hybridfree/eevblog-posts huggingface dataset:
Glue for sticking down loose PCB tracks and pads. - Page 1
Forum section: electronics / repair

author: philpem
author_rank: Frequent Contributor
timestamp: July 26, 2019, 09:41:11 am
content: I'm trying to follow the IPC7711/21B process for re-attaching some QFP lands. I've been using Araldite Rapid (a 5-minute epoxy).While this holds the pads great while it's setting, it lets go of the lands as soon as it sets. It's great for holding greenwire patches in place, though.Does anyone have a favourite, reliable glue for re-sticking loose PCB pads and tracks?Cheers,Phil

author: marshkillz
author_rank: Newbie
timestamp: July 26, 2019, 04:11:05 pm
content: At work we use hysol for gluing lifted pads.

author: philpem
author_rank: Frequent Contributor
timestamp: August 02, 2019, 10:03:42 am
content: The grey stuff that's sold for aviation and hi-rel applications?Cheers, I'll see if I can get my hands on a tube though I recall it's quite expensive.In the meantime I pitched the Araldite and bought a new tube of it. Looks like my old tube had suffered some kind of degradation because the new stuff works far better!I didn't see a sell-by date or shelf-life on the tube, but the new stuff is labelled "use within a year" so I'll stick to that this time around.
GM MDI2 (Hardware is same as BOSCH MTS6531) repair - Page 1
Forum section: electronics / repair

author: Kaluluka
author_rank: Contributor
timestamp: June 09, 2021, 06:24:06 am
content: Hi!I have two Partially working GM MDI2 (BOSCH MTS6531 hardware) on bench.Does anyne comme across these and maybe have some repair information?I'm awaiting fo microscope to arrive, to do the repair.On both units, there are some critical voltages missing: whats misssíng on one unit, is available on other one and vice-versa.Regards,
Goalzero Sherpa 50 Repair - Page 1
Forum section: electronics / repair

author: LarryP78
author_rank: Newbie
timestamp: May 17, 2022, 08:38:13 pm
content: Does anyone know who makes the part labeled as U2 in the photo and what it does? I've been unable to deduce the OEM and device type from the part marking.

author: fzabkar
author_rank: Super Contributor
timestamp: May 17, 2022, 08:43:44 pm
content: That's Microchip's logo.Could it be a custom programmed PIC microcontroller? Can you discern any YWW/YYWW (Year/Week) date codes from the other ICs? That would help to exclude the date codes from the part markings (eg week 19 of 2013, week 14 of 2014).

author: LarryP78
author_rank: Newbie
timestamp: May 17, 2022, 09:20:02 pm
content: Thanks for the quick reply. I also thought it was Microchip. While the logo is similar it doesn't match Microchip's logo. The angles within the IC logo are different compared to Microchip plus the IC marking doesn't have any sharp corners like Microchip's logo. I've attached a photo of a Microchip part. The only product Microchip shows on their website with 1414 in its part number is EMC1414 which is a 10 pin device.

author: fzabkar
author_rank: Super Contributor
timestamp: May 17, 2022, 09:38:22 pm
content: Can you provide a full photo of the PCB so that we can see the component in context?Can you identify the ground and Vcc pins?

author: LarryP78
author_rank: Newbie
timestamp: May 18, 2022, 12:35:09 am
content: Thanks for helping me pursue this matter. U2 pins 1 and 3 measured 9.9VDC with 10.2VDC applied to the wires that lead from the battery pack. An LM35L is nearby U2 and it measured 10.2 on pin 8. U2 pins 10, 11, and 15 are at ground potential. Attached is a photo of the board.
Goerz Electro Universal Counter FE 3101 - can't find any info about it! - Page 1
Forum section: electronics / repair

author: fredswed
author_rank: Newbie
timestamp: August 16, 2025, 07:43:21 pm
content: I recently got a delightful little frequency counter made by Goerz Electro from a flea market. The model is named "Universalzähler FE 3101" which translates to "Universal Counter FE 3101". It was probably built in 1969 or 1970 based on component date codes. Since it is a small and useful vintage counter with nixie tubes made by a well-known German company I expected it would be trivial to find tons of information about it.Turns out I cannot find a single document, video or web page that mentions it!The Simpson 2726 looks like a very similar instrument. However, the insides looks different so I don't think it's a rebranding or direct copy.The Simpson 7026 is also a close look-alike but uses Panaplex displays and has some additional functionality.While documention like a schematic would be great, I don't really need it at this point as my instrument works.But it would super interesting if anybody can shed any light on the history of Goerz counters and why they seem to be so few and far inbetween.

author: factory
author_rank: Super Contributor
timestamp: August 16, 2025, 08:08:17 pm
content: Every part inside that looks US made, except for the mains power inlet.You were very close to finding the manual, it's a Simpson 2725;https://archive.org/details/manualsplus_02338/mode/2upDavid
Going mad in repairing Metex MS-9150 Ohmeter  - Page 1
Forum section: electronics / repair

author: Fred_TV
author_rank: Newbie
timestamp: April 30, 2023, 04:30:34 pm
content: HiI own an old Metex MS-9150 instrument with a strange behavior in its DMM ohmeter:The displayed resistance is exactly HALF the value of resistor under test in all the (automatic) resistance ranges !DMM is based on MAX134 together with Metex KS57C2016 custom uPI got (bad resolution) schematics from electrotanyahttps://elektrotanya.com/metex_ms-9150_sm.pdf/download.html, I measured a lot of voltages/references and components values they are okMAX134 datasheet clearly talks about half resistance measured value that must be multiplied by two by MAX134 itself or externally by microprocessor, so my idea is this operation doesn't take place.But the X2 (or called /2) operation is a bit set by logic dialog between MAX134 and uP , it seems strange to me something in this has broken...I cannot find the failure, I'm trying to repair it by more than a month and I'm almost giving it up.Any suggestion or already similar issue ?Thank you

author: MathWizard
author_rank: Super Contributor
timestamp: May 01, 2023, 05:57:42 pm
content: Here's a better copy bottom) of the schematic, fromhttps://www.eevblog.com/forum/reviews/metex-universal-combined-test-instrument-systemsstations-a-look-inside/Nice machine tho, with the combined DMM, PSU, counter, function genIDK about the uP or the other chips having problems. And I'm having a hard time seeing where the inputs and switches are are going. BUt I'd say on page 3, is where the reference current comes from. Maybe it's even from the max134, across those range selection resistors, just making a divider. Or some of those op-amps there near that chip, making a constant current, then then goes through some known range resistors ?If something really was wrong and you can't get that 2x mode to work. Maybe the analog circuitry would only need a little change, like doubling the reference current, or swapping a few range resistors, or changing the reference level on some op-amp, or changing it's gain. If it was some dual use circuit, you might need to add a switch as a by-pass, to a little PCB with your different resistors on it.
Goldstar DC Power Supply GP-4303D and Digital DCM DRP-303D LED replacement help - Page 1
Forum section: electronics / repair

author: guswin95
author_rank: Contributor
timestamp: June 29, 2020, 02:18:24 pm
content: Hello all,Long time reader, first time poster.I have a clone of the Goldstar DC power supply made by Digital DCM and there are a lot other clones of this popular format cheap variable power supply.For what they are, they work well and mine has many years of service. No fan, so completely silent and quite repeatable settings. Unfortunately the green LED display are failing. Initially it was one segment in one digit, but progressively it's gotten worse to the point most digits are affected. Although I got a replacement unit that is more modern (Korad), I kind of miss this one for its simplicity.I took it apart sometime ago, and all the LED displays have no markings at all and the pin configuration do not match classic standards that I could find online.I am asking here if anyone has a part number or a lead for a better description of where to buy replacement displays.Thanks

author: tunk
author_rank: Super Contributor
timestamp: June 29, 2020, 02:22:56 pm
content: It may help if you post a picture of the LED display itself (with pinout).

author: guswin95
author_rank: Contributor
timestamp: June 29, 2020, 03:18:23 pm
content: Here are some old pictures from when I took it appart.

author: guswin95
author_rank: Contributor
timestamp: June 29, 2020, 03:19:14 pm
content: A few more

author: youngwug
author_rank: Contributor
timestamp: June 30, 2020, 12:50:27 pm
content: Share what I experienced.

author: guswin95
author_rank: Contributor
timestamp: June 30, 2020, 01:04:08 pm
content: Thanks for the document. My power supply works properly and only has fading digits. I was able to trace some of the segments and validate they don't work.The pinout of these is quite different from all I have seen commonly shown foe sale. There are no markings at all on the modules so I am at a loss. Will take pictures of the unit assembled to show better the problem.

author: tunk
author_rank: Super Contributor
timestamp: June 30, 2020, 01:51:42 pm
content: Maybe something like this could be adapted, i.e. check pinout:https://uk.rs-online.com/web/p/led-displays/1246761/

author: guswin95
author_rank: Contributor
timestamp: July 01, 2020, 08:22:56 pm
content: Mostly looking for a direct replacement part to make the repair easy. Although an old PS, I hope the parts are still available if we had a part number to search for.I have been unable to find any documentation on these power supplies. I was hopping someone had used one and theirs had some markings on the seven segment displays to help the search.Keep hoping for an easy solution.
Goldstar GP 4303D Power Supply - Page 1
Forum section: electronics / repair

author: jrcurtis
author_rank: Newbie
timestamp: March 27, 2022, 05:40:25 pm
content: Am new user to the blog however been reading it and and watching on YouTube for years. Does anyone have a schematic or service manual for the GP 4303D Power Supply. I have a unit that works electrically, but the display jumps all around and cannot used to set the supply. Currently I'm using a DVM to set voltage and current limit, but would like to fix the display circuit. Any help would be appreciated. Jim
Good place to find replacement Fluke Scopemeter Parts? - Page 1
Forum section: electronics / repair

author: DreadfulGranola
author_rank: Newbie
timestamp: November 22, 2023, 08:56:53 pm
content: I have an older Fluke 99 Scopemeter Series II that I really like, but of course has that issue with the screen that I see alot. I've been looking on and off trying to find a replacementtransreflective display and EL backlight.I've looked everywhere I know to look, and have even tried to find parts for the Phillips counterpart. I'm just coming at a loss on results. Is there any place that sells known good replacement parts forthese without having to gamble on a 'for parts or repair' Scopemeter from eBay?

author: z2000
author_rank: Newbie
timestamp: December 21, 2023, 11:00:00 pm
content: For your referencehttps://areciv.com/blog/2013/02/fluke-scopemeter-97-el-backlight-repair/The 97 is not the same as the 99, but it can do similar. The EL panel is easy to find.
goodwill gps 4303 - Page 1
Forum section: electronics / repair

author: oulup
author_rank: Newbie
timestamp: July 31, 2020, 01:39:47 pm
content: Hi! I have here a broken goodwill gps 4303 power supply and I'd like to try and repair it. I still didn't try to turn it on. There was a message written on saying not to mount a fuse because it's broken, so I suspect some power device problems, it's quite probable they messed with the voltage change input switches. Anybody has got a schematic to share? thank you for the help.

author: cdev
author_rank: Super Contributor
timestamp: July 31, 2020, 01:51:04 pm
content: Could you shoot a better picture of the front panel? It looks a lot like the digital version of the GWInstek bench PS that I have. I want to see if it might be a clone of a power supply I may have a manual for.It probably isnt, but you never know. These power supplies are often very similar.

author: oulup
author_rank: Newbie
timestamp: July 31, 2020, 01:57:30 pm
content: here it is, the front plastic is missing, they threw it away, but you still can recognise the model i guess

author: cdev
author_rank: Super Contributor
timestamp: July 31, 2020, 02:09:16 pm
content: It looks very similar, with some slight differences.The manual I have thats similar is for a Tek badged PS with such similar layout that it may be useful, if not exactly the same.See attached file, Tek_PS280-283_Service_Manual_Schematics.pdf

author: oulup
author_rank: Newbie
timestamp: July 31, 2020, 02:11:57 pm
content: thanks: I'll read and compare
Google Nest Thermostat gen 3 WiFi issue - Page 1
Forum section: electronics / repair

author: DFCprime
author_rank: Newbie
timestamp: April 11, 2024, 12:32:04 pm
content: Hello all!My first post on the eevblog, with a question about some repair that I want to start.WiFi capability of my Nest Thermostat is dead for good, no network can be found and no connection with the control unit. I saw in reddit tones of topics with this issue and I start thinking on "could this problem be fixed".Had anyone this issue and found a solution, or I will be the first addressing this one? I will post pictures with the teardown and hopefully a fix, if I will found one.
Google Pixel 5 Blackscreen/Data recovery - Page 1
Forum section: electronics / repair

author: Michaelaudio
author_rank: Regular Contributor
timestamp: March 08, 2024, 09:55:13 pm
content: Hello everyone,i was charging my Pixel 5 when it suddelnly wouldnt turn on the screen anymore. The Phone itself seems to work fine. Touchscreen also works and my Notebook can detect it.I replaced the screen at first but thats sadly not the problem. So I have to get my Data out of it, since I have no experience in Phone repair (or Information about the Motherboard)I have tried several Options from usb Hubs with hdmi to Data recovery Programms. Does anyone have a clue how I could do it? Usb Debugging is not activated sadly.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 08, 2024, 10:13:01 pm
content: normally the usb debug is a way in, i dont know if theses can be accessed thru adb softwares .... i dont know if you have cell phone repairs boutiques near you, i would try to contact them if they have solutions ...and sadly always do a backup in cloud related services or sync with google if it was activated ??

author: Michaelaudio
author_rank: Regular Contributor
timestamp: March 08, 2024, 11:13:42 pm
content: I have, but its a little expensive, so I wanna try everything possible before that. I read something about abd, but im not familiar with that.Yea the Free storage wasnt enough so i havent used it..

author: Michaelaudio
author_rank: Regular Contributor
timestamp: March 09, 2024, 09:47:52 am
content: Or does anyone known how I can get Information of the Mainboard or this particular problem?Would be nice if I could repair it so i dont have to buy a new Phone.

author: hesam.moshiri
author_rank: Regular Contributor
timestamp: March 11, 2024, 06:05:11 pm
content: You mean the phone works and only the display went black?So look at the LCD FPC connector if you fit it correctly or if you have not damaged the LCD flat cable, check for the missing components near the LCD FPC connector

author: coromonadalix
author_rank: Super Contributor
timestamp: March 12, 2024, 02:11:16 pm
content: as i written ADB can or could help youhttps://android.stackexchange.com/questions/54272/how-to-perform-a-full-system-dump-backup-with-a-broken-screenXDA forums can help better than here

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 13, 2024, 03:40:10 am
content: Does a USB-C to HDMI adapter work?

author: Michaelaudio
author_rank: Regular Contributor
timestamp: March 14, 2024, 08:30:45 am
content: Yea the Phone works its just the display. Ive Googled many hours and tried everything to get an Image on my tv but nothing helped. I also asked in an xda forum.Since nothing would help I tried to look at the board myself, but since I have no microscope i gave up quickly and brought the Mainboard to an experienced Phone repair guy.I also thought about just solder the Flash to a new board, but that wouldt work either I would have to swap the processor too and things can go wrong there since im not a Micro solder pro
Gophert CPS 3205 II sporadic OUP errors - Page 1
Forum section: electronics / repair

author: Piotrix
author_rank: Newbie
timestamp: March 23, 2025, 11:40:57 pm
content: 5 Years ago I bought Gophert CPS 3205 II . I used it sporadically, I think all together less then for 1K Power On hours.And I am getting sometimes OUP Over Voltage Protection errors with nothing connected. Any tips?I think when I was scouring the internet I saw reports of smillar problems.I'm almost sure it is some manufacturer defect.I also wonder how common this failure is. And generally how reliable Gophert PSUs are? Especially in comparison to Riden RK6006-C

author: Gregg
author_rank: Super Contributor
timestamp: March 24, 2025, 12:01:13 am
content: The error is for the device under test is using more power than the settings you input to the Gophert. An off/on cycle clears the error and either increase the current limit or reduce the voltage before testing again.
Gophert CPS-3220 oscillation - Page 1
Forum section: electronics / repair

author: radud5
author_rank: Newbie
timestamp: December 30, 2020, 05:14:41 pm
content: Hi all,I have Gophert CPS-3220 without any schematic.I find inside TNY274 for permanent 12V and TL494GI have oscillation for low load:12V 0,08A ... 0,15A 0,27A ... 0,33A5V 0,04A ... 0,55A 0,73A ... 0,87A4V 0,04A ... 0,8A 1A ... 1,12A2V 0,03A ... 0,95A 1,2A ... 1,55A0,1A 2V ... 15VOscillation is stronger on low voltage.Please help me with solution to reduce oscillation on low load.Thanks,

author: HB9EVI
author_rank: Frequent Contributor
timestamp: December 30, 2020, 07:10:42 pm
content: too little info here; how do you know there are oscillation? did you scope it? can you show us?

author: radud5
author_rank: Newbie
timestamp: December 30, 2020, 08:28:45 pm
content: VideoI couldn't record the oscillation sound. It has a high frequency.

author: electr_peter
author_rank: Unknown
timestamp: November 23, 2021, 02:05:39 pm
content: I know this is an old topic, just wanter to clarify few points.Video above seems to show setup of Gophert CPS-3220 set to 5V at some high current limit, DL24P set to 0.1A CC load and some oscilloscope presumably connected to current shunt.After turning 0.1A CC mode on, load current oscillation is visible on both scope screen and current meter while voltage is rock solid at 5V.This indicates that DC load is oscillating, not Gophert PSU.DL24P electronic load is far from perfect, OP tried to improve itcheezeball-dc-load-dl24p-pump-or-dump

author: HB9EVI
author_rank: Frequent Contributor
timestamp: November 23, 2021, 06:17:27 pm
content: can be, cannot be. the video shows pretty much nothing, that's likely why there were no further replies.both devices, the scope and the load are just toys; you can hardly call that measuring, and TO didn't come back to thread, so it's nothing but speculationat least my Gophert 6017 works without any oscillation at any random current and voltage

author: electr_peter
author_rank: Unknown
timestamp: November 23, 2021, 06:29:01 pm
content: Well, provided data is sparse, this is my interpretation what's available.It is known problem (in general) for DC load to sometimes be unstable (especially at low 0.1A current for specific DL24P, see other threads). On the other hand, Gophert 3220 (capable of 32V/20A) probably didn't notice 0.1A load at 5V, PSU was in CV mode (current setting was higher). And there was 5V reading with or without load.Oscillation could occur if PSU is set up for CC mode or on CV/CC edge and loaded with active load, this was not the case.
Gopro Hero 8 black water damage repair help?? - Page 1
Forum section: electronics / repair

author: RP
author_rank: Newbie
timestamp: May 26, 2024, 09:29:02 pm
content: Hello there,I got a Hero black 8 badly water-damaged and sat like that for a month.It seems the water penetrated fully and damaged the PCB. corrosion can be seen all over the PCB connector. I have attached some pictures for reference.Same back story, I have recently moved country so I do not have my electronics lab, tools, or equipment with meall I have is a screwdriver set and a multimeter.So here is my plan first remove all the corrosion from the PCB using some common housing holds items like IPA and vinegar then check for short.Is there any other chemical that can remove the corrosion safely??

author: cold_zero
author_rank: Newbie
timestamp: June 08, 2024, 06:26:18 am
content: First off, you gotta remove all the covers.Second, in my country, I use hot thinner or alcohol 99% to clean the board. You can either brush it for a long time or use an ultrasonic cleaner.Then, dry the board with hot air. After that, apply flux and use the right amount of heat to melt and spread it under the IC, re-balling the solder balls.Be careful of high heat on the processor or flashFinally, before you power up the board, you need to check the traces and make sure there's no short circuit.

author: flolic
author_rank: Frequent Contributor
timestamp: June 08, 2024, 06:32:59 am
content: Don't even bother to fix that, it will never work again.Speaking after 10+ years of experience in camera repair business.

author: wraper
author_rank: Unknown
timestamp: June 08, 2024, 06:50:42 am
content: ^I repaired quite a bit liquid damaged phones in the past, does not look unfixable to me (the question is if it's worth the time and effort). However you'd need ultrasonic bath and experience soldering tiny stuff. Likely you'd need to remove some micro BGA.Quote from: cold_zero on June 08, 2024, 06:26:18 amUsing alcohol for that is counterproductive. It does not dissolve salts/corrosion. Not to say it's dangerous to use in ultrasonic baths and their manufacturers prohibit it if you read the manual.https://www.omegasonics.com/how-to/ultrasonic-cleaners-dos-and-donts/#:~:text=Never%20fill%20the%20tank%20of,or%20any%20other%20flammable%20liquids.QuoteNeeds to be water based cleaner solution, citric acid solution may work well enough if you don't have anything better (may damage the board if held for too long or concentration too high).
Gordak 952 no display/no heat - Page 1
Forum section: electronics / repair

author: AlinPaladin80
author_rank: Newbie
timestamp: November 24, 2024, 05:02:37 pm
content: Hello to everyone,Please help me with an opinion.I have a soldering station Gordak 952, the one with digital displays for both hot air and letcon temperature. The letcon side works fine.The hot air side stopped working after at most 10 hours in 2 years. No led for heating, no display, no heat. Only the pump is working, with its (indicator) led.The corresponding triac for heating has no power. Neither the octocupler. I suspect the IC is the culprit. Unfortunately it appears that the producer erased the IC label in order to protect the product from copying, and even so, it seems that the 20 pins ICs need programming and custom firmware. Which is out of reach, I can't find even the right schematic for this product. On the internet there is only one, with 14 pins ICs, not 20, and the connexions name differs, the triacs differs, and some PCB circuits are not the same.The question is: is it something I can try to do (in the eventuality it is not the ICs fault?) The PCB looks good, the components looks good, no cold soldering in sight.The display shows 250, then 150, all in a second or less, after connecting the unit to mains, turned off or not via switch. (I think this is the standard behavior? I can't remember precisely) After that there is no display at all, turning on or off.If the thermocouple is removed, the display shows an error (so the display has power), which doesn't go away by turning off via switch. If the pump or heater is disconnected, this changes nothing.Does this means a part of the IC is bad? Or it has some protection mode?Thank you for your time and patience.
Gossen Metrawatt 32EL300R30 electronic load - measured values way off  - Page 1
Forum section: electronics / repair

author: rockwell
author_rank: Regular Contributor
timestamp: November 30, 2024, 08:22:55 am
content: My Gossen electronic load has the problem that the measured values shown on the display are not correct.I opened the case and hoped that there are some labeled trim pots to adjust the measured values.So furtunatly I found 9 trim pots, but they are all unlabelled so I don't dare to touch them and mess up all settings.Does one know how to change this ?Or even knows if there is a service manual around, I checked google for this but didn't find anything.

author: bastl_r
author_rank: Regular Contributor
timestamp: November 30, 2024, 10:31:14 pm
content: Quote from: rockwell on November 30, 2024, 08:22:55 amAre only the displayed values wrong?So you have to check only the display or ist input.Edit: OK its a newer one. Forget the displaycheck.Manual:https://www.gossenmetrawatt.de/en/products/32-el-300-r30Regards

author: rockwell
author_rank: Regular Contributor
timestamp: December 01, 2024, 09:25:53 am
content: Yes, the voltage shown on the display is not the same as that on the input leads measured with a DMM.It's the same device as the Atten ATZ3711A, Array 3711A and Tekpower 3711A.
Gould 1425 Oscilloscope No Trace - Page 1
Forum section: electronics / repair

author: IanUK
author_rank: Newbie
timestamp: September 14, 2019, 04:18:11 pm
content: Hi allI have a gould 1425 storage scope that I got off E-Bay (Bought as not working )The scope switches on but has no traceThe heaters are on and I've checked the voltages except the -1800 volt line because I don't have the correct probebut I think I've found the problem in that NPN Transistor Q407 in the Y Amplifier, does anybody know if this could bethe culprit or do I need to look elsewhere?ThanksIan

author: benj38
author_rank: Frequent Contributor
timestamp: September 14, 2019, 07:13:05 pm
content: There is not enough information in your question to give much more than a general reply.Yes, a problem in the vertical amplifier can easily send the beam off the screen preventing one from seeing any trace.

author: tautech
author_rank: Super Contributor
timestamp: September 15, 2019, 09:06:40 am
content: Ian, OP, so we can all play along at home please post a link to the service manual you are working from.
Gould 1602 repair help - Page 1
Forum section: electronics / repair

author: noodlebear
author_rank: Contributor
timestamp: February 11, 2013, 04:42:35 pm
content: Hi,I've just acquired a Gould 1602 scope which has a problem. On power on, the power light comes on but there is no other activity. After leaving the scope running for a while and then turning off and on I occasionally see all the channel 1 LED's flashing and once saw the CRT flash.The service manual is available athttp://dl.dropbox.com/u/8513299/Gould%201602_1604_Service%20Manual.pdfand schematics athttp://dl.dropbox.com/u/8513299/Gould%201602%201604%20schematics.pdfI have had a look at the power supply voltages and all seem within spec. VAC on multimeter shows minimal ripple however I don't have another scope to test this properly.Going through the troubleshooting guide in the service manual the first thing to check is the 1MHz E clock on U1 (the main processor, MC68B09P). Since I don't have a scope to check this with I used the frequency counter on my multimeter. This shows a frequency of almost exactly 2MHz (not 1MHz).I wonder whether this could be a discrepancy in the service manual since it seems exactly double? Does anyone have any ideas as to how I could check this more thoroughly?Thanks

author: scirturbo
author_rank: Newbie
timestamp: June 08, 2013, 01:35:05 pm
content: Hi,I've repaired my 1604 several years ago and from what I can remember is that one logic circuit had a short and also several tantalium caps were low on resistance. It had also a out of focus image which was caused by dry caps in the powersupply. A couple of inputs had short/open components. A good start will be replacing all the tant. caps. Look for brown and hot caps.Hope this helps........Simon

author: Skeluroth
author_rank: Newbie
timestamp: May 20, 2020, 11:48:29 pm
content: Hello,yeah, i know this is a old thread but i have the exact same problems as you're describing it and i could not find anyone else with this problem.So i am wondering if you (or any other member) found a solution?
gould mgt 400 psu - Page 1
Forum section: electronics / repair

author: m3vuv
author_rank: Super Contributor
timestamp: March 01, 2022, 01:42:22 pm
content: Hi all,ivejust got this:https://www.ebay.co.uk/itm/224142076322 or at least one the same for spares,its built like a tank,i pluged it in and firstly a tant exploded followed by an mains rifa,the riffa's i just removed,the tant was across the remote sense terminals so cut that out too just for testing,now it seems to work ok,it puts out 5.01v,thing is i assume it is ok without the riffa caps,i will swap the tants for electrolytics as there is room,any idea what this would of been used for?,im not sure but i imagine its ok 40 40/50amps plus,i brought it just for the huge heatsink but seems to good too break!.TIA.

author: m3vuv
author_rank: Super Contributor
timestamp: March 01, 2022, 07:26:08 pm
content: just found out from seller its 5v 60amp also 12 10 amp,will the riffas input caps need to be fitted or just for emc reasons,,should be a handy psu for the £8 paid for it.

author: m3vuv
author_rank: Super Contributor
timestamp: March 02, 2022, 06:22:55 am
content: well i replaced the tants !)Uf at 25v with 47uf 50v electrolytics,not bothered with the riffas,found out it has 2x 17.5v max 8a each both adjustable and 2x 5v outputs 60A max,each is adjustable with 10 turn trimpots,should be a hany piece of kit,shame its a switcher,it weighs 14kg,its a beast!
Gould OS 253 no trace? - Page 1
Forum section: electronics / repair

author: Panini23
author_rank: Newbie
timestamp: May 10, 2021, 08:02:19 pm
content: Hello, I am a Finnish electrical engineer in Finland so sorry for bad English. Also my oscilloscope experience is quite small.I bought a Gould os 253 analog oscilloscope from a private seller. The seller told me it was working and in the picture it had a dot in the middle as it should.When I brought it home and plugged it in, I didn't the trace to show normally no matter what I tried. I also tried the same "settings" as shown in the picture of the seller.I was able to get the trace to show for a brief second when I turn on or off the oscilloscope as shown in the video below.https://youtu.be/r1RAKZxj6A4I opened the oscilloscope and measured voltages that were in circuit and transformer, but not the HV because my multimeter doesn't work with HV. Voltages were in few percent range. But there is acalibration knob in the front that should be 1V but I got 0.48V. Is the problem in my "settings" (trace positioning) or what I should try next?

author: YetAnotherTechie
author_rank: Regular Contributor
timestamp: May 12, 2021, 11:56:11 am
content: First things first:If it exists check the mains power selection is correct.Check the AC value on the DC voltages of the power supply, should be 10's of mV or less. Don't mess with HV power supply, from your video, it didn't look bad.Are there any inputs on the back? is there anything plugged in them?Unplug and replug all internal conectors. Don't do this for the crt gun connector, just gently push straight in if it's slanted. don't touch the suction cup, if it's not sparking it's fine as it is.I googled and got a similar (but not the same!)scope fromhttp://bee.mif.pg.gda.pl/ciasteczkowypotwor/Gould%20Advance/OS250.pdfUse the settings from page 5, section 3.2, with nothing plugged in you should get a trace, if not toggle the "bright trace" button repeatedly.If you don't get a trace go to page 6, section 3.7, you need a function generator, feed the same signal to both inputs, but set the volts/cm to be one step different from X to Y. You should get a lissajoux figure. If not toggle all switches back and forth a few times.Post results.
Gould TC20 counter info - Page 1
Forum section: electronics / repair

author: Big JJ
author_rank: Newbie
timestamp: June 29, 2020, 03:16:30 pm
content: HiQuite new to the forum but not to repairing test equipment. Used to work for Wayne Kerr in Bognor building and fixing stuff.I have a number of Gould bits of kit which I have had to decades, since last century!!!! Been fixing the scopes for years, Telequipment and Gould.My TC 20 counter has been stored up for a while during a move, got it out to check it over and it does not work.I am not sure if I ever had the manual but cannot find it now anyway. It has never gone wrong before!!!Have spent hours going through the sites listed without success, found a slightly early model but many differences.Gould usually provide good info for their kitSo if anyone can help with any info on a GOULD TC20, that would be appreciated
GP1250 diode equivalent - Page 1
Forum section: electronics / repair

author: set4d
author_rank: Newbie
timestamp: August 14, 2020, 02:20:02 pm
content: Hi, new to the forum so please be gentleI've got an amp on my bench that's come in for repair. I've found a blown GP1250 diode but can't for the life of me find a UK supplier for a replacement. Can anyone suggest an equivalent replacement please or, better still, a UK supplier?Many thanks,Rich

author: Pete66
author_rank: Regular Contributor
timestamp: August 14, 2020, 03:28:16 pm
content: I think you will have to buy in bulk:https://www.ebay.com/itm/ROLL-OF-4561-NEW-OLD-STOCK-DEC-DIOTEC-SOFT-GLASS-DIODES-GP1250-T-R/333382714072?hash=item4d9f2882d8:g:6JcAAOSwsbhdvITY:sc:FedExHomeDelivery!60633!US!-1Maybe ask the seller if they can sell you a few.What is the function of the diode in the circuit? Is it part of a bridge? Does it really need to be 2500V Reverse voltage?

author: Audiorepair
author_rank: Frequent Contributor
timestamp: August 14, 2020, 03:48:16 pm
content: Looking at the Forward Voltage figures in the datasheet, this device looks like a string of diodes in series in one package.You may be able to replace with several single diodes in series.https://www.digchip.com/datasheets/parts/datasheet/131/GP1250-pdf.phpI'm guessing this diode is on the OPT of a valve amp?

author: Audiorepair
author_rank: Frequent Contributor
timestamp: August 15, 2020, 07:38:00 pm
content: Well, we know nothing of the circuit that this diode comes from, but I have seen this diode used on valve amplifier OPT's, and can be got from Farnell.It is 4kV.https://uk.farnell.com/vishay/gp02-40-e3-54/rectifier-std-0-25a-4kv-do-204al/dp/2335149

author: set4d
author_rank: Newbie
timestamp: August 17, 2020, 08:48:59 am
content: Thanks for this. Yes, It's from a guitar amp.

author: Pete66
author_rank: Regular Contributor
timestamp: August 17, 2020, 09:05:40 pm
content: The Vishay diode is 4kv but he forward current is half of the GP1250.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: August 17, 2020, 09:51:18 pm
content: We still don't know what this diode is doing.If it is catching back EMF spikes, it is reversed biassed, no forward current.
GPS-3030D - Page 1
Forum section: electronics / repair

author: click381
author_rank: Newbie
timestamp: November 23, 2024, 05:05:04 pm
content: I have the Instek GPS-3030D The first digit of the display keeps jumping around from Volts and Apps anything can be done. Thanks

author: floobydust
author_rank: Super Contributor
timestamp: November 23, 2024, 06:07:53 pm
content: Welcome to the forumsThis PSU has many different styles, can you post a pic?What do you mean "digit" this is the LED number display?There are CC and CV LED's, and LED's to show the switch for displaying amps or volts, if this is a one display model.
GPS vs WWV data stream - Page 1
Forum section: electronics / repair

author: WA4AOS
author_rank: Newbie
timestamp: June 10, 2021, 07:03:00 pm
content: I understand WWV will shut down operations soon and there are groups trying to get the feds to continue to fund this viable service.Does anyone know if the data stream used on GPS is the same as used with WWV? I'm considering a very low 1mv DDS transmitter for 5 or 10 MHz and feed the GPS data into the xmitter. My need is to keep my old Heathkit GC 1000H clocks going wo retrofitting each unit with a GPS rx.Any thoughts?Glenn WA4AOS

author: fourfathom
author_rank: Super Contributor
timestamp: June 10, 2021, 08:32:53 pm
content: I think this WWV shutdown story is old news, and never came to pass. There was a 2019 federal budget proposal that would have shut down WWV transmitters, but that wasn't approved, and as of 2020 WWV funding seems to be adequate. I even see that there was a 2021 WWVB upgrade, supposedly completed a few months ago.

author: james_s
author_rank: Super Contributor
timestamp: June 11, 2021, 04:56:44 am
content: I hope that's the case. I also have a GC-1000, it's one of my prized possessions. I also have about half a dozen devices that rely on the 60kHz WWVB signal. Most people probably don't know what WWVB is, but there are hundreds of millions of "atomic" clocks that rely on it to work.

author: james_s
author_rank: Super Contributor
timestamp: June 11, 2021, 09:51:21 pm
content: They are indeed unrelated, WWV, WWVH and the GPS satellites each have their own independent array of atomic clocks. The clocks themselves should be comparably accurate but in practice GPS is likely to be more accurate due to propagation characteristics of the shortwave and LF broadcasts that WWV uses.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 11, 2021, 11:12:21 pm
content: As one might say, it depends on what you mean by "more accurate."QuoteGoogle: Difference between UTC and GPS timeIn terms of UTC, WWVB is more accurate.

author: MIS42N
author_rank: Frequent Contributor
timestamp: June 12, 2021, 09:50:05 am
content: There is a relationship between the time provided by GPS receivers and the various WWx broadcasts. The GPS time does not have leap seconds because it complicates the navigation calculations. However the GPS transmissions give the offset between GPS time and UTC so a GPS receiver reports time in UTC. The GPS and WWx broadcasts are related back to NIST. Seehttps://www.nist.gov/pml/time-and-frequency-division/time-distribution. The conversion of GPS data to WWVB format has been tackled, seehttps://www.anishathalye.com/2016/12/26/micro-wwvb/Deriving time from GPS is probably better than using the WWx broadcasts because the propagation delay correction has already been worked out by the receiver, the time should be within 100ns. Unless you know the distance between the WWx transmitter and your receiver to better than 30 meters, the GPS should win.
GPSDO TRIMBLE NAVIGATION 45321-0 | Nortel NTBW50AA - Page 1
Forum section: electronics / repair

author: AG6AV
author_rank: Contributor
timestamp: August 02, 2025, 10:25:07 pm
content: The GPSDO has worked for about 10 years, but now it is reporting the wrong date/time. The date is off by 19.6384 years. I believe this is a firmware issue, but I have not found a ROM on the web. I would appreciate help getting the current firmware/ROM.I have found documentation and software onhttps://www.ko4bb.com/getsimple/index.php?id=manuals&dir=02_GPS_Timing/Nortel_GPS.For reference, the GPSDO identifies (*idn?) as:TRIMBLE NAVIGATION,45321-0,80565742,3.75,A0827372,NTBW50AA,08Manufacturer code: TRIMBLE NAVIGATIONModel number: 45321-0Serial Number: 80565742Firmware Revision: 3.75Common Product Code: A0827372Nortel Pec Code: NTBW50AARelease Number: 08Please,Nathan Haltman AG6AV

author: sanleontexas
author_rank: Contributor
timestamp: August 02, 2025, 10:35:39 pm
content: Yep, sounds like the rollover glitch. Seems to affect different GPSDOs differently.

author: edpalmer42
author_rank: Super Contributor
timestamp: August 02, 2025, 11:35:26 pm
content: AFAIK, it's 1024 weeks after whatever date they put in their firmware. It was an issue with the GPS system rather than a bug in the receiver. They didn't expect systems to still be in use after 19 years. I believe the GPS system has been extended to prevent the problem with newer systems.For older systems, the fix depends on the usage. If you're using it for an NTP server, the driver may have been patched to compensate for the problem. If that's not possible, the only thing you can do is set the year to give you the same weekly pattern as now. If you look at a calendar for 1997, you'll find that the second of Aug. is Saturday, just like today. The year will still be wrong, but everything else will be correct. If the GPSDO loses power, it may get confused and you might have to manually give it a location, and a date and time that's within its 1024 week window.The output frequency and time reported will always be correct, even without doing anything.
GPU Component Identification - Page 1
Forum section: electronics / repair

author: Toblerone
author_rank: Newbie
timestamp: April 02, 2021, 11:06:56 pm
content: I'm trying to repair a 2080Ti GPU.In the red circle there are 3 missing components which I believe are MOSFETs the same as the one in the yellow box.Can anyone identify the exact type of MOSFET they are so I can order some please.Also I am looking to confirm the identity of some other chips.The green box I believe to be an inductor.The blue box I believe to be the power control SIC.And the purple box to be filter capacitors.Am I correct?All help gratefully received.

author: Bud
author_rank: Super Contributor
timestamp: April 02, 2021, 11:18:11 pm
content: The part in the yellow box appears to be a tantalum capacitor to me.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 03, 2021, 07:42:11 am
content: can you zoom pictures of them, you seem to guessed rightnot sure if the yellow are diode or capacitors, but the capacitors have polarity on them, i think they are high speed switching diodes ?? or they have more pins

author: Bud
author_rank: Super Contributor
timestamp: April 03, 2021, 06:14:46 pm
content: Looking to the left of the GPU, same components appear to be marked with "Lxx" , three of such designators for each part. Could that be an inductor network? Weird, i never seen several inductors packed in a single part.
GPU  Gigabyte N1030OC dead - Page 1
Forum section: electronics / repair

author: enito
author_rank: Newbie
timestamp: October 09, 2020, 10:47:35 pm
content: Hi,Im trying to repair this dead GPU, not working. Only i get 1 beep and 3 shorts, no screens. Where i can start to check with multimeter? any advice i thxfull a lot, if you need some pictures let me know..regards!!

author: Jasonbit
author_rank: Regular Contributor
timestamp: October 09, 2020, 10:53:08 pm
content: Maybe the problems is video card (same as the GPU is onboard).Check the means of the beeps on manual board (I thinks the meaning is universal).See this links:1-https://www.pcmag.com/encyclopedia/term/beep-codes2-https://www.computerhope.com/beep.htm1 Beep - Refresh Failure Reseat/replace memory, troubleshoot motherboard.3 short Base 64 K RAM failure.

author: enito
author_rank: Newbie
timestamp: October 09, 2020, 10:55:42 pm
content: Quote from: Jasonbit on October 09, 2020, 10:53:08 pmThx for reply, this MB have internal GPU and working, the problem is with this external GT 1030 , is not working. When i setup for only work with external,bios beep tell me problem with the gpu card. I want try to fix this one, i tested in another computer and same result. Where i can start to check with multimeter in the bad gpu card? thx

author: Jasonbit
author_rank: Regular Contributor
timestamp: October 09, 2020, 10:59:21 pm
content: Quote from: enito on October 09, 2020, 10:55:42 pmHooo, sorry, I don't repair the title of the topic.I don't understand how you can solve this problem (sorry). Because I thought the bips and meanings is the same to all configuration hardware.You already researched about repair on youtube?https://www.youtube.com/results?search_query=GPU+Gigabyte+N1030OC+repair
Gpu short on 2.5v caps - Page 1
Forum section: electronics / repair

author: r.asim
author_rank: Newbie
timestamp: June 28, 2020, 01:23:55 pm
content: I have two identical gpus, one of them is working, other one says short on 2.5v caps, i know they are short to gnd because the working one doesn't have a short there, i tried applying voltage to see what heats up, nothing does. All of the mosfets seems okay and fine, I will be posting images shortly

author: r.asim
author_rank: Newbie
timestamp: June 28, 2020, 02:09:40 pm
content: Pictures Attached, all 2.5v caps are shorted to GND, 16v Capacitor and All the mosfets are also good

author: r.asim
author_rank: Newbie
timestamp: June 29, 2020, 12:12:31 pm
content: Is there anyone who can point me in right direction? I don't know where to start as i can't identify voltage regulators or pci controllers in this circuit mentioned in repair videos on internet, also wanna know if applying 4v from li-ion cell was a bad idea since its some 1v line judging by the 2.5v caps?
Grant Squirrel 1203 Data Logger repair - Page 1
Forum section: electronics / repair

author: DeepLink
author_rank: Regular Contributor
timestamp: January 16, 2020, 05:39:25 pm
content: My trusted datalogger is dead :-(It's a Squirrel 1203 from Grant instrumentsMine is with 8 analog and 8 TC inputs, very useful (when it works)I've searched everywhere, but can't find any service manual / schematics (I do have the users manual)Any info is welcome

author: rvalente
author_rank: Frequent Contributor
timestamp: March 30, 2020, 07:41:58 pm
content: Did you open the device and checked the obvious stuff?Power supply and clock?

author: trobbins
author_rank: Frequent Contributor
timestamp: March 30, 2020, 10:58:33 pm
content: Try their service department, they sent me a SQ2020/2040 Mk2 Data Logger Service Manual service manual as the closest manual to my 2010. My LCD display wasn't working and I couldn't connect via USB - but RS232 was working. Resoldered/checked LCD display connector, and now back to normal.
Graphic card repair - SMD parts - Page 1
Forum section: electronics / repair

author: ltktomas
author_rank: Contributor
timestamp: June 19, 2020, 10:56:00 pm
content: Hello guys,I have just got a graphic card (ASUS GTX1070) to repair.Its owner managed to damage the bottom side of the card and now it freezes when under load.This is probably caused by some SMD parts missing at the bottom side right next to power sensing.I managed to get the same card so I would be able to compare what exactly is missing, but I'm not able to identify these two SMD parts:1) SOT23 marked asWCJ(EQ97, Q503)2) (most likely) SOT363 marked asK6ND2(Q526 on PCB)Does anyone have any idea what this could be?

author: fzabkar
author_rank: Super Contributor
timestamp: June 21, 2020, 04:53:22 am
content: MMDT3904, Diodes Inc, dual NPN transistor, 40V, 200mA, marking K6Nym, SOT363:https://www.diodes.com/assets/Datasheets/ds30088.pdf