Gordak 952-v hot air solder station - high failure rate - what cause? - Page 1
Forum section: electronics / general

author: asbokid
author_rank: Regular Contributor
timestamp: July 23, 2012, 03:04:53 am
content: Hello,We have suffered several failures of theGordak 952-Vsolder station. The 952-V is one of the newer VFD models. It costs around US$150 delivered. So not the cheapest. The symptoms are dead screen and dead control buttons, cold blower and cold iron.Gordak 952-V (when working!)The seller says return the faulty stations for repair/replacement. But this is impractical. Return shipping to China costs as much as a new station.Since the problem is common - it would be better to identify and fix it, and document the solution for others.TheGordak 952-Vis driven by anAtmel ATmega8L-8PU8-bit microcontroller. The MCU is clocked externally at 8MHz. The MCU has an 8 bit AVR RISC core, 8kB of onboard flash, 512 byte EEPROM and 1kB of internal SRAM, and three digital IO ports. The VFD screen on the Gordak is driven by aPrinceton PT6312VFD controller. The PT6312 can be seen on the reverse of the board below. The MCU drives the PT6312 via a 3 wire serial interface using its GPIO lines.The Gordak's control board also has a couple ofOP07DPoperational amplifiers, and aTL431adjustable voltage regulator. Click for full-sizeClick for full-sizeSo it is not clear where the fault lies. The Gordak does have a separate power supply board. This was briefly tested and its outputs appear to be clean and in spec.There are vendors on Taobao selling pre-programmed replacement MCUs for the Gordak 952-V. This suggests that their failure is common. Yet the ATmega8 is pretty resilient, so the underlying fault with the Gordaks is probably something else.There are schematics for the earlier Gordak 952  and for the Gordak 952A  but neither are very relevant to the MCU-based Gordak 952-V. The 952-V User Manual (Chinese and English) is here for anyone who has lost it. Any suggestions or pointers would be gratefully receivedcheers,asbokidhttp://www.totobay.com/gordak-952v-intelligent-compositive-soldering-station220v_p29555.htmlhttp://www.atmel.com/images/doc2486.pdfhttp://www.princeton.com.tw/downloadprocess/downloadfile.asp?mydownload=PT6312.pdfhttp://www.ti.com/lit/ds/symlink/tl431.pdfhttp://archive.espec.ws/files/gordak.rarhttp://img339.imageshack.us/img339/2428/hotairschematicchamobil.pdfhttp://docs.google.com/folder/d/0B6wW18mYskvBQWlZN19B...

author: amspire
author_rank: Super Contributor
timestamp: July 23, 2012, 04:24:41 am
content: When you are getting a blank display and nothing seems to work at all, the first thing you do is to check the 5V on the micro, the +/- supplies on the opamp and supplies to the display chip (if you have data). If you measure the voltage across the front panel switches when they are not depresses, is there any voltage? What is the voltage on the micro Reset pin?The schematics of soldering irons are fairly simple - it is not that huge a job working out the schematic by following the traces on the PCB's. It is a few hours work, but if you post a rough a circuit, we can probably help you. Things like the display are not that important. The circuit connected to the main micro is important. The power supply circuit is also needed.

author: asbokid
author_rank: Regular Contributor
timestamp: July 23, 2012, 05:11:22 am
content: Hi Amspire,Thank you for your interestVCC and AVCC on the ATmega8L are both +5.00v and GNDs are good.VDD on the PT6312 (VFD controller) are +5.00v and good GNDsRST on the ATmega8L is +3.80v. And probing RST with a multimeter seems to cause the MCU to reset, detectable from the pump briefly pausing.V+/V- on the two OP07s op-amps both read +10.00vThe three front panel push button switches have +5.00v when not depressedSo the power supplies seem okay, and maybe the ATmega8L isn't fried after all, or at least not all of itWhat could I check now?

author: Psi
author_rank: Super Contributor
timestamp: July 23, 2012, 05:42:54 am
content: Do you have any working units? If so you could leave one on for a while, then unplug it, take the top off and check all the components for any hot spots.It might yield clues if you find something that's quite hot.And if you're willing to dismantle a working unit it makes fault finding easier.You can compare in-circuit measurements between a good and dead unit, looking for differences.

author: amspire
author_rank: Super Contributor
timestamp: July 23, 2012, 06:39:10 am
content: Quote from: asbokid on July 23, 2012, 05:11:22 amWhen it is working, does the pump run 100% of the time, or is it turned ON and Off by the micro?I would start looking at the connections to the reset pin and work out why it is 3.8V rather then 5V. It could be OK, or it could indicate it is being pulsed or is floating. If it is being pulsed, the micro can never run. Not sure why probing the reset pin should change the state of the Reset.Trace the tracks, and draw the reset circuit. I think it is worth 5 minutes.Richard.

author: David_AVD
author_rank: Super Contributor
timestamp: July 23, 2012, 06:58:59 am
content: Just going by the photos, pin 1 of the Atmel micro (RESET) seems to be floating???

author: amspire
author_rank: Super Contributor
timestamp: July 23, 2012, 07:12:35 am
content: Quote from: David_AVD on July 23, 2012, 06:58:59 amThat is interesting. They could have used the RSTDISBL bit in the micro fuses to disable the external reset pin, but if they forgot to program the fuses properly with a batch of chips, it would default to being a floating Reset pin. The fuse table is separate from the compiled micro code, so it would be easy for someone to program the micro EPROM correctly, and not the fuses.That would mean that the soldering station would run or not depending on what value pin 1 was floating at.I would add a 10K to 1M resistor from pin1 to +5V and see if that fixes the problem. The 5V supply rail track pass within about 0.2mm to pin1, but it looks like there is no connection.Richard.

author: MBY
author_rank: Regular Contributor
timestamp: July 23, 2012, 02:06:40 pm
content: That's strange! The only reason for using the RSTDSBL fuse is to use the pin for IO. But clearly the pin is not used at all, hence no need for the RSTDSBL. So, a 10-100 k to the supply and perhaps a 10-100nF to GND may be good to add.Maybe this is some sort of idiotic "protection", like sanding chips. With RSTDSBL sat, it is harder to read/write the flash from a programmer. But this is not the right way to do it. Lock bits are there for a reason.But is does not seems like this is the only problem.

author: asbokid
author_rank: Regular Contributor
timestamp: July 23, 2012, 11:50:34 pm
content: Thank you for all the advice and suggestions, guys. Much appreciatedNext plan is to scope the ATmega8 pins for signs of life. The MCU pinout is mostly understood now.The two op-amps take as input the two temperature sensors in the iron and in the hot air gun. Those analog samples are amplified and fed to a couple of ADC lines on the MCU. The MCU then uses its digital I/O lines to control the power supplies to the iron, the hotair pump and element. On the PSU board there are three triacs, just asKerry D. Wongfound with a similar solder station . Quite a simple board really, if only it worked!I still reckon the MCU is fried, or just maybe the flash or eeprom has somehow gotten corrupted. Hmm.. However, I just noticed some blackening in the very corners of the VFD screens. Not looking so good.click to enlargeclick to enlargecheers, asbokidhttp://www.kerrywong.com/2011/12/07/x-tronic-4040-hot-air-reworksoldering-station-ii/

author: amspire
author_rank: Super Contributor
timestamp: July 23, 2012, 11:55:17 pm
content: If they did forget to program the Atmega fuses, then you could read the whole code from the micro. That would be brilliant!Put a socket in, and try out your own mods.

author: David_AVD
author_rank: Super Contributor
timestamp: July 24, 2012, 12:02:17 am
content: So you're not going to try fixing the floating reset pin issue? A 10K resistor and 2 minutes work is all it will take.

author: Psi
author_rank: Super Contributor
timestamp: July 24, 2012, 12:24:12 am
content: Pretty sure the ATMEGA/TINY has a built-in 30-80k pull-up for the reset line.Although recommended, a pull-up on reset shouldn't be needed to make it run.

author: David_AVD
author_rank: Super Contributor
timestamp: July 24, 2012, 12:37:42 am
content: Quote from: Psi on July 24, 2012, 12:24:12 amFair enough. I'm a PIC person so wasn't sure.The 3.8V on the reset pin did sound odd though.

author: asbokid
author_rank: Regular Contributor
timestamp: July 24, 2012, 12:40:34 am
content: Quote from: David_AVD on July 24, 2012, 12:02:17 amI certainly will try that fix. No time left tonight though :-( You Ozzies and Kiwis are to be envied. You get to stay up all night hacking away while us Pommies are forced to bed (not least for beauty sleep which by God we need!)Viz sanding off chip markingsThis is a replacement MCU for that Gordak 952-V. I wonder which MCU it is?!cheers, a

author: asbokid
author_rank: Regular Contributor
timestamp: July 24, 2012, 01:12:28 am
content: Quote from: Psi on July 23, 2012, 05:42:54 amThanks Psi. I wish I had done that now with our last working unit before it popped as well.The "top of the range" Gordak 952V device sells for just 320 yuan (AU$50) in mainland China . But by the time the units reach Europe they cost us GB£120 and upwards (AU$180). Somebody is making a nice profitEspecially when the units only last a few hourscheers, ahttp://item.taobao.com/item.htm?id=7003704148

author: David_AVD
author_rank: Super Contributor
timestamp: July 24, 2012, 01:14:33 am
content: I think the dark patch right in the corner of the VFD is normal (assuming it's not in the viewable area). I'm sure I've seen that on brand new displays.

author: Psi
author_rank: Super Contributor
timestamp: July 24, 2012, 01:16:11 am
content: Quote from: David_AVD on July 24, 2012, 12:37:42 amYeah.You might get odd DMM measurements on reset if the watchdog or brownout detector was triggering many times a second.Need to scope it to be sure.

author: David_AVD
author_rank: Super Contributor
timestamp: July 24, 2012, 01:25:03 am
content: Even though the PSU board appears ok, I'd probably change out any electrolytic capacitors that look heat affected.

author: SeanB
author_rank: Super Contributor
timestamp: July 24, 2012, 04:59:52 am
content: The black on the VFD is normal, it is the getter used to ensure a good vacuum. If it was white the tube is farked and full of air.

author: amyk
author_rank: Super Contributor
timestamp: July 24, 2012, 06:54:12 am
content: For completeness, here is an attempt at tracing the schematic from the provided pictures.The bottom capacitor (EC4 in the schematic) is suspicious, as it is marked with the same 1uF 50V value but is less than half the volume of the one above it (EC2 in schematic). Either that or EC2 is too big for its capacityI would try to remove the MCU and read out its contents. A possibility is that PSU glitches have corrupted the memory and/or damaged it.

author: asbokid
author_rank: Regular Contributor
timestamp: July 24, 2012, 09:59:25 pm
content: Hiamyk,Oh wow! That's perfect! Much appreciatedLots of people will benefit from your workHope you enjoy doing it though!Is it worth me reading the missing cap values, and the exact socket labels? Everything will be there then.I just took your advice and ordered a serial programmer for the AVR . Just spotted a project that re-uses the PICKIT2 programmer for the AVR . There is a PICKIT2 here but as a complete novice with AVRs, it would probably all go wrongNot sure if it would help to get a parallel programmer, too, though?When those foam standoffs were pulled off the Gordak PCB, underneath were the SPI lines, already brought out from the MCU. So it can presumably be programmed in-circuit. It would be a stroke of luck if the CPU is not locked down. Maybe if the problem is explained to Gordak, they would be sympathetic and supply a hex file to reprogram it?The power board in the solder station must have a little bit of logic of its own. Those five (digital) GPIO lines you document as "J3" coming from the MCU {PB0, PB1, PD2, PD6, PD7} are labelled "DRIVER" on the Controller board, and labelled "CPU DRIVER" on the Power board. Somehow those fives lines control the pump speed and the temperatures of the gun element and the iron element. Not studied exactly how though.Thank you once again for going to all that trouble, amyk!cheers, asbokidhttp://www.ebay.co.uk/itm/140763404046http://www.sonsivri.to/forum/index.php?topic=27727.0

author: asbokid
author_rank: Regular Contributor
timestamp: July 24, 2012, 10:05:28 pm
content: Quote from: SeanB on July 24, 2012, 04:59:52 amQuote from: David_AVD on July 24, 2012, 01:14:33 amThanks guys, that's good to know. The blackening isn't visible while the screen is in situ in the case.cheers, a

author: David_AVD
author_rank: Super Contributor
timestamp: July 24, 2012, 10:48:36 pm
content: I'd still be fitting the 10K pullup resistor to the reset line.

author: amyk
author_rank: Super Contributor
timestamp: July 25, 2012, 11:04:07 am
content: Quote from: asbokid on July 24, 2012, 09:59:25 pmI've done PCB and chip-level tracing (check out visual6502.org), this board was really simple so it only took around 30 minutes. The pictures were clear enough, and I like a challenge, so why not. It also helps everyone else trying to figure out the problem as looking at a schematic is much easier than having to trace through PCB every timeCheck the caps, both capacity and ESR, they look off-brand to me and that size discrepancy is suspicious. If you do have the correct component designators (some were hidden), just post them and I can update the schematic.QuoteAt that price, a programmer is definitely worth having, but if they've programmed RSTDISBL then HVPP is the only way to unlock+erase the chip. Keeping the reset pin disconnected allows an external programmer to pull it low for programming.QuotePost some pictures of that board if you want it figured outAfter that, we'll have essentially understood the whole thing, and if you want to revive them I guess it wouldn't be too hard to write your own firmware. If the MCU is locked and dead then there's nothing to lose by trying to erase it and program your own code to e.g. flash the LEDs and display to confirm that it's still functional. That might also give some clues about the failure mode if your own code stops working on it, but I have a feeling it's related to having the heater/pump running.

author: asbokid
author_rank: Regular Contributor
timestamp: July 26, 2012, 12:41:48 am
content: Quote from: amyk on July 25, 2012, 11:04:07 amVery clever stuff! Didn't even know any of that was possible without $1m of equipment.QuoteHidden under that suspicious cap (EC4) it says "6mm". Not sure why that would relate to only one cap?Perhaps it's easiest if I annotate your magnificent PDF to include the few component markings that were hidden from view?click to enlargeQuoteAhh, that makes sense. I look forward to having a play with the serial programmer. Unfortunately, the parallel programmers are considerably outside my budgetQuoteI shall enjoy having a hack once the programmer has arrived.A guy in Estonia calledToomaso, has posted a youtube video about his Gordak 952v.  It too has failed in exactly the same way. Hopefully he soon will find this thread and your schematic!Any way, here is the power board from the 952-V. Maybe there are some clues on here to the failure?Gordak 952-v power board(click to enlarge)Gordak 952-v power board(click to enlarge)Gordak 952-v transformer(click to enlarge)Gordak 952-v VFD(click to enlarge)The component list for the Gordak 952-V power board is attached below.Quotecheers, asbokidhttp://y2u.be/wf_D_r-3o_A

author: T4P
author_rank: Super Contributor
timestamp: July 26, 2012, 07:36:12 am
content: Check the triacs

author: amyk
author_rank: Super Contributor
timestamp: July 26, 2012, 08:33:37 am
content: "6mm" is the length of the jumper wire below the cap. Go ahead and annotate it, that would be good.You don't need a full parallel programmer if all you need to do is unlock and erase chips. I've written about it before on the MCU board here. (Hint: You don't even need a PC if you've printed out the relevant pages from the datasheet!)Here's the power board schematic. Took a little longer since there were more parts.... and I have no idea what a fen nor a han is. Perhaps they meant a fan and a hen? The basic operation looks straightforward, a bunch of isolated triac controls via active-low signals, although I'm not good enough at analog electronics to decipher what they're doing with the comparator on the HV side and the optocoupler driving the pin I've decided to call SENSE.The PSU section is a half-wave for +5 and -5, and full-wave for the negative VFD drive voltage. 3VAC from the transformer is likely for the VFD filament. Besides the half-wave rectification I don't see anything else suspicious, but certainly checking the electrolytics is recommended. Half-wave produces a lot more ripple than full bridge, and non-branded caps aren't known for their longevity. Maybe they were already marginal when they left the factory.Quote from: DaveXRT on July 26, 2012, 07:36:12 amI doubt it. The display would still work, but without heat, if it was their fault.

author: asbokid
author_rank: Regular Contributor
timestamp: July 27, 2012, 12:44:55 am
content: Hi amyk!Quote from: amyk on July 26, 2012, 08:33:37 amAha! I see. They are PM'ed to you.QuoteHopefully the MCUs won't be locked. Otherwise we are a bit stuffed with no code to flash into them againQuoteAmazing work! Though you lost me at the beginning of the first paragraph! So far as I can work out, FEN = hot air gun pump motor and HAN = soldering iron.What would be a good repair plan? Maybe replace the MCU, and swap in some known good electrolytics, perhaps uprating them? On both the power board and the control board?The MCU must be borked in some way, yet everything seems in order. There are some replacement MCUs on their way. Maybe it would be good to install a DIP socket for them first. Before they arrive, the VFD output pins and those "CPU DRIVER" lines can be scoped. Though not sure what that will show. With some Chinese good luck, the replacement MCUs might not be locked, so flash/EEPROM dumps could be extracted from them for the greater goodThe integrated EEPROM on the MCU must hold the 'dynamic user configuration' since the station settings are preserved across power cycles.Those settings are for the pump motor, and for the two temperatures (gun and iron). If the EEPROM contents became corrupted during a write operation, it could in theory could cause badly-written firmware to crash. And with no EEPROM reset function, the f/w crash could be irreversible (except for re-flashing).EEPROM corruption could be caused, perhaps, by pulling the plug on the station, rather than gracefully shutting it down via the power switch on the front panel. A graceful shut-down asserts the MCU's ON/OFF line (PD4 pin). Whereas pulling the wall plug does not. Only a theory, thoughThanks once again for all your effort in working out these schematics,Amyk, and to everyone else who has offered advice, too.cheers, a

author: amyk
author_rank: Super Contributor
timestamp: July 27, 2012, 08:39:28 am
content: I've updated the schematics posted above with the new information.I wouldn't be too optimistic about the MCU being unlocked. As I mentioned before, if you erase it you can upload a simple program that just blinks the display so you can see if there are glitches/unreliability causing it to lock up.But understanding the design, it doesn't seem too hard to write your own firmware. I think it just uses PWM on the triacs, synchronised to the zero crossings of the line frequency. You can find one open-source design here:http://dangerousprototypes.com/forum/viewtopic.php?f=56&t=2457&start=15The signals on "CPU DRIVER" socket are active-low and used to switch on the heater, iron, and pump via the triacs. There's one SENSE signal which is an input to the MCU and probably used for zero-crossing detection. You can scope that one (on the isolated side, not the mains side) to confirm this.Your hypothesis about EEPROM corruption does make sense, although the EEPROM is usually most vulnerable to corruption during a write; a hard shutdown doesn't trigger a write, unless it's some bad design that continuously writes to the EEPROM every second or something like that. EEPROM endurance would also be a problem if it was doing that. (A graceful shutdown should trigger an EEPROM write. I'm not sure of the power connections so I don't know whether it's the relay that turns on a main transformer and there's a standby one, or it's used for something else.)

author: asbokid
author_rank: Regular Contributor
timestamp: July 28, 2012, 01:54:51 pm
content: Thank you once againAmykfor going to all this trouble.Using your schematics, I was up until 5am studying the board(s).Just as you expected, the "SENSE" line delivers a 50Hz square wave to the MCU. But, surprisingly, the MCU is still running, at least initially. It is continuously generating an arbitrary PWM signal on one of the "DRIVER" lines. And on power-up, it initially sends 'sane' signals on the three wire serial interface to the VFD controller (strobe, DIN and clock).This does look like a firmware problem, rather than faulty hardware.I will post some scope traces once the cable/driver has come to light.cheers, a

author: Rufus
author_rank: Super Contributor
timestamp: July 28, 2012, 05:19:46 pm
content: Quote from: asbokid on July 28, 2012, 01:54:51 pmIs there some reason you don't suspect the VFD driver chip (on which the display and buttons depend)?

author: asbokid
author_rank: Regular Contributor
timestamp: July 29, 2012, 12:48:05 am
content: Hi Rufus,Very good point. That may well be it!On the PCB, the data in and data out pins to the VFD controller are strapped together, which seems odd in itself. It also makes it difficult to see whether the IC is alive on the MCU side.The VFD controller is the PT6312, an IC made by Taiwanese chipmaker Princeton. It is a clone of an IC from NEC (the D16312) which dates back to the early 1990s. The Princeton costs just 8 cents (or less), whereas the NEC costs upwards of 90 cents in China. So it's clear why it's being used here. The Princeton is apparently "functionally compatible" with the NEC, but maybe not so resilient.The IC is in an LFQP44 but maybe the DOUT pin can be gently lifted off from its pad to see whether there is still a signal on it.cheers, a

author: David_AVD
author_rank: Super Contributor
timestamp: July 29, 2012, 01:11:50 am
content: Speaking of Princeton, I've seen issues with their versions of other makers' chips before. Mainly when they were in a high ambient temperature environment (but still within specs).

author: amyk
author_rank: Super Contributor
timestamp: July 29, 2012, 08:11:39 am
content: If DOUT is lifted it will make the MCU unable to read the state of the keys, it's open-drain so MCU probably provides internal pull-up on it and it'll see all the keys being down. I don't know what effect that would have on operation, but if it does something then that would confirm that MCU is still OK and it's the PT6312's fault.

author: asbokid
author_rank: Regular Contributor
timestamp: August 30, 2012, 04:32:53 pm
content: Hi Guys & Guyettes,Just a quick update to report success: those dead Gordak solder stations are now working fine again!It turned out the ATmega8 microcontrollers were half-fried. So they were swapped out for pre-flashed replacements ($1.50 each). The uCs were re-fitted in DIP sockets in the event they need replacing again (hopefully not though!)All the electrolytic caps on the power and control boards were replaced and uprated, including that mysteriously dainty "50v" specimen!Some header pins were also fitted to the control board for connecting a "usbasp" AVR programmer to the ATmega8.Attempts were made to connect a programmer to the microcontrollers, both the good and bad ones. Perhaps down to my incompetence but the programmer couldn't even get the device ID from the uCs. The avrdude software kept reporting a problem with SCK.The SPI lines were traced with a scope and there was clear activity on SCK and MOSI. So not sure what the problem was. Maybe that particular $2 programmer could be a duff. It is clone of Thomas Fischl's board called thebetemcu.com. Or maybe the programmer isn't compatible with avrdude. Many people seem to be reporting problems with it.Inquiries to Gordak, the maker of the solder station have so far drawn a blank. So hopefully this thread has pointers for anyone else with a dead Gordak 952-v solder station. Any way, a few photos attached below, showing two revived units.And finally a big thank you to everyone who offered advice, especiallyAmyKwho produced those excellent schematics for the 952-V (see above)cheers, aelectrolytics replaced (click for full size)replacement uC, socketed, header pins for programmer, caps not yet replaced (click for full size)Two Gordaks back from the dead (click for full size)A work of art! (click for full size)http://www.fischl.de/usbasp/

author: asbokid
author_rank: Regular Contributor
timestamp: October 01, 2012, 01:52:39 pm
content: Quote from: Keepncool (by PM)Here is oneTaobaovendor of a pre-programmedATmega8Lmicrocontroller for theGordak 952-v. See Gordakshould be supplying these F.O.C. since the fault is theirsA very reliableTaobaoagent (YMMV) has beenyoybuy.com. See . Their minimum order is US$5 though, so maybe consolidate with other items fromTaobao.Good luckcheers, ahttp://item.taobao.com/item.htm?id=9229245684http://www.yoybuy.com/en/Show/9229245684

author: casinada
author_rank: Frequent Contributor
timestamp: April 25, 2013, 02:39:03 am
content: My 952-V decided to died today, same problem, no display, dim pump sound. I contacted the seller GQElectronics (MCuMall) and I'm waiting for an answer to see if they can send me the Microcontroller or the firmware to program a new chip.Does anybody have the firmware for this unit?If all that fails I'll try to get the processor from china (never used Taobao).

author: casinada
author_rank: Frequent Contributor
timestamp: May 01, 2013, 07:23:40 am
content: I got a replacement processor for the Station. I couldn't read it with my USBAsp. It seems that it is protected. The voltages looked correct on the power supply board. Replacing the processor didn't fix the problem. Now both heating elements are enabled and the display is still dead. The controls don't work.I have to evaluate if is worth to send it for repair. This unit had very low hours (2 hours top). I'm really frustrated. I have some projects that are piling up.I guess I'll have to keep using my Weller and Ungar soldering irons/

author: amyk
author_rank: Super Contributor
timestamp: May 01, 2013, 11:13:34 am
content: Check the triacs.Since you now have an extra MCU, with the schematics above you could try writing your own firmware for it, or make a "test firmware" that exercises the other components.

author: casinada
author_rank: Frequent Contributor
timestamp: May 01, 2013, 06:08:22 pm
content: I can only program existing firmware. I downloaded the AVR stuff but haven't had the time to figure it out. Haven't programmed in years and I'm only familiar with other micro-controllers. I need to learn this one since I'm playing also with the Transistor Tester with the Atmega8, 168, 328.Thanks

author: yassinek85
author_rank: Newbie
timestamp: May 21, 2013, 01:10:42 am
content: please anyone can poste step by step how to connect and program this chip

author: amyk
author_rank: Super Contributor
timestamp: May 21, 2013, 08:18:17 am
content: You'll need the firmware and an AVR programmer... unless you want to write your own, in which case you'd be better going off and learning about that first.

author: larosa.cristian
author_rank: Newbie
timestamp: August 03, 2013, 08:13:05 am
content: Hello everyone, I would send out some good-hearted the firmware or link to purchase the chip already programmed? thanks

author: casinada
author_rank: Frequent Contributor
timestamp: August 05, 2013, 11:54:45 pm
content: The program is protected in the chip. I purchased an extra chip for $10. Still didn't solve the problem for me as it did with others. I sent the unit for repair. They didn't charged for the repair but i payed for shipping both ways and the cpu, total $50You can probably find the chip for $5 in china. Good luck

author: larosa.cristian
author_rank: Newbie
timestamp: August 06, 2013, 06:43:55 am
content: then you do not have the firmware? the chip you bought them already programmed for $ 10? give me the link? thanks

author: Psi
author_rank: Super Contributor
timestamp: August 06, 2013, 07:16:31 am
content: Now this is interesting, i had forgotten about this thread but just last week i had a ATmega8 die in a weird way that seems quite similar and it's the same chip!The chip suddenly stopped running code. Checking it i found reset was being pulled low internally when it should be pulled high by the internal pullup.Even an external 1K pullup wasn't enough to pull reset high (It got it to about 2.2V).I had to use a 220 ohm to get reset high (about 3.8V) at which point the mcu started running.Programming it over SPI works with the 220R attached but reset is only about 1V when low due to the large pullup and weak programmer sink ability.However it does all functionally correctly with the 220R pullup, even with the fault.I wonder if this is a common failure mode for the ATmega8?I noticed you had a similar reset voltage issue a few pages back.

author: larosa.cristian
author_rank: Newbie
timestamp: August 06, 2013, 07:37:06 am
content: hello, you had no checking 3v but well, I realized that I was wrong, so you think you can restore everything with a reset?

author: amyk
author_rank: Super Contributor
timestamp: August 06, 2013, 10:08:05 am
content: Quote from: Psi on August 06, 2013, 07:16:31 amThat makes sense; the RESET pin has no upper ESD protection diode since parallel programming needs to put 12V on it, and so it's entirely plausible for an ESD event to kill the lower diode and make it behave like a resistor. If I remember correctly the internal pullup is several tens of K, while from your numbers the diode has become ~1K resistance.

author: larosa.cristian
author_rank: Newbie
timestamp: August 06, 2013, 12:50:27 pm
content: I'm sorry but I am translating with a translator because I'm Italian and I do not understand English well, what do you suggest to do to prove what you say to me? you can provide an outline of the change you say so that I can try? thank you very much

author: casinada
author_rank: Frequent Contributor
timestamp: August 09, 2013, 11:58:07 pm
content: http://item.taobao.com/item.htm?id=9229245684I didn't purchase from that place but that is what I found when I was looking to repair mine.Good Luck

author: larosa.cristian
author_rank: Newbie
timestamp: August 10, 2013, 04:09:07 am
content: thank you very much but I can not buy from them because I do not understand what's written even translating the page, you know any website in English or Italian? thanks again

author: ju1ce
author_rank: Regular Contributor
timestamp: August 10, 2013, 05:45:23 am
content: Quote from: larosa.cristian on August 10, 2013, 04:09:07 amhttp://dangerousprototypes.com/2012/10/02/shopping-taobao-our-first-steps/http://dangerousprototypes.com/forum/viewtopic.php?t=5278Good luck...

author: Nykky1976
author_rank: Newbie
timestamp: June 08, 2014, 09:38:33 pm
content: you know about that?http://www.hit-electronics.com/za-vas-tehnici/uredi-instrumenti-konsumativi/razpoyavashti-stantsii-grupa/platka-procesor-za-gordak-952v.htmsomewhere in Bulgaria board without display

author: anand797
author_rank: Newbie
timestamp: January 06, 2017, 06:52:59 am
content: Hi Everyone,i have Gordak 952v and there is EEPROM problem , kindly upload EEPROM data or bin

author: anand797
author_rank: Newbie
timestamp: January 06, 2017, 10:13:53 am
content: Hi Everyone,Can somebody share hex or bin file for EEPROM