hybridfree/eevblog-posts huggingface dataset:
I repaired my Hameg HMO3522 350MHz DSO - Page 1
Forum section: electronics / repair

author: PA4TIM
author_rank: Super Contributor
timestamp: October 03, 2017, 10:47:35 am
content: My trusty scope died for the second time. A bit my fault because the former repair was temporary because the part was not on stock.So I had an idea of the problem and normally I would first test that but I tried to do it a bit methodical so people who want to learn more about repair would learn something. This was my first repair video and recording a repair is much harder then I expected. I think I must make a sort of mounting above the desk instead.https://youtu.be/-D1EXiSY3rc
GE Medical System MAC1200ST ECG service manual required - Page 1
Forum section: electronics / repair

author: ciccio
author_rank: Frequent Contributor
timestamp: October 02, 2017, 12:31:42 pm
content: I'm currently trying to repair an erratic ECG unit Model MAC1200St built by GE medical Systems.I'm searching for a service manual.Google was of no help.Anybody could indicate where to find one?Thanks in advance
Video: Debug and repair of a "dead" receiver in a Yaesu FT-1000D amateur radio - Page 1
Forum section: electronics / repair

author: w2aew
author_rank: Super Contributor
timestamp: October 03, 2017, 01:52:05 am
content: This video documents a repair I completed on a Yaesu FT-1000D that belongs to a local ham radio friend.

author: Samogon
author_rank: Frequent Contributor
timestamp: October 03, 2017, 02:32:54 am
content: Thank you. Very educational as all of your videos.
Replacing log potentiometer with a different value. - Page 1
Forum section: electronics / repair

author: kris2ff3r
author_rank: Contributor
timestamp: October 05, 2017, 08:38:14 pm
content: Hi everyone!I am replacing a volume control potentiometer in an integrated amplifier.The original one is a motorized 5kax2, log ALPS potmeter. I can't find this exact value anywhere. But I found it as a 10k.What I'm woundering about is if I could use the 10k, and wire it with a 10k resistor in parallel.Wouldn't it work just as a 5k pot then?

author: Samogon
author_rank: Frequent Contributor
timestamp: October 06, 2017, 05:53:04 am
content: In parallel it wouldn’t be linear

author: Gyro
author_rank: Super Contributor
timestamp: October 06, 2017, 09:08:46 am
content: Impossible to say without seeing the surrounding circuit.If the 10k is also audio taper then it might just drop in without messing around with external resistors. It depends on:1) Whether what is driving the pot is dependent on a 5k end-to-end resistance for some reason (a parallel 10k across the ends would fix that).2) More importantly it depends on whether whatever is being being driven by the wiper minds being driven by the higher impedance source. Adding resistors isn't going to help with that one without changing the 'law' of the pot. If the load is too low impedance then it will distort the law of the pot.

author: kris2ff3r
author_rank: Contributor
timestamp: October 06, 2017, 12:45:06 pm
content: I can't find schematics, so I don't know how it's wired.I have some photos, see attached

author: kris2ff3r
author_rank: Contributor
timestamp: October 06, 2017, 11:43:45 pm
content: All I need to know is; if I'm putting a 10k resistor in parallel with my ALPS 10k log, audiotapper NOT linear potentiometer.Will it work approx. like the ALPS 5k log, audiotapper exactly the same wattage etc. The only difference between the two is the total resistance.
HP 66332A A2 interface board repair - Page 1
Forum section: electronics / repair

author: v1t0r
author_rank: Contributor
timestamp: September 28, 2017, 03:17:56 pm
content: Recently I got a hp 66332A with 760 option in a auction advertised to work properly.Arrived well packed, in terms of appearance is as new, but when I turned on the supply I smelled something burning.I quickly found the problem, a totally burnt capacitor on A2 board.Now my question, does anyone know the value of the capacitor marked on the image?

author: Ash
author_rank: Regular Contributor
timestamp: September 28, 2017, 11:44:17 pm
content: Hi,I just popped the lid on my 66332A, it is marked "225 20K", so 2.2uF 20V, 10% is my guess. It is identical to the one directly below it in your photo.I just opened up my copy of the service manual (can be downloaded) and it doesn't document the control board, just the analogue board.. may be available in some other service manual for similar power supplies I guess..Cheers,Ash.

author: Ash
author_rank: Regular Contributor
timestamp: September 28, 2017, 11:51:18 pm
content: Here is a photo for orientation etc..Ash.

author: ElektroQuark
author_rank: Unknown
timestamp: September 29, 2017, 09:43:23 am
content: Tantalum cap, always waiting to attack!I would change all of them.

author: v1t0r
author_rank: Contributor
timestamp: September 29, 2017, 04:59:42 pm
content: Thank you Ash for all the work and quick reply.Quote from: EdoNork on September 29, 2017, 09:43:23 amMy intention is to change all.I can not trust them, tantalus cap at this age are not reliable.
Need pinout of T470 JBC - Page 1
Forum section: electronics / repair

author: fox034
author_rank: Newbie
timestamp: September 28, 2017, 05:59:12 pm
content: I bought the station hd-2b(station for T470) and I have T245. I need pinout of T470 and whether there's any resistance to identification. I would be very grateful if someone knows something.
Keithley 230 Programmable Voltage Source Eprom dump anyone? - Page 1
Forum section: electronics / repair

author: MisterDiodes
author_rank: Frequent Contributor
timestamp: September 28, 2017, 04:40:07 am
content: I've acquired a Keithley 230 Voltage Source I'd like to repair - except one of its 2732 EPROMS has lost / losing it's marbles (eprom needs to be refreshed) - I can't get a consistent data dump. The rest of the box is functional.Does anyone have an Eprom dump set for the pair of 2732's in this box? I saw a link at Xdevs but it leads to a "File not found" error, otherwise I'm not finding any sources for a bin or hex file set.My chips are labeled 230-800-B6 and 230-801-B6.

author: Jwalling
author_rank: Unknown
timestamp: September 28, 2017, 11:01:21 am
content: Here's a set I saved off. They are version B12, though.Recommend you start with a fresh set of 2732 chips, JIC.

author: MisterDiodes
author_rank: Frequent Contributor
timestamp: September 28, 2017, 01:30:58 pm
content: Beautiful - Thanks!
Easy way to test projector bulb/lamp & ballast? - Page 1
Forum section: electronics / repair

author: Bargainhunter
author_rank: Regular Contributor
timestamp: September 27, 2017, 07:36:15 pm
content: I know I can't test a projector lamp with an ohm meter but does anyone know how to narrow down the problem to the lamp or ballast. I don't want to buy another lamp and find out it was the ballast.If there is some other way, I'd appreciate your help.Thank you.

author: ggchab
author_rank: Frequent Contributor
timestamp: September 28, 2017, 09:32:45 am
content: I had a similar problem with an Epson projector. I suspect the lamp and/or the ballast are faulty. When I start the projector, I think it tries to communicate with the ballast, gets some bad information and then stops after about 20 seconds without any status (all LED indicators stay off).I read that ballasts may be some clever devices and communication protocols may be proprietary. At least, I could not find any documentation about that specific Epson one and the support did not want to make technical information public.So I am still wondering if there are some solutions to test the combination lamp/ballast
Dell 19" monitor standby  - Page 1
Forum section: electronics / repair

author: negativ3
author_rank: Regular Contributor
timestamp: September 21, 2017, 01:01:37 am
content: Hi all,Had a strange occurrance with a monitor. Left the PC rendering overnight and made sure all monitors were in standby.The Dell standby was off (power button light out), indicating no power, so I removed the power cable and re-inserted it, with the same result.When inserting the cable, I heard the "crackle" of electricity as the contacts mated.I unplugged the monitor again, and left it for 10 minutes, after which I plugged it back in and it works.Is this some kind of protection or am I seeing the start of a failure in the PSU? The PSU is internal to the monitor.Put it back into service and wait until it fails, Dave?Thank you.Andy

author: Toasty
author_rank: Regular Contributor
timestamp: September 21, 2017, 01:08:32 am
content: There are many monitors. May we have a model number? How old is the unit?T

author: negativ3
author_rank: Regular Contributor
timestamp: September 21, 2017, 01:40:27 am
content: My apologies, it's an Ultrasharp 1905FP, at least a decade old.

author: Toasty
author_rank: Regular Contributor
timestamp: September 21, 2017, 01:54:50 am
content: Thanks!Common issue as you correctly assumed, the PSU. Specifically the capacitors from that era were particularly bad. I'm amazed it lasted this long...Recap is fairly easy and inexpensive.Parts:Code:Dell 1905FP[ Max cap height 22mm ]3 - 1000@10v - 10x16 - Capxon KF - Pana FM == P12353-ND - EEU-FM1A1021 - 1000@25v - 12x16 - Capxon KF - Pana FM == P12379-ND - EEU-FM1E1021 - 2.2@50v - 5x11 - Capxon KM - Pana FC == P10313-ND - EEU-FC1H2R21 - 4.7@50v - 5x11 - Su'scon - Pana FC == P10315-ND - EEU-FC1H4R71 - 10@50v - 5x11 - Capxon KM - UCC KZE 5x7 == 565-1702-ND - EKZE500ELL100ME07D1 - 22@50v - 5x11 - Capxon KM - Pana FM == P12927-ND - EEU-FM1H2202 - 220@50v - 10x16 - Capxon KM - Pana FM == P12397-ND - EEU-FM1H2214 - 470@35v - 13x20 - Capxon KF - Pana FM @ 50v == P12400-ND - EEU-FM1H471{Sub for FM - UCC KZE == 565-1712-ND - EKZE500ELL471MK20S}1 - 150@450v - 18x45 - UCC PAG - Not Replaced; not a common failure-------15 caps - 14 replaced** Note: The FM series from Panasonic has been somewhat deprecated starting 2 years ago. Replacements are in the FR series.Also, while you're in there, redo the solder on pins of the 2 transformers for the backlights. Known to be a source of problems from poor or cracked connections.T

author: negativ3
author_rank: Regular Contributor
timestamp: September 21, 2017, 02:33:23 am
content: All I can say Toasty is thanks very much, I will get the parts on the way and look at the backlight transformers for sure.Will update again when all done.

author: Bushougoma
author_rank: Regular Contributor
timestamp: September 23, 2017, 12:50:40 pm
content: That crackle could have been arcing due to cracked solder joints on the IEC connector check those too when you open it up.

author: negativ3
author_rank: Regular Contributor
timestamp: September 28, 2017, 07:57:11 am
content: Very good point, I will give it a full health check when the bits arrive.
SMPS Mystery Controller IC - Page 1
Forum section: electronics / repair

author: lungchard
author_rank: Newbie
timestamp: September 27, 2017, 05:18:26 pm
content: I am currently trying to repair a pool chlorinator controller that has a problem with the power supply.I cannot identify the IC that is used in this unit. It is marked Q311 VJ34 but i can not find it anywhere. The Q may be a letter O or a zero, it is not clear.It is low power, switches 380VDC and has integral switching device (no external mosfet).I have attached a sketch of the circuit.If anyone can offer suggestions as to what the device may be then i would be extremely grateful.The equipment supplier refuses to help with this matter.Thanks in advance for any ideas,Richardaka lungchard but that is a long story.

author: wraper
author_rank: Unknown
timestamp: September 27, 2017, 05:32:09 pm
content: You'd better provide actual picture.

author: wraper
author_rank: Unknown
timestamp: September 27, 2017, 05:34:24 pm
content: Never mind, Fairchild FSQ311.

author: lungchard
author_rank: Newbie
timestamp: September 27, 2017, 05:45:06 pm
content: Hello Wraper,Many thanks for the reply.So fast too, the ink was barely dry on the paper!I will download the datasheet and continue with my repair.Thanks again, much appreciated.Richard.

author: xavier60
author_rank: Super Contributor
timestamp: September 27, 2017, 10:19:48 pm
content: Fairchild is now part of ON semi. Wow!

author: wraper
author_rank: Unknown
timestamp: September 28, 2017, 07:21:43 am
content: Quote from: xavier60 on September 27, 2017, 10:19:48 pmYeah, there was a bloodbath in last 2 years. A lot of semiconductor companies got bought / merged.
Nexus 7 touch doesn't work, I2C errors - Page 1
Forum section: electronics / repair

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 02, 2017, 06:08:36 am
content: This morning, I turned on my Nexus 7 to find that it no longer responds to touch. Tried a reboot with no success, also tried reseating the connectors to the touch panel and leaving the battery unplugged for a few hours. Even in recovery, the touch seems to be completely dead. Doing a dmesg shows lots of I2C errors.QuoteIs there a common issue with an easy fix or should I just use it as an altcoin miner? I have verified that the touch controller is receiving power and nothing on the board looks amiss. I mostly use it as a display for my Mooshimeter.
Metrotest MPAT30 - Page 1
Forum section: electronics / repair

author: Dataforensics
author_rank: Unknown
timestamp: September 27, 2017, 06:33:08 pm
content: Hi,I found an old dumped Metrotest MPAT30 pat tester, there is a 1992 cal sticker in it so at least that old.Seems to work apart from reading high on the 'run current' test.I have searched the Internet in vain for a service manual or even a user manual. Think the UK Metrotest was bought out by Martindale.Can anybody point me to a likely manual location.Admit I am probably out of luck with something that old.Thanks
[Solved] Sony ST-SB920 Shipping damage? - Page 1
Forum section: electronics / repair

author: spilihps
author_rank: Regular Contributor
timestamp: September 27, 2017, 05:59:44 pm
content: Hello!So i bought an nice tuner from a local auction site.It arrived with some shipping damage, some metal slightly out of "shape" on the front panel.It was cheap so i kept it. However, it does not light the display when turned on.The seller says, and also the Pictures show it turned on. But i only get a relay-click from the fm tuner part when turning it on.Also It does respond to the buttons to change A-B antenna.Im not sure if the VFD broke in the shipping or if its something more?Any ideas on were to begin on a machine like this?Please see the attached images.https://ibb.co/kBNjjQhttps://ibb.co/b6Xvr5Update:So i managed to find a badly cracked solder-joint to one of the filament traces on the display board. Everything works now!
Vintage pocket transistor - vintage trim caps - Page 1
Forum section: electronics / repair

author: sasa
author_rank: Regular Contributor
timestamp: September 27, 2017, 06:26:55 am
content: I have a vintage AM pocket transistor from '60s. It have some sentimental value more than I prefer to repair it, however I would try...The first problem I notice is one broken old style trim cap ("the white one" as shown on picture). However, I failing even to find datasheet for these old trim caps. I doubt they are still in production, however, without schematic it is hard to replace it with nowadays. I have no better idea except to try to buy any other similar vintage pocket transistor and salvage it.Anyone is aware these are in production in small quantities at least?Even datasheet pointer can be helpful.

author: Toasty
author_rank: Regular Contributor
timestamp: September 27, 2017, 06:46:05 am
content: It's not a cap, rather an IF (intermediate frequency) transformer. Most likely a tuned style. Essentially a threaded ferrite core over 2 coils and a capacitor.There should be some markings on it that can help determine the values.Google: miniature IF transformersAlso, check out some vintage/antique radio sites. There's still a ton of these out thereT

author: sasa
author_rank: Regular Contributor
timestamp: September 27, 2017, 07:14:07 am
content: Thank you very much for clearing all!
LGP32-11P forced power on - Page 1
Forum section: electronics / repair

author: ionicwake
author_rank: Newbie
timestamp: September 27, 2017, 02:22:46 am
content: im trying to use LGP32-11P for powering a few led lights, a pi, and a small 12 volt audio amp. for the life of me i cant get this supply to turn on. ive tried tieing the inverter on and power on pins to ground individually and together. no joy. this typically works, and the supply worked before i pulled it from a broken tv.any assistance would be very appreciated.http://i653.photobucket.com/albums/uu252/ionicwake/20170926_201017_1.jpghttp://i653.photobucket.com/albums/uu252/ionicwake/20170926_200956.jpghttp://i653.photobucket.com/albums/uu252/ionicwake/20170926_200948_1.jpg

author: Toasty
author_rank: Regular Contributor
timestamp: September 27, 2017, 02:53:59 am
content: Photobucket: Please update your account to enable 3rd party hosting.3rd Party Hosting Usage: 100%

author: ionicwake
author_rank: Newbie
timestamp: September 27, 2017, 03:02:19 am
content: https://imgur.com/a/B2fWythat work?

author: Toasty
author_rank: Regular Contributor
timestamp: September 27, 2017, 03:11:41 am
content: From cold side ground, (north of the dotted line) find a standby voltage on one of the 2 connectors, P201 or P203. May be 5V-12V, but will always be present when just plugged in. Connect that through a 150? resistor to Power On.BUT, it may not stay on since CCFLs for the backlight are not connected...YMMVT

author: ionicwake
author_rank: Newbie
timestamp: September 27, 2017, 03:20:55 am
content: im not getting standby voltages from anything on this board. which seeing as it was just working is disappointing.

author: ionicwake
author_rank: Newbie
timestamp: September 27, 2017, 04:00:53 am
content: aha! got it. it must have been dropped. the fuse was bad.

author: Toasty
author_rank: Regular Contributor
timestamp: September 27, 2017, 04:06:58 am
content: Good!Was going to suggest you hook it back up to the TV, but your picture shows we're a bit beyond that point...T

author: ionicwake
author_rank: Newbie
timestamp: September 27, 2017, 04:27:10 am
content: the screen and many parts of that tv were kicked in. somebody moved and didn't want to take it with them so they kicked it. i see them all of the time around my apartmentWhat a waste
What component is this? - Page 1
Forum section: electronics / repair

author: brauliochi
author_rank: Newbie
timestamp: September 26, 2017, 11:14:52 pm
content: Hi, best regards, I trying to know which component is this (image attached), this pcb is a control for acoustic module of a coin changer CF7000, this module sens the level of coins in tubes for changer, and is very commun that broke, and put a new one complete module

author: ataradov
author_rank: Super Contributor
timestamp: September 27, 2017, 01:59:49 am
content: You need to either take pictures that are well lit and in focus, or remove labels from them and see what markings they might have.
Help identifying Mosfet on Xantrex 500, 12 to 220Vac Inverter - Page 1
Forum section: electronics / repair

author: carbono.silicio
author_rank: Contributor
timestamp: September 23, 2017, 02:09:15 pm
content: Hello All,Bought a Xantrex 500, 12Vdc do 220Vac Inverter on a local flea market but it doesn't work. Took out 4 Mosfet's of one side and with the diode test between drain and source after touching momentarily on the gate, all of them show 0,017V and the DMM beep's continuously, instead of the normal 0.7V diode forward voltage.I presume these Mosfet's are bad but the ID markings are erased as pictures below show.Does anyone have a clue of witch ones might be? or similar one's?Thank you very much.

author: technogeeky
author_rank: Frequent Contributor
timestamp: September 23, 2017, 07:23:11 pm
content: I foundthis linkfor decoding "3rd generation" mosfets from IR.My best guess given the picture was IRF247 or IRFZ47 (IRFZ makes sense given manufacturer and package, and IRFZ4 is allowed but evidently IRFZ47 is not).Good luck!

author: macboy
author_rank: Super Contributor
timestamp: September 26, 2017, 04:21:43 pm
content: Quote from: carbono.silicio on September 23, 2017, 02:09:15 pmThat is expected. You should not get a diode drop across drain-source of a MOSFET that is turned on. There isnota PN junction between drain and source, as there is in a BJT between collector and emitter. A fully-on MOSFET should have a low resistance between D and S (See RDSon).
generator CHAUVIN ARNOUX CA910 - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: September 26, 2017, 11:03:20 am
content: Hello everyone! I am looking for the secondary voltages delivered by the transformer of my gbf CHAUVIN ARNOUX CA910, because the latter is short circuit free on the primary and therefore blown up the fuse. The transformer has 3 windings: the first one has a midpoint (therefore double), the next one has a single winding. Can anyone do a voltage reading on a running gbf ?? Or, could someone be the schema ?? Here, in France, it is the brand CHAUVIN ARNOUX, but maybe there is an equivalent like GW INSTECH. Thank you for your help (photo attached)
Tektronix 2430A timing/gain problem under 100us both channels - Page 1
Forum section: electronics / repair

author: lordvader88
author_rank: Frequent Contributor
timestamp: September 25, 2017, 10:10:14 pm
content: I replaced a CCD hybrid chip and fixed the main CH1 gain problem.Now I still have some triggering problems, its jitters and is hard to lock in.And a big problem, I go under 100us, the vertical gain on both channels goes way off, way over magnified and a wall of blur. I can make out blurry traces of test signals on both channels, its its a mess and it won't center or do anything right position-wise. Acts the same for AD/DC coupling, and both traces still match horizontally and I can move them side/side. And so the triggering is still same it seems to me.And its not just showing a zero line either, regardless of the V/div. Although I made a couple of crystal oscl' circuits and I could get the signal zoomed in a 50ns or so, and somewhere under 20mV/div I think, and it still on both traces, but how much was the real signal strength IDK. But the frequencies where 6,8, 12, MHz, maybe 24MHz too. Time to fool around more.Changing the bandwidth from full 200MHz back to 50 and even better 20MHz , improves the blurry mess a bit. And does turning 'smooth' on. But sometimes its better 'smooth off' To pick out whats there.I still have 7000,8000,9000 problem codes (however its not calibrated either and in videos people say that fails some tests too), I need to cross of the list the ones fixed with this new CCD IC.Right now I have a 134KHz on both channels at. I can make out to ghost sine waves , ch2 is doing better, make easier to make it out, its filling in the the whole area of the wave light green. Ch1 is more like making vertical lines to the differents heights along the waveform.The vertical gain only barely works at zero, the signal more or less dissapairs above/below zero vertical. It is getting the P2P voltage tho at 5us.

author: lordvader88
author_rank: Frequent Contributor
timestamp: September 26, 2017, 01:35:52 am
content: I swapped the 2 Pre-amp chips again, # 2 is in 1, and must have had a bad connection before, because now ch1 seem to work fully at all s/div and all that crazy noise is gone this time from ch2, and ch1 works. The triggers are still funny.And Now Ch2 still looks like a funny ghost image filly in the test wave.Under screen intensity control, when switching vector graphics off, I get a nice but fairly dotted sine wave trace, but also some bright central trace, and does strange stuff when scrolling up/down
Easiest way to flash Winbond 25Q32/ 25Q64? - Page 1
Forum section: electronics / repair

author: sasa
author_rank: Regular Contributor
timestamp: September 27, 2017, 01:01:04 pm
content: What would be easiest way to flash Winbond 25Q32 or 25Q64 (both SOIC 8-pin)? I would need at least to flash 4MB firmware to replace in my old LED TV (freeze and finally no picture after 5 years of correct work) no body have boards anymore. Not to mention board would be extremely expensive and used, if I even manage to found it, thus I would try myself this much cheaper way.Anyone have experience with?What I have is several arduinos (328p and 2560), PICkit2 and PonyProg, all clones, which can flash small 25xx memory through SPI, however never flash memory chips more than 256Kb with any of these and I'm not certain it is possible at all, at least until I receive these memory ICs.Thanks in advance.

author: Rasz
author_rank: Super Contributor
timestamp: September 27, 2017, 06:43:19 pm
content: https://forum.arduino.cc/index.php?topic=324009.0but I doubt its the TV firmware that went bad, most likely supply or backlight

author: sasa
author_rank: Regular Contributor
timestamp: September 27, 2017, 07:49:39 pm
content: Thank you.I have found that lib, flashrom + frser-duino. even flashrom + PICkit2. But all that I never tried. Thank you again for suggestion.Hence, I have made years ago 3.3V power supply for arduino (328p) clone. It would be extremely slow through UART, however at least do not require special programmer.I have already change all caps on power supply board with branded ultra low ESR, as well on MB and confirmed back light works correctly, however problem persisted. After calling official service, they recommend changing the memory chip with latest firmware.I suppose TV use some specific blocks to save current configuration and various settings with probably including CRC and load/check during turning ON / Wake up. Datasheet for 25Q32 state 100 000 E/W cycles, which is about 55 E/W cycles per day and then seems quite possible to fail after 5 years, if save status periodically or on standby...In any event, if changing the chip also fail, TV will probably finish in recycling center.
CMU200 HDD empty - new Install - Page 1
Forum section: electronics / repair

author: DF8SEM
author_rank: Newbie
timestamp: September 17, 2017, 08:57:53 pm
content: Hello,my HDD from the R&S CMU is fully empty.How can I restore this? I have now installed Windows 98. What drivers and software do I need for the basic functions? Is this only possible with a copy of another CMU? Need help rebuilding the hard disk.I only need the spectrum analyzer and signal generator for private amateur radio tests.What software and drivers do I need?I would be very grateful for any information.de df8sem

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: September 20, 2017, 09:35:51 pm
content: Hi,Not sure what you have as a HDD in the CMU200, but our Fleet of CMD60s use an IBM Travelstar 5GB drive with a DOS 5.0 OS. So if yours is using Windows it's new by comparison. We have been cloning drives in these to try to keep these operational. Not all drives work in all units. It may depend on Options installed etc. We are still learning.

author: tmbinc
author_rank: Frequent Contributor
timestamp: September 21, 2017, 09:51:51 am
content: The pickyness of the HDD option depends on the version of the frontpanel. I successfully replaced the HDD with an SSD on a CRTU (which really only makes sense if you're going to use the CRTU windows functionality; not related to CMU200).For the CMU, the software is DOS-based. You could start by taking a look at the most recent firmware, but I think the software version manager etc. will be missing. Best bet is to clone an existing drive.

author: CJay
author_rank: Super Contributor
timestamp: September 21, 2017, 12:34:53 pm
content: I have a drive with a base install on it which I bought from eBay, it's a genuine R&S spare, you can add the various options by downloading them from R&S.If you're interested I can sell it to you for what it cost me?

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: September 21, 2017, 06:03:47 pm
content: Yes, we've successfully cloned to SSD's as well. Also discovered that some Options are embedded in the HDD. Cloning, then booting on another CMD60 enables the Option.

author: _Wim_
author_rank: Super Contributor
timestamp: September 22, 2017, 08:07:35 pm
content: Quote from: DF8SEM on September 17, 2017, 08:57:53 pmHi, I have made a image of the HD in my CMU200 as a precaution. I can send it to you (best contact via PM). The image was made using the HD RAw copy software (http://hddguru.com/software/HDD-Raw-Copy-Tool/).

author: DF8SEM
author_rank: Newbie
timestamp: September 24, 2017, 09:55:22 pm
content: Hello @ all,thanks for all answers. I have get an Copy of the HDD from the Seller. Now the CPU is running.T H A N K S
Failed microswitch - Page 1
Forum section: electronics / repair

author: hamster_nz
author_rank: Super Contributor
timestamp: September 20, 2017, 09:09:38 pm
content: I've repaired a Voice recorder switch (something likehttps://www.fishpond.co.nz/Health/AbleNet-10002100-Bigmack-Communicator/0736846869142The fault was a standard microswtich - rated 1/2A 125VDC, 1/4A 250V.The fault was that the device would play back, but it wouldn't record. The cause was that the NO contact would not stay closed while the switch was depressed. The switch is grounding a pull-up resistor on the microcontroller, so only a few mA is being switched.Another complicating issue as that the return spring on the switch was being used as the 'lifter' for the external switch plate - when I replaced the switch I had to include some open-cell foam to give my weaker microswitch some added oomph.My questions:- Does using a mains-rated switch to switch minuscule currents and voltages case it to fail early (ie. do they need the higher voltages to keep the contacts clean?)- If a microswitch is not the correct thing to use, what is the correct thing to use?- Should there be mechanical isolation from the switch pad to the switch - so if somebody bashes the switch the full force is not directly transferred to the switch?- is using the switch as a spring 'bad form'?- Where can I get some microswitches with greater lifting power?edit: fix typos

author: hamster_nz
author_rank: Super Contributor
timestamp: September 23, 2017, 08:17:36 pm
content: So I had a look to see what was wrong...It looks like there is something like an oxide or something building up on not the switch contacts but the pivot point (on the left in pictures). It also built up the unused NC contact. Doesn't seem to be moisture or contamination.Maybe it is some sort of corrosion from the DC potential over it? - I can't help feeling that if the wires were swapped over if would only upset the NO contact, where it would be harmless...

author: Gyro
author_rank: Super Contributor
timestamp: September 24, 2017, 09:26:09 am
content: Mains rated microswitches will use a contact material suited to mains switching without excessive arcing, probably one of the silver alloys, eg. Silver Cadmium oxide, which is not good for signal switching.If you're lucky, you may be able to find an alternative switch with gold flashed contacts. Check for minimum current/voltage spec.You could try adding a capacitor directly across the switch contacts. That would give a current pulse through the contacts as they close whichmightbe sufficient to allow them to self-clean.

author: SeanB
author_rank: Super Contributor
timestamp: September 24, 2017, 09:56:56 am
content: Replacement should be a V3 style microswitch with gold plated contacts, not a 10A one. This is designed for low level switching reliably.
Help me find a SMD Device with 82C marking - Page 1
Forum section: electronics / repair

author: CrazyTiger
author_rank: Regular Contributor
timestamp: September 24, 2017, 07:56:36 am
content: Hi,I am trying to repair a super old Ericsson Radio Relay Transceiver.https://www.esato.com/board/ui/68iHIG9uUumUoYNNa0CG.jpgThe receiver side is having a very bad sensitivity. After taking apart the 43kg beastI found on the receiver module the input rf goes to multiple stages of amplification before going into the mixer. Good news is one of the amplifier isshorted bad news is I am not sure whats the exact replacement is.Its a SOT-363/SC-70 6 Pin Package with a marking of 82C. The receiver works from 600MHz to 980MHzAt the moment i am waiting for parts to make an extension jig so I can probe the bias voltage of similar amplifiers in the board to have an idea what operating voltage it should be.My initial guess is its a MGA-82563, it fits the smd code, the package and the frequency range. the pin assignment even the gain seems logical but is there any other option,please feel free to suggestThank You
Mosfet 87350D with defect - Page 1
Forum section: electronics / repair

author: jcsouza
author_rank: Newbie
timestamp: September 16, 2017, 01:49:44 pm
content: My notebook have stopped working and i did try to fix it my self, problem is that a can't find the part to buy and complete the repair. The part in question is a Mosfet 87350D TI 663 ZJC7 E3. Did any of you know this little nasty guy? I want to know where to buy and if its not possible: there is any other piece similar that can replace it?

author: Toasty
author_rank: Regular Contributor
timestamp: September 16, 2017, 01:55:12 pm
content: Hello,eBay:http://www.ebay.com/itm/181692873105T

author: jcsouza
author_rank: Newbie
timestamp: September 16, 2017, 04:00:48 pm
content: This one you posted whats the diference between he and the one i posted?

author: Old Don
author_rank: Regular Contributor
timestamp: September 23, 2017, 02:26:52 am
content: http://www.ti.com/product/CSD87350Q5D
HP 2801a Quartz Thermometer Manual/Schematic needed - Page 1
Forum section: electronics / repair

author: Lamima
author_rank: Newbie
timestamp: September 22, 2017, 10:12:04 am
content: Hello,i got a very old (some q-control stamps are showing April 1964) quartz thermometer but without any papers belonging to it.Unfortunately the needed probes are also missing...I planned to make a "replacement" probe but i will need a schematic of the thermometer itself to understand how the input signals should look like.Does someone have the manual/schematic?RegardsMarco

author: Tomorokoshi
author_rank: Super Contributor
timestamp: September 22, 2017, 03:45:33 pm
content: Artek has it:http://artekmanuals.com/manuals/hp-manuals/Search for "2801".
Marantz SR 800 schematic / servicemanual - Page 1
Forum section: electronics / repair

author: 4cx10000
author_rank: Regular Contributor
timestamp: September 19, 2017, 01:37:21 pm
content: Hi!Have searched google for this Marantz SR 800, but to no avail. Anyone out there know where to find one? This receiver is no rocket science, but I really like to have at least a schematic to look atI just took off the cover...Thanks in advance

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: September 21, 2017, 08:26:49 pm
content: You might try hunting on SR810 as well, since it appears nearly identical...http://www.kupujemprodajem.com/big-photo-50871889-1.htm

author: 4cx10000
author_rank: Regular Contributor
timestamp: September 22, 2017, 08:49:44 am
content: Thanks SoundTech-LG!Well, the SR 810 was also an impossible mission. Anyhow, I have fixed the receiver, it was an internal short in the hybrid amplifier STK459. Luckily I had one in a drawer that I bought for 20 years agoAnyway, thanks for your help!
Tek 2215, strange behavior on CH1 - Page 1
Forum section: electronics / repair

author: DigitalAura
author_rank: Contributor
timestamp: September 20, 2017, 10:01:45 pm
content: Hey Guys, new to the forum and I was hoping somebody had an idea what could be wrong with my new scope I just got off of ebay.Sine wave kinda looks okay apart from what looks like square wave artifacts... It gets real interesting when I try to view a square wave.It would be awesome if somebody knew what was going on here and what I would need to do to fix this, it only happens on channel 1, channel 2 is perfectly fine.Thanks

author: David Hess
author_rank: Super Contributor
timestamp: September 20, 2017, 10:59:04 pm
content: You do not give the horizontal and vertical settings but it looks like there is an open in the high impedance circuits before the buffer of channel 1.

author: cdev
author_rank: Super Contributor
timestamp: September 21, 2017, 01:57:05 am
content: This might be the problem, the little red circle shows the switch for coupling is set to "AC" - It should be set on "DC" to view a square wave.

author: DigitalAura
author_rank: Contributor
timestamp: September 21, 2017, 12:22:28 pm
content: Nothing to do with settings but thanks anyway. I'll dig out the service manual and check the first solution though for sure.
Which oscilloscope would you tackle first? - Page 1
Forum section: electronics / repair

author: MaxwellFaraday
author_rank: Contributor
timestamp: September 20, 2017, 09:22:53 pm
content: About a year ago I "won" an auction that included a s-ton of lab equipment. My ridiculously low bid $148 yielded an absurd amount of equipment in various states of operation. I've enjoyed opening the cases of the simpler devices and exploring.Five oscilloscopes were included in the auction. All power on, but have issues -- typically tube/display related. I'd like to select one of these scopes and see if I can develop a deeper understanding of its design and operation. I have no ambition to get any of these scopes operational, but that'd be nice. More of an autopsy than a resuscitation. I typically have lots of projects like this going at once as I find inspiration and ah-hah moments at odd times.I'd love to identify the best scope to start exploring. A simple scope with a thoughtful design and some documentation seems obvious. Can anyone offer a suggestion? The 7104 and 7834 seem to be too complicated, although I love opening the cases of those and looking at the circuit poetry.Here is what I have:Tek 475A (with DM44)Tek 2445BTek 7104Tek 7834Hameg HM208Thanks.--k

author: Ian.M
author_rank: Super Contributor
timestamp: September 20, 2017, 09:52:30 pm
content: IMHO, the Tek 2445B is probably the best candidate. The Tek 475A has the added complexity of the built-in DMM, and the Hameg HM208 is a hybrid analog/digital scope. OTOH Dave did a video (EEVblog #502) on the rather similar HM205.Do try to get the 2445 fully operational - its a very well specified traditional CRO that would be an asset in any workshop that doesn't have a tens of Kilodollars test equipment budget.YMMV.

author: The Guy
author_rank: Regular Contributor
timestamp: September 20, 2017, 09:59:17 pm
content: Don´t stress.... I´ll take them all

author: David Hess
author_rank: Super Contributor
timestamp: September 20, 2017, 11:00:47 pm
content: The 475A is the easiest to maintain of those so I would start there. Except for the delta delayed sweep function, the DM44 is mostly separate from the oscilloscope itself.

author: texaspyro
author_rank: Super Contributor
timestamp: September 20, 2017, 11:22:08 pm
content: I'd say 90% of Tek scope problems are due to bad power supply/distribution capacitors... particularly shorted dipped tantalum capacitors. Next would be out-of-spec electrolytics in the power supply.Shorted tantulum caps are usually easy to spot since they are usually burned to a charred crisp and stink to high heaven... the newer the failure, the greater the stink.

author: MaxwellFaraday
author_rank: Contributor
timestamp: September 21, 2017, 07:19:52 pm
content: If you are in the SF Bay Area and interested in working with me on any of these, I'd be happy to give you one.

author: MaxwellFaraday
author_rank: Contributor
timestamp: September 22, 2017, 07:18:05 pm
content: There is also a Tek 2465 in the pile, if that makes any difference. --k
Help Identifying SMD Parts - Page 1
Forum section: electronics / repair

author: marc.hickling
author_rank: Contributor
timestamp: September 20, 2017, 05:38:49 pm
content: Hey I have two smd components on a small pcb that I'm trying to identify - can anyone help?Part markings are:50L02with a circular logo (does anyone know of this logo)andM36PAboth seem to be in the leadless package type and I believe them to be DFN, but thats a guess...thanks!
Help identify Fairchild mosfet - Page 1
Forum section: electronics / repair

author: Samogon
author_rank: Frequent Contributor
timestamp: September 19, 2017, 06:30:09 am
content: It is part of megger mit310 i think it is power mosfet. Cant find datasheet for it.F DG31AB

author: texaspyro
author_rank: Super Contributor
timestamp: September 19, 2017, 02:55:33 pm
content: Quote from: blueskull on September 19, 2017, 06:41:14 amWanna bet? 365 days / year divided by 7 days per week -> 52.14 weeks per year (52.28 for leap years). That .14 is week 53.I had some Sylvania LED light bulbs that were recalled. The CPSC recall bulletin listed affected date codes. I had some bulbs with a 53xx date code and were not listed in the CPSC recall bulletin. I sent them an email and within two days they updated it to include the week 53 bulbs. Amazing response time from a government agency.
Plasma picture and audio goes bad - Page 1
Forum section: electronics / repair

author: Rolomoto
author_rank: Newbie
timestamp: September 14, 2017, 05:33:49 pm
content: Toshiba 42hpx95 that loses both video and audio. Audio doesn't go out that much. I think it might be heat related as the problem starts after the TV has been running for say 15 mins.

author: bjcuizon
author_rank: Frequent Contributor
timestamp: September 17, 2017, 06:51:40 am
content: If you think it is heat then go check the caps, it might be well bulged.And then if not, thou shall check voltages.Bad Power supplies on TV's will cause funky stuff like video loss and crappy/no audio.Hope that helps.
Need help repairing my monitor - Page 1
Forum section: electronics / repair

author: MassDestruction
author_rank: Contributor
timestamp: July 10, 2017, 11:26:41 am
content: Hi EveryoneI'm currently trying to repair my computer monitor. The problem I'm encountering is that the hdmi port randomly goes out. I opened it up and it seems like a Zener Diode blew up. I have an image of the crusty diode below. Looks like it burned a tiny bit of the board as well. I also visually checked the caps and they look fine. So the question I have is how do I figure out what Zener Diode to replace it with? I've tried searching for a schematic with no luck. Also as a result of the Zener Diode blowing up is there anything else I should be looking for in terms of damage? The brand and model # of the monitor is the Asus VH236H. The board # is 715G3221-2Crusty Zener DiodeFull shot of the pcb.Board Model number

author: madires
author_rank: Super Contributor
timestamp: July 10, 2017, 12:02:36 pm
content: Manufacturer and model would be helpfull. And if you don't wan't to pay for photobucket please look for another image hoster or upload your images directly.

author: kripton2035
author_rank: Super Contributor
timestamp: July 10, 2017, 12:15:14 pm
content: "visually checking the caps" isn't checking the caps...get yourself an esr meter it will help you in almost all your repairs.or build one from the links below.

author: MassDestruction
author_rank: Contributor
timestamp: July 10, 2017, 12:45:40 pm
content: Quote from: madires on July 10, 2017, 12:02:36 pmWow thanks for pointing out what photobucket was doing. So annoyed right now. I updated the opening post with the Brand, model, and board number as per your suggestion. The images have been updated too. Thanks for pointing that out.

author: MassDestruction
author_rank: Contributor
timestamp: July 12, 2017, 06:01:31 am
content: So I managed to find what the Zener Diode is. It is a RLZ 5.6B LLDS. I managed to find the service manual on the net with full board schematics. For anyone interested in this monitor they can find the schematic herehttps://elektrotanya.com/asus_vh232h.pdf/download.html

author: EPTech
author_rank: Regular Contributor
timestamp: July 14, 2017, 12:25:33 pm
content: Also, be sure to check the resistor, if any, that is in series with the zener. If a zener fails, the resistor will follow in many cases.

author: chhrisedwards
author_rank: Contributor
timestamp: September 18, 2017, 01:52:02 pm
content: To repair the computer monitor, First do the visual inspection of PCB with the help of technical tools and then replace the damaged part if found. Now, check all the components working properly or not.

author: perieanuo
author_rank: Frequent Contributor
timestamp: September 18, 2017, 03:49:33 pm
content: It's soldering problem between connector up to main processor or power module issue, bad caps or bad soldering. Check first one, if you have a scope check processor voltage stability. Regards, pierreEnvoyé de mon HUAWEI NXT-L29 en utilisant Tapatalk
[Phone Screen Repair] Correctly applying adhesive strips - Page 1
Forum section: electronics / repair

author: faekjarz
author_rank: Regular Contributor
timestamp: September 16, 2017, 03:43:42 pm
content: Hey there, Engineerds and otherwise Professionals!I recently replaced the broken (shattered) display of my Cubot P11 smart phone.It works fine now, but i applied the adhesive strips with method A (see attachment). Now my screen is not level with the bezel. I think this is caused by my flawed application of those adhesive (double sided sticky) strips. I think this method caused the display / screen assembly to squish some of the adhesive strip down to the horizontal plane, and effectively creating a stand-off, raising the display assembly above the bezel.1) What do think of method B?2) Do you think application method B would keep the replacement display level with the bezel? I think i figured it out, i can't embed uploaded attachments (photos) into posts …as i could with -tags and external sources …i'll have to cope with this inconvenience for now, i guess. …well, at least not without finally posting / publishing the post first, and then copying the attachment URL into an -tag …as i did in this post