hybridfree/eevblog-posts huggingface dataset:
Sidewinder X8 mouse charging issue, but fuses are OK... - Page 1
Forum section: electronics / repair

author: rooky
author_rank: Contributor
timestamp: October 29, 2017, 07:34:31 am
content: Hi expertsI need some help with a smd label.I have a SideWinder Mouse X8 where the charging is not working. blown fuses I did repair already. On the charging cradle, connected with the PC, there is a SOT-23 / SOT-323 part labled ADGV 2c which has the marking M1 on the PCB next to it. This part is connected to the red/middle wire of the cable normally. Barging the mouse. I assume this to be the 5v supply of the mouse, but non Lethe 3 pins of the charging wire has a voltage( all 0V).Does anyone have an idea what part this "ADGV 2c" is. NPN/pNP or MOSFET n-/p-Channel transistor???Does anyone know the pinning of the 3 connections of the charging cable which connects with a magnet to the mouse?Thanks a lotbest regardsRooky
EVGA Video memory repair [770 GTX / 980TI] - Page 1
Forum section: electronics / repair

author: coquinho
author_rank: Contributor
timestamp: October 27, 2017, 03:36:56 am
content: I have 2 EVGA boards, both have similar problems - but is a little more complicated than that. I tried theses repairs with interval of months, boards that came some time apart to my repair shop. Now I decided to share that I have done, maybe someone here have some idea about it.1. The two boards had memory short circuit, but on the 980TI, the short was very visible, memory VRM had exploded a high Mosfet, shunt resistor, 12V inductor, total short on memory bank. On the 770, the VRM was fine, giving 1.5/1.35V normally, but the board had artifacts all over the screen, memory bank was measuring 2-3 ohms, instead of 70, 80+ ohms that is more usual.2. I fixed the 980TI VRM, and replaced all memory modules with identical chips. I did the same with the 770, replaced all the memory chips.3. Both video cards now can work normally without the driver, but when running the driver, massive artifacts on the screen, and crash. I discovered that with lower memory clocks, below 810mhz, both boards become stable. I tested benchmarks and games, no crash at all.4. I reballed the 980TI chip - no result, same problem.5. I changed the 770 GTX chip by other - no result, same problem.6. I compared measures points on the 770 GTX with other board identical, and the measures was very similar between then.Anyone have any idea why with high memory freqs the boards become unstable? I tried to read some schematics of notebook that uses discret GPUs (AMD Venus, etc) but I didn't find much to help. I just want to find what it is, I think that is some knowledge that could help in the future with other cards...Anyway, Thanks for the attention

author: Rasz
author_rank: Super Contributor
timestamp: October 27, 2017, 07:42:00 am
content: where did you get new memory? did you pull them yourself from dead cards, or sourced from china? chinese chips will most likely be remarked to look like faster parts

author: wraper
author_rank: Unknown
timestamp: October 27, 2017, 03:58:38 pm
content: Quote from: coquinho on October 27, 2017, 03:36:56 amSeems that you don't value your time. If there was low resistance, it should be quiet easy to figure out which chip is bad as it will heat up a lot more than others when power is applied (from lab PSU if VRM is blown). I would guess you got chips with either remarked speed grade, model or even remarked chips made by different manufacturer (can check manufacturer with GPU-Z). IMO you can either replace those chips or try different GPU bios which is compatible with your card as it may have support for chips you used or have more loose vram timings.

author: TiN
author_rank: Super Contributor
timestamp: October 28, 2017, 04:01:15 am
content: Did you use same memory model/part number parts for replacements. Different memory chips often require different timings/settings to run properly on full-speed mode (which you get once driver is initialized).
IFR 100S Service monitor capacitors - Page 1
Forum section: electronics / repair

author: suenrod
author_rank: Unknown
timestamp: November 05, 2017, 02:43:34 am
content: I have an IFR 1000S service monitor with a fault in the SMPS (duty cycle regulator as IFR called it).It uses exotic 4 lead low ESR caps. I'm pretty sure it's going to be a bad cap due to the age of the unit.The SMPS runs at 20khz. How do I figure out how low the ESR should be?Thanks,Rod

author: SeanB
author_rank: Super Contributor
timestamp: November 05, 2017, 06:35:41 am
content: Just replace with a regular low ESR modern capacitor, which is almost guaranteed, for a regular panasonic, Nichicon or other reputable manufacturer, to have a lower ESR than the originals. just use a wire jumper to bridge out the input and output leads on the capacitors, and it will work perfectly again. 20kHz 30 years ago was a hard thing for wound electrolytics with a single long tab to do, but modern units in a radial package have absolutely no issue with this, just use ones rated for more than the current drawn on the rails, and if not sure just use a value and voltage slightly higher than the original and in a similar diameter and length case ( smaller than original by up to 30% in any dimension will be fine though) and you will be fine.I have some really old 100uF 6V capacitors, that are 2inches long and an inch diameter, and I thought that the dimensions had been entered incorrectly, but no they are that, just that they are a regular capacitor from the 1960's, with a rotten compared to modern performance, but back in 1960 they were a good unit.
Schneider variable speed drive ATV12 - Page 1
Forum section: electronics / repair

author: Berserk
author_rank: Contributor
timestamp: October 27, 2017, 05:50:36 pm
content: Hello, can anybody gave me advice about recovering Schneider ATV12H075M3? It was burned down after power surge, got exploded capacitor and one burned electrical path and i think probably something more, but i hope damaged only power supply circuit.Current state of device is short circuit, after add input 240v it just shut down protection switch 16aSadly i am noob at diagnostic of burned electronics, but i want to learn ) I'll be glad to read any advices

author: oldway
author_rank: Super Contributor
timestamp: October 27, 2017, 06:15:03 pm
content: Welcome to the forum.These variable frequency drives are modular and they are not designed to be repaired, but simply replaced by a new one.This is power electronics with dangerous voltages.It requires adequate equipment to work safely as isolation transformer and differential probe.In addition, I think it will be difficult to find schemas or service documentation.

author: Berserk
author_rank: Contributor
timestamp: October 27, 2017, 06:23:04 pm
content: I know it is difficult task and i will never work with it without proper safety measures. Do you think it's possible to recover it without documentation?

author: oldway
author_rank: Super Contributor
timestamp: October 27, 2017, 06:51:00 pm
content: If it is only the power circuit, probably yes, at least for someone who has knowledge and experience on this kind of equipment.But one of the problems is finding spare parts .... they can also be very expensive.From your description of the problem, it would surprise me that damaged circuits are limited to power circuits.Such equipment is very cheap and is probably damaged beyong economical repair.A new one can be found for only 102.25 euros !https://www.plc-city.com/shop/fr/schneider-electric-variable-speed-drives/snr-atv12h018m2-nfs.html?gmc_currency=1&gclid=CjwKCAjwssvPBRBBEiwASFoVd2pagKoYgHIgCrgd-GktfqBRrwWkztjHmwTB0ZK-iSlzCHVK_7LyTxoC0ogQAvD_BwE
Android motherboard LM removal/repair - Page 1
Forum section: electronics / repair

author: Seaofdep
author_rank: Regular Contributor
timestamp: October 26, 2017, 05:15:41 pm
content: Okay so I have a android motherboard that needs l4950ts replaced , I have a rework station and have done such task before but never one with so many components so close. Any advice,precautions, preparations , tools needed best heat temp for air gun any advice in general. Thank you in advance for the helpSent from my iPhone using Tapatalk

author: Armadillo
author_rank: Super Contributor
timestamp: October 26, 2017, 05:44:18 pm
content: 15mm x 10mm device with such ample space around is generous spacing, so no need to be afraid of it at all. You may be dealing with lead free solder and multi layer boards, so expect higher heat setting but maybe just 2 layers ....lucky you...One advice I can give you, protect those plastic connectors nearby, I mean PROTECT it with generous high temperature Mylar tape.

author: Seaofdep
author_rank: Regular Contributor
timestamp: October 26, 2017, 05:51:34 pm
content: Quote from: Armadillo on October 26, 2017, 05:44:18 pmThat s a relief I have been sitting on this for a while now as build up experience and I finally got around to ordering the piece , okay I'll be going to go get some Mylar tape in a bit . And now it's the waiting game for usps lolSent from my iPhone using Tapatalk
Anybody have a Tektronix TDS7054 or TDS7104 with serial prefix B04XXXX? - Page 1
Forum section: electronics / repair

author: Jwalling
author_rank: Unknown
timestamp: November 16, 2016, 11:24:13 am
content: I'm looking for what Intel chipset is used on serial prefix B04XDoes anyone have one of these that could check for me? Even a serial prefix of B05X may be helpful if they used the same motherboard...Thanks!

author: skennedy
author_rank: Contributor
timestamp: November 17, 2016, 01:12:51 am
content: We have a DPO7104 with serial B05X. I'm not sure it will be much use to you but the serial is in the same range. It's a university owned scope so I can't open it. The device manager tells me it has a 82945G chipset and an Intel P4 3.4GHz processor.

author: TheSteve
author_rank: Unknown
timestamp: November 17, 2016, 08:08:10 am
content: I have a TDS7104, serial # B0424XX - it has the Intel 82810 chipset.Had Win98 when I got it, installed XP, upgraded the ram, installed an IDE SSD and faster CPU, it is working great.

author: Jwalling
author_rank: Unknown
timestamp: November 17, 2016, 11:42:23 am
content: Thanks skennedy and TheSteve.Interesting - an image I had saved from a serial prefix B040 would get a stop 0x7B on a scope with serial prefix B010. For future reference, the B010 prefix uses a 82443BX chipset with a 82371AB/EB IOCH. I ended up using Terabyte's OSD tools to install the IDE drivers.

author: TheSteve
author_rank: Unknown
timestamp: November 17, 2016, 05:45:13 pm
content: There are two different mother boards for sure, you can tell which is which by looking at the back plate and location of the ethernet jack.I believe they are detailed in one of TiN's threads.

author: limpkin
author_rank: Newbie
timestamp: October 26, 2017, 10:13:12 am
content: Hello!Do you still have by any chance all the install cds and drivers?Thanks!
component identification - Page 1
Forum section: electronics / repair

author: angelothewolf
author_rank: Contributor
timestamp: October 25, 2017, 06:43:48 pm
content: Hi! can anyone helpme idntify this thing?!

author: ataradov
author_rank: Super Contributor
timestamp: October 25, 2017, 07:00:17 pm
content: 5 seconds of google - MAX4647EUT-T+.This is the first result on "aarv 6 pin".On a bigger picture, it looks like the last letter is W, which would make it MAX4648EUT-T+
Nissan Bose Buttons Not Working - Page 1
Forum section: electronics / repair

author: harveyy
author_rank: Newbie
timestamp: October 27, 2017, 07:21:56 pm
content: Hi Guys,Newbie here! My Nissan Bose Radio/CD/Cassette (PN 2261F) unit functions but the buttons stopped working. It started with just one non-working button for a month and just last week no buttons work.Any ideas where to look would be a start.Much appreciated!Harvey

author: oldway
author_rank: Super Contributor
timestamp: October 27, 2017, 08:08:51 pm
content: Welcome to the forum.....This is a common problem on many modern devices like CD players for example.Behind the button, there is a micro-switch.It is these micro-switches that wear out and do not make contact anymore.You have to look for the service manual and disassemble the device to replace the micro-switches ...Be aware that there are many models of micro switches .... you have to look for the same on ebay.

author: Twoflower
author_rank: Frequent Contributor
timestamp: October 27, 2017, 08:26:23 pm
content: Welcome!Since the buttons seem to fail all over the place within a short time I don't think it's the switches. I would guess more like a problem with a (flex-)cable that connects the board containing the switches with the board containing the CPU.But how to get to the connection requires some carefully look and test. Unless you find a service manual or a tear-down instruction somewhere. Depending on the design it can vary from extremely easy (like marked screws) to near impossible to do this non destructible (plastic clips that to easily break of). Maybe you can get a defective model (best with a different defect) for little money. Here you can try how to open it and get to the places you want with this device first. It also can later donate parts if needed.
Hitachi V-525 assistance required - Page 1
Forum section: electronics / repair

author: Specmaster
author_rank: Super Contributor
timestamp: October 25, 2017, 08:41:00 am
content: Does anyone know how to remove the plastic part on the pivots of the handle on this scope please? I need to remove mine in order to gain access to the screws that hold the assembly to the case?

author: Specmaster
author_rank: Super Contributor
timestamp: October 25, 2017, 08:48:15 am
content: Its OK, I solved it by brute force and ignorance, thanks.
Part identification help :) - Page 1
Forum section: electronics / repair

author: kalinga
author_rank: Contributor
timestamp: October 23, 2017, 03:16:59 am
content: Hey guys!i need some help identifying an SMD component,https://photos.app.goo.gl/9KHmOZSo5B00Moou1this is part of a PWM charging controller UC3843BN, when i check other components, i can see following with same 44https://photos.app.goo.gl/g8ka3rVyvCMrDV9m2issue is, i've see few version of L44's, last 2 digits are different, above is L44 1/3 but I've seen L44 0/7 as well, since the burn part has the 7 on it.the L44 marking mostly refer to BAT54S (PLANAR SCHOTTKY DIODES)but what does the last 2 digits mean ?

author: dave_k
author_rank: Frequent Contributor
timestamp: October 23, 2017, 10:33:31 am
content: The last 2 digits are probably the date code of when it was manufactured ..

author: kalinga
author_rank: Contributor
timestamp: October 24, 2017, 04:06:41 am
content: Hey dave,i was thinking the same, thanks!
Solar King SLK-4000 4KW Grid Tie Inverter Repair - Page 1
Forum section: electronics / repair

author: Photon939
author_rank: Regular Contributor
timestamp: October 23, 2017, 01:32:39 am
content: I've been looking at doing a solar installation for my house and came across this inverter for $100 on ebay. It claimed the inverter had "RELAY FAULT" on the LCD which was shown in photos. I think to myself cool, this could be an easy fix.Check out the bodge capacitors on the gate driver IC

author: Photon939
author_rank: Regular Contributor
timestamp: October 23, 2017, 01:38:25 am
content: I found it interesting that the main transformer is potted in a block of silicone way off to the side.So I get to work taking out all the screws and popping all the power devices loose. Hello, what do we have here? Seems one of the devices got the ass blown out of it. Fairchild HGT40N60A4 600v IGBT, neat. Looks like I can still buy one from mouser for $13. I hope the gate driver IC hasn't died with it. Maybe I should order one of those just in case.The traces between collector and emitter are gone. Main fuse still A-OK though. Makes sense though, there's a crapload of capacitance on the main rail. Probably made a good bang when it went.

author: WastelandTek
author_rank: Frequent Contributor
timestamp: October 23, 2017, 01:42:15 am
content: I hate stuff like this, seems like every time I stuff new parts in an inverter they instasplode on powerup.

author: DaJMasta
author_rank: Super Contributor
timestamp: October 23, 2017, 02:57:43 am
content: Some good old high energy damage going on, but is that a shriveled cap in the first post or did the back of it blow out like a balloon.... haven't seen that one before

author: Photon939
author_rank: Regular Contributor
timestamp: October 23, 2017, 03:59:35 am
content: Quote from: DaJMasta on October 23, 2017, 02:57:43 amIt's just two caps glued together with some of that brown snot glue.I just found another failed IGBT, it seems the one that a chunk blew out of is not the same as the one that blew the traces off. Seems one failed open the other failed short. Short to all three terminals. I will almost definitely need to replace the gate driver IC. Mouser's stock of those is currently backordered until Nov 3. Bleh. Maybe I can use that time to see if I can get an equivalent IGBT that is a bit cheaper.

author: Photon939
author_rank: Regular Contributor
timestamp: October 24, 2017, 05:17:27 pm
content: Sorry for double-posting but considering the IGBTs used in this inverter are $13/each would it be possible to substitute? Mouser has other IGBTs that have the same current and voltage ratings for much cheaper although their max power dissipation is lower. Original IGBT is a Fairchild HGT40N60A4.I haven't had to substitute an IGBT before. Seems they don't list anything like gate capacitance or anything so are there any critical values to watch for?ThanksThis one seems to be the best substitute I've found so far:https://www.mouser.com/ProductDetail/IXYS/IXXH80N65B4/?qs=sGAEpiMZZMv4z0HnGdrLjtBI7mva2f6RCLszTNq3UfA%3d
HP 54501A Oscilloscope firmware - Page 1
Forum section: electronics / repair

author: TimInCanada
author_rank: Regular Contributor
timestamp: October 24, 2017, 09:33:22 pm
content: Attached is the firmware files for the three EPROMs in the 54501A, in case anyone in the future is looking for these.Also uploaded to KO4BB.Cheers,Tim
Circuit diagram for studio flash NiceFoto 230 and NiceFoto 680a - Page 1
Forum section: electronics / repair

author: swetlio
author_rank: Newbie
timestamp: October 23, 2017, 06:20:04 am
content: Hi all, I'm looking for circuit diagram for this two models studio flash NiceFoto 230 and NiceFoto 680a -Can somebody help me?
Help me identify a temperature sensor (Goot PX-201) - Page 1
Forum section: electronics / repair

author: SomeUser
author_rank: Newbie
timestamp: October 23, 2017, 05:03:22 am
content: HiWhat kind of temperature sensor does the PX 201 ceramic heater have ? I've seen a voltage reading AND a resistance reading (both increasing with temperature) on the sensor leads wrt to temperature.Many Thanks for any pointers
Tonghui TH2821B LCR meter "No Or" error? - Page 1
Forum section: electronics / repair

author: Jwalling
author_rank: Unknown
timestamp: September 15, 2017, 02:16:30 pm
content: Went to use this this morning and it powers up with this error message.Naturally, what passes for a manual does not list this code. New battery, and removing the battery for an hour does not change anything.Does anyone know what this means, or what might be wrong?Thanks.

author: Jacek_Paw
author_rank: Contributor
timestamp: September 15, 2017, 05:24:16 pm
content: I had the same problem with my RLC meter and it was caused by the lack of communication between analog and digital board. To be honest I don't exactly remember how I figured it out, but I'm sure that xtal mounted on analog board, close to some kind of fpga was dead.

author: Jwalling
author_rank: Unknown
timestamp: September 16, 2017, 11:42:52 am
content: There a 32KHz and a 4MHz crystal. Both are running fine. Good thing to check though.Thanks.

author: carl_lab
author_rank: Frequent Contributor
timestamp: September 17, 2017, 10:44:32 am
content: Lost "0R" (= shorted input) calibration?

author: Jwalling
author_rank: Unknown
timestamp: September 17, 2017, 11:23:39 am
content: When running the short/open corrections, the meter always thinks the leads are shorted. I'm not going to waste any more time on the thing. I'll offer it up for free for postage in the buy/sell forum.Thanks all.

author: Armadillo
author_rank: Super Contributor
timestamp: September 17, 2017, 12:25:47 pm
content: Quote from: Jwalling on September 17, 2017, 11:23:39 amLately you have been on a giving spree, oscilloscopes and now the meter, that is very nice of you, I would say...... Do you want to attached a condition to your free give away, - in the hope to update back upon successful repair for the community knowledge.

author: Jwalling
author_rank: Unknown
timestamp: September 17, 2017, 12:45:49 pm
content: If whoever takes it would like to do so, I wouldn't mind, but I won't make it a condition that they do so. I'd be curious to know what the problem is myself.

author: cape zoloh
author_rank: Contributor
timestamp: October 22, 2017, 01:41:24 pm
content: Anyone else with this problem? My meter just started to do this to me, it happened when I changed the battery I think..
Siemens 7kd2003-8ab function generator - Page 1
Forum section: electronics / repair

author: spdf
author_rank: Contributor
timestamp: October 22, 2017, 09:03:03 am
content: I couldn't locate a schematics of this unit (not even for similar older ones) what so ever and it seems that dc offset control does not work.I'll be very gratefull, if someone could share a service manual or schematics.
Digistump - Page 1
Forum section: electronics / repair

author: Seaofdep
author_rank: Regular Contributor
timestamp: October 22, 2017, 03:37:32 am
content: Hi I ordered a couple of these digistump a while back . This one I just had sitting in a dresser. Well finally had use for it and it was not working , I noticed a component was knocked off . I was wondering can I easily replace it using some board laying around an if so What exactly needs to replace it . Any help is appreciated , thank youupdate of better pic close up of boardIt is above USB first pin bellow attiny microcontrollerSent from my iPhone using Tapatalk

author: Ian.M
author_rank: Super Contributor
timestamp: October 22, 2017, 04:55:14 am
content: From pictures and schematics on the Digistump site, that's D1 on the Digispark board, which is a 3.6V Zener that clamps the USB D- signal from the ATtiny85 PB3 pin so it doesn't damage the host USB controller. Plugging it in without replacing it would be a *VERY* bad idea. Fit the replacement with the anode to ground. D2 in between the ATtiny85 and the regulator is the same type, so if you can read its markings, you can do a SMD codebook search to find the part number, or trawl through your preferred supplier's parametric search for a small 3.6V Zener with the right dimensions.

author: Seaofdep
author_rank: Regular Contributor
timestamp: October 22, 2017, 05:29:59 am
content: Quote from: Ian.M on October 22, 2017, 04:55:14 amThanks a lot . Being new to this field. Sometimes I forget to take a step back and se how simple and or easy something really is. It was a bit tricky but managed to get in close enough to see is markings thanks a lotSent from my iPhone using Tapatalk

author: Ian.M
author_rank: Super Contributor
timestamp: October 22, 2017, 05:51:17 am
content: Great. that looks up toBZT52C3V6S, available from most major distributors. Check the dimensions to confirm then put a couple on your next order.
HP Laptop TPN-C125 15-ac181no - does anyone have a schematic please? - Page 1
Forum section: electronics / repair

author: dicky96
author_rank: Regular Contributor
timestamp: October 21, 2017, 04:55:18 pm
content: Hi guysThis laptop is dead - 19V is present from the power supply but there is a dead short to ground on whichever voltage rail has +ve of electrolytic cap PC78 and Drain of PQ206Does anyone have a link for a schematic diagram please?I think the last digits of 15-ac181no just refer to this model having a norwegian keyboard and are not relevant but googling 15-ac181 isn't helping meCheersRich
Troubleshooting RF based Remote Control (Roku) - Page 1
Forum section: electronics / repair

author: cmccul002
author_rank: Newbie
timestamp: October 21, 2017, 01:47:30 am
content: Greetings all,I have a few Roku Premier boxes that have RF based remotes. Each remote pairs with its own box. I hove one remote that stopped working. I cannot get it to pair with any of the boxes. I can pair the other two remotes to any of the boxes, but none of the boxes see this one remote.Changed batteries, tried pairing to other boxes - no go. Was able to pair another remote to this box.EDIT: Actually it seems these remotes may not be RF but use WiFi instead.I took the remotes board out, and of course nothing looks odd. How would one troubleshoot an RF remote?
HP 853A, can't get it open?! - Page 1
Forum section: electronics / repair

author: aq9
author_rank: Newbie
timestamp: October 19, 2017, 02:39:34 am
content: I just got one of these, however, I am already stuck. I have the operation and "service" manual, but there does not seem to be a case opening procedure in it. It looks like I have to remove the handle first to slide the cover off, but I am unsure on how to do that, and I don't want to force it. The usual procedure of setting the handle to vertical and separating it does not work, and the handle does not seem to have a cover hiding any screws...Some help, please?

author: peter198400000
author_rank: Newbie
timestamp: October 19, 2017, 08:18:10 am
content: if u refer to the HP Spectrum Analyzer 853A?just pull to the opposite direction?to make the two fix points out their slots, and meanwhile,rotate the handle to different position,there must be one position that can have it out?

author: peter198400000
author_rank: Newbie
timestamp: October 19, 2017, 08:21:14 am
content: pardon my poor english,hope u can catch my meaning

author: aq9
author_rank: Newbie
timestamp: October 21, 2017, 12:17:30 am
content: Answering my own question; yes the handle needs to come off first. If you consult page 6/37 and 6/38 of the "Parts List", there is a exploded view of the the chassis plus handle. From this, I inferred that you need to lever off the "trim cap" over the handle ends (careful! the plastic is very brittle at this age...). Underneath, you will find 3 screws, and upon removing those (plus the cap and screws on the other side), the handle comes off. At this point, loosening the screws at the back will allow you to slide off the top/bottom cover, as you may expect.
SuperMicro PWS-920P-1R - Page 1
Forum section: electronics / repair

author: Sp4
author_rank: Contributor
timestamp: October 27, 2017, 04:23:45 pm
content: Hi AllI am trying to resuscitate "dead" power supply from SuperMicoro server. During the visual inspection located evidences of "magic smoke" and after a "quick fix" would like to test it. The problem is I can't find a way of starting it without the server itself. Does anyone have a pinout for it and what should be shorted like in regular PC switching power supplies or there is another way of starting it. Any advice is appreciated. Attaching some pics.Thanks!

author: Jwalling
author_rank: Unknown
timestamp: October 27, 2017, 04:37:38 pm
content: It looks like the fuse failed rather catastrophically. Chances are it will again, unless you replaced other blown components as well...

author: Sp4
author_rank: Contributor
timestamp: October 27, 2017, 04:41:35 pm
content: Agree, but there are no other visible damages and I was going to test it under light load first if it starts at all. The health LED indicator is still amber, but it may mean anything. Very likely I will need to continue the investigation before it switches to green.Thanks
Imax B6 clone mosfet replacement - Page 1
Forum section: electronics / repair

author: Unordung
author_rank: Contributor
timestamp: September 09, 2017, 04:35:39 am
content: Hey guys.So I had a few glasses of wine and decided to charge a lithium battery using alligator clips....A sane person would see the issue here but alas I'm clearly not that bright.Long story short I connected a 6 cell lithium battery in reverse polarity........I know its cheap, I know I can just get another and I know it's more trouble than it's worth. Alas I want to repair it.It seems to have blown the neg rail mosfet (judging by pinout).However I cant find any info on the fet nor can I read the breed as it is a little crusty.Does anyone know with certainty the part number? The genuine schematic suggests it may be a 6680 n fet.Kind regards,

author: BradC
author_rank: Super Contributor
timestamp: September 09, 2017, 04:43:48 am
content: Mine clone is currently doing a 20 hour discharge test on an SLA. If you don't get any help I'll whip the cover off tomorrow and have a look, but the clones are usually a direct copy so I'd suggest whatever is in the original schematic will do.

author: Unordung
author_rank: Contributor
timestamp: September 09, 2017, 05:13:58 am
content: Cheers mate.Yeah I was thinking it is likely a direct clone. If you can rip the top off and have a look the would be awesome.I would rather replace it with the exact same therefore limiting any other issues.Cheers

author: Armadillo
author_rank: Super Contributor
timestamp: September 09, 2017, 05:38:09 am
content: here is the useful link;https://www.eevblog.com/forum/repair/fake-imax-b6-repair/msg1133704/#msg1133704Its a N Channel Mosfethttp://www.ebay.com/itm/4pcs-Original-AO4468-4468-N-Channel-Enhancement-Mode-FET-Alpha-Omega-SOP-8-/261012270586?hash=item3cc58b2dfa:m:mI4KQW4YlRZ-vTvypNSWRWA

author: Unordung
author_rank: Contributor
timestamp: September 09, 2017, 06:38:15 am
content: Quote from: Armadillo on September 09, 2017, 05:38:09 amThank you, I did skim that thread and missed the N-chan part. I thought it was all about the P-chan.I ordered 10, hopefully that fixes it.Thanks again.

author: Unordung
author_rank: Contributor
timestamp: October 20, 2017, 08:57:36 am
content: A big thank you to Armadillo.The Fet came in today, I replaced it and the device works as per usual!Thanking you for your assistance mate!

author: Armadillo
author_rank: Super Contributor
timestamp: October 20, 2017, 10:23:16 am
content: Great thanks. Happy for you mate...
very slow fire-up from cold start on two Nakamichi CD-Player4's - Page 1
Forum section: electronics / repair

author: j ferguson
author_rank: Contributor
timestamp: October 19, 2017, 04:12:29 pm
content: I inherited my Dad's state-of-the-art HI-FI setup vintage 1989. I found the bad cap in the Nakamichi CR-3A Cassette deck - it was easy, one channel played, the other didn't but both wrote to tape. I glued the broken gear in the cassette loader back together in the TASCAM deck and now it works.At first the Nakamichi CD-Player 4 worked fine even though it hadn't run in maybe 6 or 8 years. But now, it lights up and spins the disk on cold start (after a month of disuse) but won't lock on to disk - tracking numbers don't show. So I bought another one on Ebay. It worked when I got it, but then relapsed into same problem.So I googled and googled and found a couple of other guys with same symptoms. One had discovered if he turned power on, did nothing else, and let it sit for about an hour with power on, it would then play FB. So I tried it on each machine and VOILA!I'm guessing that a voltage is either not comng up or is being pulled down by a component which gives up after an hour and lets it through.This smacks of a capacitor problem where the shakey one needs an hour to get with the program. I opened the boxes and looked at those involved in the power supply but no leaks on the electrolytics, no soot, nor other visible symptoms of distress.My plan is, with the schematic (which I have) in hand, to measure the likely voltages when one of these things is running, then do the same thing on turn-on when it's sat for a month and doesn't play. Maybe ESR meter readings at both stages.my question then, is it possible that this might be other than a capacitor?

author: Rasz
author_rank: Super Contributor
timestamp: October 19, 2017, 10:59:49 pm
content: Quote from: j ferguson on October 19, 2017, 04:12:29 pmcapacitors dont always fail visibly, especially if they arent driven hard in switching circuit. Either buy $12 ESR meter from ebay, or start hunting for bad caps on power rails with scope/swapping them one by one.might not be caps, but healing after warming up is a classic symptom.

author: j ferguson
author_rank: Contributor
timestamp: October 19, 2017, 11:57:07 pm
content: Thanks Rasz, that was pretty much my plan. the two decks are not identical even though both are labeled nakamichi cdplayer 4's. I haven't checked to see if the boards are much different.i have an ESR, which unfortunately cost more than $12, but should work just as well as the cheap ones.

author: amyk
author_rank: Super Contributor
timestamp: October 20, 2017, 01:28:14 am
content: They're 28-year-old electrolytic caps, replacing all of them would not be a bad idea.
Agilent 54621A with corrupt cal factors - Page 1
Forum section: electronics / repair

author: Sjokolade
author_rank: Regular Contributor
timestamp: October 19, 2017, 08:12:29 am
content: The coin battery on this scope is measuring 0 voltage, if I fit a new battery can I still use the scope or will the measurements be way off ?

author: Gyro
author_rank: Super Contributor
timestamp: October 19, 2017, 08:58:51 am
content: Given that it is reporting that everything is corrupt anyway, I don't think you have anything to loose.I don't know if you are able to test it's measurement accuracy at the moment but I don't think changing the battery will make it any worse than it is now.

author: Sjokolade
author_rank: Regular Contributor
timestamp: October 19, 2017, 06:23:28 pm
content: Going to replace the battery and see what happens, fan is noisy so I'm replacing that too.Thanks
Repairing an old jukebox from the 80s (with a weird problem) - Page 1
Forum section: electronics / repair

author: ollihd
author_rank: Regular Contributor
timestamp: October 19, 2017, 04:43:27 pm
content: Hi all!Im repairing an old jukebox from the 80s, 83 to be exact. The jukebox is an "NSM City II". My problem is that the jukebox "thing" that takes the record and plays it is 1. moving in the wrong direction (right opposed to left) and when it tries to play a record it spins it backwards. The same motor is controlling both, the movement and the playing of the record.First I just thought that someone had connected the motor in reverse, but that was not the case. I can't find a service manual online and am now in the situation of thinking "what should I check next".I took the board out that controls the motor (picture in link) and checked every component individually. Everything checks out.I also have a picture of the whole control system in the link.What could be causing this? It's mind boggling. Any help is greatly appreciated.Link:https://photos.app.goo.gl/FL13gt6zvcohYyYh2

author: Jeroen_Bezemer
author_rank: Contributor
timestamp: October 19, 2017, 06:42:17 pm
content: Please show a picture of the motor.If it is a single phase cage anchor motor (semi-synchronous) like used in fans and other appliances, you can reverse the movement by turning the stator upside-down.That is: disassemble the motor by removing the bearingplates. Take the coil with laminated iron and turn it around, so the thick copper loops that are on one side of the core next to the rotor get to the other side. So flip it, and don't turn, as the coil needs to stay in place, only upside-down. Then re-assemble and it will turn the other way.Verstuurd vanaf mijn SHIELD Tablet K1 met Tapatalk

author: Lorenzo_1
author_rank: Regular Contributor
timestamp: October 19, 2017, 11:58:07 pm
content: I'm no expert on such things, but I had a very similar problem some time ago with a Dual turntable which started up backwards a lot of the time. Turned out the caps in the drive motor controller had failed. Replacing them fixed it just fine and it's been working ever since. Might be worth looking at before working on the motor. It also was 1980s vintage.

author: DTJ
author_rank: Super Contributor
timestamp: October 20, 2017, 06:44:19 am
content: If its a DC motor, what controls its direction?Maybe a stuck / failed direction control relay or a failed H-bridge?
DSO-X 2002A booting problem - Page 1
Forum section: electronics / repair

author: kgmano
author_rank: Newbie
timestamp: August 17, 2017, 05:36:20 pm
content: I have a Agilent Scope Model - DSO-X 2002AWhen I turning it on, the scope does not boot up.After pressing the power switch, the following key lights on (in the same order) and stay at this position.Light up yellow Ref key arrowLight up yellow Math key arrowLight up yellow Digital key arrowLight up yellow Serial key arrowI attached a snapshot of the problem.Please give me a solution.Thanks.

author: Jurkstas
author_rank: Newbie
timestamp: October 07, 2017, 05:54:17 pm
content: Hello,I am troubleshooting a DSO-X 2012A with a similar symptomps. My patient stops at "Digital" LED. There is a "Agilent InfiniiVision 2000/3000 X-Series Oscilloscopes Service Guide". It is very basic in troubleshooting and only provides a flowchart to identify a defective unit. In my case it is the main board (who would have guessed?) and suggested solution is to replace it. No information of what is happening inside it.What I did find with this guide is that all voltages except VP23V (display backlight) are within spec. I also found that the boost IC (3064B) is disabled. It corresponds to what we see in this video:Display is back-lit later after the self-test which halts in both your and mine scopes.

author: TK
author_rank: Super Contributor
timestamp: October 07, 2017, 10:52:16 pm
content: I think it has the NAND corruption problem and it is serviced for free if you ship it to Keysight, even when it is out of warranty (contact your Keysight service center to verify).

author: rtekal
author_rank: Contributor
timestamp: October 19, 2017, 07:46:50 am
content: Keysight will repair the instrument free of cost. We had 2 nos with the same issue and out of warranty. it was repaired by Keysight free of cost.Regards
Looking for tech info on wire wound potentiometer/rheostat - Page 1
Forum section: electronics / repair

author: IconicPCB
author_rank: Super Contributor
timestamp: October 19, 2017, 12:26:01 am
content: I am sure we have all seen the old fashioned wire wound trim pots used forty year ago in so much gear around the place.These are metal shell bodies an inch in diameter , 0.4 inches tall soldered onto the PCB.I am looking mechanical information on this style of construction.I think a mob called CTS in the states used to make them ( among others?) but their website does not have references to this style any more.Any other manufacturer out there who might have information?Anybody got one of these parts who could measure it up?Any data sheets or outlets who might supply them?

author: retrolefty
author_rank: Super Contributor
timestamp: October 19, 2017, 12:58:51 am
content: Interested in following. Pics would be cool also.

author: IconicPCB
author_rank: Super Contributor
timestamp: October 19, 2017, 05:17:10 am
content: for a blurry illustration....The part in question is the pressed sheet metal trim pot in the bottom let hand quarter of the image
Repair of GW Instek GOS-630FC - Page 1
Forum section: electronics / repair

author: Rajeshpk
author_rank: Newbie
timestamp: October 18, 2017, 12:03:42 pm
content: Dear all,My Instek oscilloscope model GOS 630-FC has some problem. Its LCD display broken. Please see photo. Where from I can buy this? Kindly provide the model and details of this lcd moduleThanks and regardsRajesh PK
Please help me identify component - Page 1
Forum section: electronics / repair

author: michael.spivack.50
author_rank: Contributor
timestamp: October 17, 2017, 11:49:29 pm
content: Folks,I have a Asus chromebook c300ma system board I am working on. The lvds lcd video connector looks fried as well as the cable. Could someone help me identify the connector and where I can order it. I will probably need a cable as well. Looks similar to the 30 pin you can get for mac book air's, but I am not certain. The other thing I am looking for is perhaps a boardview and schematic donation. Want to make sure it was the cable and connection that fried it and not something else on the board with power or resistors. I'm going to attach some pictures of the connector.Thank you,Michael

author: ebclr
author_rank: Super Contributor
timestamp: October 18, 2017, 12:48:42 am
content: https://www.aliexpress.com/cheap/cheap-lvds-connectors.html

author: michael.spivack.50
author_rank: Contributor
timestamp: October 18, 2017, 10:54:54 am
content: Quote from: ebclr on October 18, 2017, 12:48:42 amSorry. Most of those look like Apple connectors which have two larger ground pins on the outside of the 30 pins on the back. I was hoping someone could get me closer to the original.Sent from my iPhone using Tapatalk
53132A counter has INTERP:FAIL (intermittent) - Page 1
Forum section: electronics / repair

author: dl1640
author_rank: Regular Contributor
timestamp: October 16, 2017, 02:08:55 am
content: on self-test or when normal run the 53132A reports INTERP:FAIL, sometimes but not always.according to the service manual the faulty ASSY will be A1 motherboard or A4 power supply.power supply is fine and i returned the unit to local Keysight service center after a few days it came with a repair quote to repalce the A1 motherboardi do not want to replace the board not economic because i rarely use this unit these years and it should not been thru over-stressed or excessive input. maybe humidity?i hope someone has same experience and knows how to put it back on the track

author: gab_au
author_rank: Contributor
timestamp: October 17, 2017, 08:29:41 am
content: Hi,a few questions first: 1) It's not clear to me from your description, does the fail occur from cold - initial turn on or after it warms up and you manually do a self test from the menu, or both?; and 2) When it fails what happens - does it not count frequency or does it not count interval or both?If it doesn't count or do interval then I'd check the +/- 7.9V rails in the trigger circuit. If it counts but doesn't do interval then I'd be looking around the ADC/DAC in the interpolation section, I don't believe they're used in the count mode. As you indicate it is intermittent then perhaps it may be a dry joint on one of those IC or maybe tin whiskers around those IC (assuming it's lead free solder). My tin whisker remedy, and general FOD mitigation, is either an esd brush, or a soft toothbrush, while using a esd wrist strap.Perhaps others more familiar with the 53132a workings may offer some different advice to get you started?

author: dl1640
author_rank: Regular Contributor
timestamp: October 18, 2017, 12:06:18 am
content: thanks for your suggestions.will try to find more when the phenomenon reoccurs, might be time consuming.

author: DaJMasta
author_rank: Super Contributor
timestamp: October 18, 2017, 03:53:35 am
content: These sort of intermittent failures certainly can be, basically, you want to find a way where you can replicate the failure so you can actually start measuring things and trying to find the cause. Rather than just having your scope probing things every time you power it up, I'd open it up and start wiggling cables and such - mechanical failures are a pretty common intermittent failure, so a cold solder joint, an oxidized connector, or a damaged cable can sometimes be the culprit - which while it's hard to find, it's often an easy fix.Good luck!
Old vacuum tube scopes "What Can Old Test Gear Teach Us About Electronics?" - Page 1
Forum section: electronics / repair

author: lordvader88
author_rank: Frequent Contributor
timestamp: October 14, 2017, 06:09:25 pm
content: I also just got 1 of these old 1960's RCA WO33A tube scopes. However mine's been dropped or thrown badly ? (I wonder if anyone was killed???) The board is broke right in half and the CRT has some ceramic inside broke off. Very nice clean layout, sure hope the CRT still works when I fix the rest of it.However Mr. Carlson got 2 of these easy, and they work. Here's a good detailed video on them and in-depth on tubes circuits etc

author: bitseeker
author_rank: Super Contributor
timestamp: October 15, 2017, 07:30:54 am
content: Yeah, it was neat seeing inside those. Hope you get yours working, too.

author: vk6zgo
author_rank: Super Contributor
timestamp: October 18, 2017, 03:41:22 am
content: Those little RCAs were rare as hen's teeth in Oz.AWA had a tie up with RCA, so some of the AWA 'scopes may have been licence -built versions of their units but again, I only ever saw big ones with 5inch screens.The old Perth Tech School had some Cossors with similar performance in their labs, & there were quite a few Heathkits around back in the late 1950s/early 1960s.There were some Philips ones with similar specs, too.They were really already Dinosaurs, as Telequipment had the "Serviscope" available in a similar sized package.The Serviscope had 5MHz bandwidth, proper triggering, & coax inputs (albeit SO239s) in a similar sized package.It was quite a bit more expensive,which if you only needed a 'scope for audio use probably put it out of consideration.
Old Weller 8200 She lives- corroded AC plug  - Page 1
Forum section: electronics / repair

author: lordvader88
author_rank: Frequent Contributor
timestamp: October 07, 2017, 07:48:27 am
content: Before sanding off the 2 AC prongs, I was getting 10^5-6 Ohm on this primary trans. winding. After it went to a few ohms IDR but yup the only reason this 140W Weller didn't work was corroded AC plugJust put her to good use on some brass AC connectors and 12G wire

author: lordvader88
author_rank: Frequent Contributor
timestamp: October 07, 2017, 08:08:22 am
content: Its like having a Negh'Var Class Crursier, but from Star Wars

author: floobydust
author_rank: Super Contributor
timestamp: October 16, 2017, 02:21:57 am
content: Just a note- the ol' Weller 8200generates several kV at the tipwhen switching the gun on/off or hi/low.Kills a lot of semiconductors, like a massive ESD hit.Trick is only have the heat on or off when touching (soldering) the parts. Or ground the tip (secondary).I wonder if people know to re-torque the tip nuts fairly frequently to give good connections, or the thing never heats up.

author: gibbled
author_rank: Regular Contributor
timestamp: October 17, 2017, 07:11:11 pm
content: Glad to hear!I bought mine before I was a teenager. mostly used for demagnetizing tools these days...
manual for power designs 3K10 high voltage power supply  - Page 1
Forum section: electronics / repair

author: crazyhog
author_rank: Regular Contributor
timestamp: August 19, 2017, 08:16:43 am
content: Hi all,I got a broken Power Designs 3K10 high voltage power supply (3kv, 10ma) off ebay. Unfortunately I couldn't find the schematic for it. Does anyone have the service manual or the schematic for this device?Please note I've found the manual for 3K10B but it's not the same.Thanks

author: bitseeker
author_rank: Super Contributor
timestamp: August 19, 2017, 08:48:07 am
content: I don't recall seeing any online. If no one has a paper manual, you might try posting high-res photos of your 3K10 to see if anyone versed in HV supplies can offer some insights.

author: Vertigo_01
author_rank: Newbie
timestamp: October 17, 2017, 07:58:40 am
content: I was digging for something similar and found this document in a couple of places. One repository referred to it as a "Operator manual", which it indeed is, but scrolled down to the 4th-or-5th-from-last pages will find you a complete schematic of the device, including parts lists, detailed specifications, etc.I honestly can't imagine you'd need *MORE* detail than this document provides?http://vwww.ko4bb.com/manuals/142.22.179.130/Power_Designs_3K10B_High_Voltage_Power_Supply_Service_Manual-Power_Designs_3K10B.pdfHopefully helpful?

author: bitseeker
author_rank: Super Contributor
timestamp: October 17, 2017, 08:04:59 am
content: Nice find. I didn't see that one on KO4BB back in August.