagree.Select the RAM to be programed from the #defines in headerChanged the pins to re-definable constants at beginning of code.- Change these to match how you jumper the Arduino to J1, J2Changed the WR CS timing to help avoid clashes.added dumping of memory and verification.use the Arduino console with 115200bps.commands are single letters with enterp, programs, reads, verifiesd, prints memory to consolev, verifies last dumped memoryc, clone memory, requires hot-plugging ram module with Arduino onThere is a custom slot for the RAM defines. you can dump memory and copy paste it there, to do many clones without hotswapping

author: Mildi
author_rank: Contributor
timestamp: August 20, 2022, 09:48:12 pm
content: Very well.It remains to be done using the free ports of the Mega 2560: Selecting the firmware number (dip switches or jumpers). Start read/write button. Indication of reading / writing and the end of reading / writing. Add firmware for 1271.And there will be a completely ready, stand-alone programmer.

author: hostile
author_rank: Contributor
timestamp: August 20, 2022, 09:54:19 pm
content: Quote from: Mildi on August 20, 2022, 09:48:12 pmI was afraid to add additional inputs from the Mega2560 so it would be compatible across all the arduinos. Would be pretty easy to change it over to that if someone wanted it to be a complete standalone, let me know if that is something of interest. You get the information on when write is done and verification, would also be easy to toggle an led based on the pass or failure.I will add the 1271 firmware you supplied of not A or E as soon as I finish up some work.

author: Mildi
author_rank: Contributor
timestamp: August 20, 2022, 10:32:30 pm
content: I just suggested additions that will turn this version into a functional analogue of the original "icom EX-428 ram writer" programmer.

author: hostile
author_rank: Contributor
timestamp: August 20, 2022, 10:35:57 pm
content: Quote from: Mildi on August 20, 2022, 10:32:30 pmAnd good suggestions if someone would use them, do you have an atmega to test? I could add the extra features in the code, but behind on work and would be a while for me to setup hardware to demo the LEDs and toggles switches. would probably make it separate from this code so others could still run it on the smaller Arduino versions. I added your supplied firmware as RAM14.

author: Mildi
author_rank: Contributor
timestamp: August 20, 2022, 10:44:36 pm
content: Thank you.I'm sure my fellow radio amateurs will like it.And your work will be in demand, and people will thank you.

author: hostile
author_rank: Contributor
timestamp: August 21, 2022, 10:16:22 pm
content: Updated 8/22/2022Had an issue with the way I was pulling ram data from the program memory spaceHere is a standalone version that I tested the additional inputs with digital IO controller.4 pins for RAM selection, 3 LEDs (Programming, Pass, Fail)1 Button to start programming, can still be controlled and viewed output in console.https://youtu.be/Zlx7NylAdQw

author: Mildi
author_rank: Contributor
timestamp: August 22, 2022, 06:48:17 am
content: Thanks a lot!Ideal!Already ordered a breadboard for installation on 2560.When I return from a business trip, I will repeat the apparatus.According to Murphy's law, the Icom battery runs out when there is no PC nearby to flash it...

author: rz
author_rank: Contributor
timestamp: August 30, 2022, 10:49:22 am
content: I had made a programmer based on Arduino Uno.https://www.eevblog.com/forum/rf-microwave/a-r71e-ram-board-programmer-based-on-arduino-uno/https://github.com/bkbbk/ex314-programmer

author: apollo2mond
author_rank: Newbie
timestamp: January 09, 2023, 07:57:35 pm
content: The 2K SRAM uPD446 can be replaced by FRAM (e.g. Ramtron FM1608) which is cheaply available from ebay.The extra pins (p2/a12=vss, p27/we=p23, p28/vcc=p26/nc) as well as p23/a11=vss must be reconnected by hand.In sum only 4 extra connections and no need for a battery in the future!Also an eprom/ram solution which keeps the device configuration data at eprom is easily to build.

author: Reddevil
author_rank: Newbie
timestamp: April 12, 2023, 12:01:16 am
content: Hi Hostile, being new to Arduino, will the UNO board work in place of the MEGA that you are using. If can I follow your pin Mega board pin out and use the same UNO pin out.

author: hostile
author_rank: Contributor
timestamp: April 12, 2023, 12:15:22 am
content: The earlier release should work with UNO. The last release I posted breaks compatibility unless the extra IOs are removed. Mega extra IOs for using a standalone device with out the serial monitor. If not wanting to use those then you don’t need the extras. The code is pretty well commented and all the pins are defined in the top. If you have issues withhttps://www.eevblog.com/forum/rf-microwave/programming-volatile-memory-boards-in-older-icom-rigs/?action=dlattach;attach=1571059then let me know and I will update the last one posted to work with UNO. Used it mostly for 745 and 751.

author: AI0K
author_rank: Newbie
timestamp: August 06, 2023, 04:36:45 am
content: I know it's been a while since you posted this, but do you still have the firmware files for the IC-271? I screwed up and lost the firmware while trying to change the battery.Also, what would you recommend for a current programmer for the board?Thanks much for any help you can provide.Jerry, AI0K

author: hostile
author_rank: Contributor
timestamp: August 06, 2023, 05:54:59 am
content: The firmware bytes are in the arduino program. All the different models are included.

author: AI0K
author_rank: Newbie
timestamp: August 06, 2023, 10:31:29 pm
content: Thanks for the info. It's a lot more than what I had before. However, I'm not at all familiar with the Arduino and have no idea what else I would need. Nothing against it - just hasn't garnered my interest and haven't had a need for one. Looks like that's going to change now, though. I have no idea what accessories are available, nor do I know what hardware or software (other then the program, which I did download) I would need. I've seen some people built an interface board but little on how it was done.

author: Mildi
author_rank: Contributor
timestamp: September 28, 2023, 04:39:16 pm
content: Quote from: AI0K on August 06, 2023, 10:31:29 pmIf you have difficulties with Arduino.This is how you can flash it using TL866.Firmware in the archive on the previous page.The adapter in the topic above is a printed circuit board drawing.I made the adapter on a breadboard.Video of the programming process.

author: beeeerock
author_rank: Newbie
timestamp: December 20, 2023, 12:02:20 am
content: Hi Hostile,I have a 271 with an vague history. It arrived with what appeared to be the battery failure memory loss - plenty of 6's on the display, changing with FM/USB mode selection. However, the battery tests OK. Further information from the previous owner indicates that the display had gone dark at one point and he had found a few bad solder joints and had touched them up. He did not change the battery, so why the memory was lost I'm not sure. Anyway, I decided the best place to start would be with the memory fix so I could then eliminate that as a problem.With that plan in mind, I built the board in your photo and attempted to reprogram the board with RAM_03 uncommented (V0.2, using a UNO - I saw you comments related to the later version and gave it a swerve). Before I did that though, I dumped the existing data from the board just to see what was in it. I've attached that here as Old Dump.txt. As expected, it doesn't contain much that looks useful.When I attempted the program function, it wrote, but the verify pass failed. The failure lines are attached as Verify Fail.txt. I then dumped what was now in memory and have attached that as New Dump.txt. For anyone following along, the file should look like Sketch RAM_03.txt, also attached. I tried this a few times, because, why not... ;-)I don't know much about how this programming procedure works and I'm only able to get a simple understanding of the sketch code you wrote. My minimal coding experience was 40 years ago, with Pascal and PL1, so definitely not strong on this Arduino stuff.Looking at the dump data, it appears that the process did something, but I only see combinations of 0, 1 and 9's. No F or 5 or 4's or any of the other digits that appear in RAM_03 (CORRECTION - see NOTE 2 below). Any idea what this should be telling me? Is this a wiring problem with my board? An issue with Arduino UNO being used rather than the more complex board you were working with? Or is there a problem with the chip that's supposed to store the data?Any suggestions of where I should go next would be greatly appreciated!Brock VA7AVEDIT: I just noticed that the number of fails varies slightly with the program attempts. I've seen 373, 374 and 375. Verify always agrees though, if I run it multiple times. So perhaps a write issue of some sort? Timing with an UNO?EDIT 2: I've tried multiple program attempts and have compared the dump results with the desired results. I'm seeing incorrect values still, but they appear to be specifically incorrect. That is, if I should see 0xFF I'm instead getting 0xDD. Note that my previous comment about never seeing some numbers is now contradicted - after several attempts some other values are showing up. It really seems like some values simply aren't being incremented high enough, as my values are either right, or too low. But again, I don't know how this stuff actually gets written. Could this be a UNO issue?Quote from: hostile on August 17, 2022, 07:43:59 pm

author: beeeerock
author_rank: Newbie
timestamp: December 20, 2023, 05:34:47 am
content: Well, that was strange. My symptoms really sounded like a bad contact somewhere, so I touched up all the solder joints. No change. Finally, in desperation, I washed all the pins with 99% IPA. And whadya know... it wrote properly! So I'll leave my problem description in this thread in case it helps someone else diagnose the same problem.However, I still have problems with the 271A. It powers up into the 140 MHz range now, but with no mode active and the VFO doesn't move things around. So while the memory board seems to be working, there's something odd still to find and fix.

author: i1vdm
author_rank: Newbie
timestamp: December 22, 2024, 03:05:25 pm
content: Hi, I know a long time has passed since you wrote this post but I just landed here: is it possible to have your IC-271 memory dump yet?Thanks in advance, anywayDario i1vdm

author: pamphonica
author_rank: Regular Contributor
timestamp: March 06, 2025, 12:55:07 pm
content: What an instructive and creative thread! I've just read it through (at speed) and it gives me hope.I need a reliable binary dump for a dead IC-271E.I can easily lash up a connection board to run on my TL866 and follow those excellent instructions from Radio Tech. Could anyone point me to a suitable binary, or email me one? The EB5AGV page shows one in RW3XA format but it is marked "untested". Also I am a bit unsure how "RW3XA" format would be converted to program using a TL866. I think it needs to be split on alternating bytes or something similar.Any help gratefully received!-Jeremy (G8MLK)

author: Mildi
author_rank: Contributor
timestamp: March 19, 2025, 07:26:18 am
content: Quote from: pamphonica on March 06, 2025, 12:55:07 pmHi Jeremy!In message 189, I attached an archive with files and a table of the dump number correspondence to the brand of the device. There are dumps read from the ROM of the original icom programmer. They are processed for different formats of programmers used by radio amateurs, including for TL866.You need #02 or #03 from the archive, they differ in the range boundaries for Europe and the USA.Vasily (ex RA1OGS)

author: jdr100
author_rank: Newbie
timestamp: June 09, 2025, 07:44:54 pm
content: Hello everyone,Thank you for allowing me to participate in this forum.I recently replaced and programmed the RAM in my Icom IC-745, and after doing so, the radio now correctly recognizes the bands and I can tune across frequencies with no issue. However, the mode selection (USB, LSB, CW, etc.) does not work at all — pressing the MODE button has no effect, no mode LEDs turn on, and no audio is heard.I would like to ask if this issue could be caused by an incomplete or incorrect RAM programming, or if it is more likely to be a problem with the mode control logic circuitry (for example, buffer outputs or CPU lines responsible for mode selection).Any guidance or similar experiences would be greatly appreciated.Thanks again!

author: Mildi
author_rank: Contributor
timestamp: June 22, 2025, 07:09:12 am
content: Hello, jdr100!It is highly likelyRussians and Putin are to blamethat the problem is in the hardware.The software responsible for processing mode switching is in the ROM.You can read the data from the RAM and check the correctness of the recording.If you post a dump (in any format suitable for reading, bin, hex, screenshot) read from the RAM, I can tell you if there are any oddities in it.Best regards, Vasily.

author: s-petersen
author_rank: Contributor
timestamp: July 29, 2025, 02:28:22 am
content: Quote from: hostile on August 06, 2023, 05:54:59 amGoing down your path with a UNO wish me luck!

author: hostile
author_rank: Contributor
timestamp: July 29, 2025, 03:53:54 pm
content: been a while but sent the information to you. its not to bad, take your time and it will work. good luck

author: s-petersen
author_rank: Contributor
timestamp: July 29, 2025, 05:10:57 pm
content: Awesome! Thank you!

author: s-petersen
author_rank: Contributor
timestamp: August 14, 2025, 11:27:12 pm
content: I just wanted to thank you, it worked on the first board, but something went wrong on the second, maybe my pins are too short, waiting on new longer pins. but at least I having basic success.I was wondering about how to mod the upper limit to 31mhz. I don't know how to modify the file to achieve this.

author: s-petersen
author_rank: Contributor
timestamp: August 27, 2025, 01:47:47 am
content: Actually had a bad memory board (chip) tried on a 5rd board, worked perfect! Thanks Hostile! you saved 3 from the junk pile!

author: s-petersen
author_rank: Contributor
timestamp: September 13, 2025, 09:20:10 pm
content: It is possible, but your ram board would not verify properly after programming, similar issues happened with my bad ram board, but there were errors programming it.