hybridfree/eevblog-posts huggingface dataset:
Repairing BT speaker that won’t power or charge - Page 1
Forum section: electronics / repair

author: DaveInPA
author_rank: Newbie
timestamp: May 07, 2024, 01:11:13 am
content: I’ve got a JBL charge 4 which is a Bluetooth speaker with a rechargeable battery and powered by usb-c. Been working great for many years and I usually just leave it plugged in all the time. This morning when I turn it on it powers up and then a few seconds later powers down. So I can’t help myself and have to fix this thing instead of buying a new one.The battery says it’s rated for 3.7v and it’s reading 3.2v. I kept it unplugged from usb port and removed battery and hooked up a DC supply with 3.7v and it works just fine. I wanted to update the firmware as some on the internet said that could be the issue. However the app that connects to it sees it’s not plugged into the usb power and won’t let me.Then I remove the small board that has the usb-c power in and also happens to have a usb-a power out to charge other devices. I confirmed that plugged in I’m getting 5v on one of the pins. I’m also getting higher voltages on other pins but not sure what that tells me. On the main board I see a chip for usb charging port controller and another chip for lithium ion usb charging.So here’s my question. The device doesn’t work when plugged in with or without the battery attached. Does that mean the usb-c terminal is bad or something else went bad in the power circuit? Or do these devices have some sort of reason to require a working battery to be connected in order for it to power up?I’ve got 12v li-ion chargers but no idea how t9 charge a 3.7v battery. If I could that would probably be my next step…

author: KhronX
author_rank: Frequent Contributor
timestamp: May 07, 2024, 05:42:10 am
content: Quote from: DaveInPA on May 07, 2024, 01:11:13 amWell, if you have a DC supply that can put out 3.7v (hopefully current-limited?), then you should be able to charge the battery itself.Measure / confirm which terminal is which, on the battery, before continuing!Hook up the supply to the battery (+ to +, - to -), set it to4v,current limit it to 0.5-1A, and turn it on. The voltage will jump up a bit, from the 3.2v you initially measured, but should bump against the ceiling set by the current limit. Let it be for a while, keeping an eye on the voltage & current. Once it's up to at least 3.6-3.7v, turn off the "charger", reconnect the battery to the speaker's circuitry and see if it helped any.
repairing burned PCBs on miller welder? - Page 1
Forum section: electronics / repair

author: coppercone2
author_rank: Super Contributor
timestamp: October 01, 2021, 02:15:04 pm
content: So my miller welder has got a little bit of life back in it with front panel controls being unlocked but there is still two little transistors that keep blowing up, one of them is near a patch of burn damage that I thought was OK but maybe since its some inverter control stuff, its enough of a problem that its doing something I can't measure with a DMM on the repair bench, so I decided to mill & glue the area. There is also a out of spec resistor on another PCB that I need to deal with. After I do the repair I will replace like 20 little transistors (8x bjt and 12x nmos), that possibly are damaged. Well, the whole carbonization mechanical PCB repair might be unncecessary, because the fact is the PCB was damaged, I repaired it, then the IGBT blew up and re-damaged the board, and I only replaced 2 obviously damaged parts on the board that came up as short with DMM check, so its entirely possible that there are adjacent damaged components causing the fault, not the carbon, but to preserve my sanity I decided to do a full repair on the PCB after I remove the suspicious parts this time prior to putting on new parts because its alot of work to desolder 4 terminal DIP transistors!PlanMy plan was to use a small endmill (1/8 ball) to get rid of all the remaining carbonization (I got what I could off the top, then to pour in DP270 potting compound into the hole, possibly with tape on the bottom if there is a hole.I am wondering if I should add fiberglass dust to the epoxy? I have a container of it, I believe its for stiffening parts, and I never filled a strait up hole in a PCB before. It also needs conformal coating afterwards, so the patch should be well compatible with the conformal coating, I thought fiberglass addition to the epoxy would help with the adhesion of the conformal coat and stiffen it further. Afterwards I would polish with a unionized abrasive (rubber abrasive).****I also thought maybe to get glass spheres or something to strengthen the epoxy, instead of just fiberglass dust.. I see these types of fillers for sale, not sure what the best one is.I also need a way to clean the old conformal coating off the PCB, I used a pace 'hot scraper' attachment for a pulse heater to get rid of it prior to the first rework, but I ended up replacing many parts, so afterwards my flux cleaner (flux off) ended up destroying the rest of the conformal coating so its really shitty now. I would just use more flux-off but its like 25$ a can and it is really wasteful to remove the delapitated damaged conformal coating. I figured name brand flux remover would be conformal coating safeThen, if it works, and the thermal camera does not show any more fires, I will test it with actual welding then apply conformal coat to the reworked functional PCB, probobly from MG chemicals spray.I also noticed another patch on the PCB where there is a dark mark, but it looks like only the conformal coating has darkened or turned amber.. does anyone know if this is a problem?
Repairing CompactLogix 1769-xxx Modules - Page 1
Forum section: electronics / repair

author: lcardoso.2709
author_rank: Newbie
timestamp: March 25, 2023, 10:25:18 am
content: Does anyone have datasheets of the D151811-2910 and D151811-3210 ICs found in some CompactLogix 1769-xxx line modules ?I have some 1769-OB32 and IF8 modules on the bench for repair and they are not communicating with the PLC (It is not found by RSLinx in the rack).Any tips for repair resolution will be welcome.Thanks,Luciano
Repairing Dacmagic+ - Page 1
Forum section: electronics / repair

author: onurz
author_rank: Newbie
timestamp: May 10, 2020, 11:52:41 pm
content: I've been using dacmagic plus for about 4 years, however I bought it used so I don't know how old is it. Since last 3-4 weeks it does'nt work properly. When I turn it on and when there is a input signal, it only produces a noise. When it happened for the first time I let it on for 15 minutes and selected an empty input, then I selected my usb input again and turned it off and on. It started to work properly. But when I turn it off again it made the same thing. Now waiting 15 minutes or even longer such as 24 hours doesn't work, it only produces high pitch noise. I tried different inputs as well, usb-PC, optical-PS4, Bluetooth-Phone but the result was same.They suggested on diyaudio (link) to replace some caps. So I did try to change them. While doing that I've lost some pads but managed scrape some paint and solder the cap. If you watch the video you'll see that while booting up, dacmagic cycles the input leds. Right now when I turn it on dacmagic stucks on the input leds cycling. Does anyone have any idea what the problem is?
Repairing fine pcb traces - Page 1
Forum section: electronics / repair

author: Sanxion
author_rank: Contributor
timestamp: May 25, 2023, 12:52:06 pm
content: Hi all,I would like to ask if it possible to repair very fine pcb traces that have become corroded. I have an old computer board that has suffered from a battery leak. Please have a look at the image and let me know if it possible and if so, how.Thanks.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 25, 2023, 01:02:06 pm
content: i take in a multibraid cable one of the small wire in them, you can choose the core wire size ... or wire wrap etc .....scrape the pcb varnish on each pcb trace and carefully redo them but dont overheat, they could lift from the pcbit will be a long process if you are able to do itBut the way i see it you have corrosion in the white plug .... many places have been damaged, not sure i would do this amount of workyou can or could find another pcb ?? unless it is a special board ?and in the end you may still get some failures over time ......

author: wasedadoc
author_rank: Super Contributor
timestamp: May 25, 2023, 01:19:29 pm
content: Top left corner doesn't look good too!

author: Haenk
author_rank: Super Contributor
timestamp: May 25, 2023, 02:43:42 pm
content: I'd say don't waste your time, unless it's some super-rare board that is of historical importance and irreplaceable.There has been so much corrosion done to the board that you would need to replace every single trace and most parts - and you can only see the damages on the top layer. The further down layers are likely damaged in the same way and are unreachable.Unfortunately, the corrosion will never stop and will worsen over time, so a "good" trace might be eaten away in a year or two or three. Essentially a ticking time bomb.

author: Sanxion
author_rank: Contributor
timestamp: May 25, 2023, 04:01:50 pm
content: I knew it was bad but thought I would give it a try...I did actually fix a few traces and restored some functionality but it probably is too far damaged. Thanks for all the responses!
Repairing IPG Photonics YRL-4000 Fiber Laser  - Page 1
Forum section: electronics / repair

author: BiD
author_rank: Contributor
timestamp: October 15, 2020, 05:27:10 am
content: Hello!I am slowly working towards repairing a IPG Photonics Fiber Laser unit I had picked up for fairly cheap, its a 4000W unit. Currently I am working to repair a severed fiber that's between a "coupler" unit and an optical switch. I have access to a fusion splicer however I wanted to figure out what type of fiber optic I'm dealing with.The cable.jpeg is what the cable looks like up close, it's terminated by a bayonet-type connector as seen in connector, that connector goes into the input of the optical switch. The other end, the metal jacket with the yellow plastic terminates within the rack housing and the inner whiteish jacket continues onto a "coupler". As far as I can tell all the fiber optic are fused-spliced, I assume this is due to minimize loss and not burnt fiber. The severed fiber optic is between where metal jacket terminates and the coupler unit.. Measurement with the coating on is ~ 213um (coating.jpeg) and the cladding is 123um (cladding.jpeg). I assume that this is a 125 um fiber optic based on the 123um measurement in cladding.jpeg.I took the fiber optic and tried to put the cleaved end to be as parallel as possible to the microscope lens and shine incident light on the opposite end of the fiber to get the photo seen in core.jpg. Based on the approximate pixel ratio of the cladding to the core diameter: 1271px/1598px, I computed the core to be: 125um * 1271/1598 = 99.4um ~ 100um.This tells me that it's a 125um/100um fiber optic however this seems like an unusual size for a fiber optic.* Could someone shed some light on this?* Am I measuring something incorrectly?* Does anyone know why the fiber optic and the two copper interlock are free floating in the plastic tube instead of the fiber optic having it's own jacket like telecom fiber optic?
Repairing laptop; need advice on tactile switch manufacturer to go with. - Page 1
Forum section: electronics / repair

author: ballsystemlord
author_rank: Frequent Contributor
timestamp: November 17, 2024, 03:34:23 am
content: Hello,I have an older laptop who's only problem is that the mouse button switch failed. I've not yet opened the laptop up, but it feels like it's a basic 4p dip switch which you see used everywhere. Because it's a mouse switch, it's going to take a lot of abuse. So, I decided to look for something with more endurance. I'm now browsing mouser and I see for the highest endurance switches I can choose between the following manufacturers:C&K SwitchesE-SwitchOmronAlps AlpineApemIDK which of these would be considered the best. I'm also uncertain if there's a particular switch design which, though different, I might bodge in to get a more permanent solution.Anyone got advice?Thanks!

author: ballsystemlord
author_rank: Frequent Contributor
timestamp: November 21, 2024, 12:06:35 am
content: I opened it up. The buttons look like half height SMD ones. Other than that, it's exactly what I expected.

author: amyk
author_rank: Super Contributor
timestamp: November 21, 2024, 04:59:26 am
content: I've had success with opening those switches up and polishing the contacts with cleaner.If you really want to replace it, Alps and Omron are safe choices.
Repairing LeCroy 9400A, possible memory error - Page 1
Forum section: electronics / repair

author: kubark42
author_rank: Contributor
timestamp: April 09, 2022, 08:28:11 pm
content: I have a LeCroy 9400A which has problems with the first channel. It seems to read data okay, but there are these weird marching lines.https://imgur.com/a/V5wEOLkThey seem to be the same height as the observed data, which makes me think that this is some kind of display or memory issue.Anyone seen something like this? Thoughts for where to start?
Repairing LED Driver for LEDLite 50w 5Ft RTWPLED5 WL50-23-001 - Page 1
Forum section: electronics / repair

author: nick@daviesclan.f9.co.uk
author_rank: Newbie
timestamp: November 17, 2021, 04:34:52 pm
content: I had a problem with an 5ft LEDLite light from TLC that worked initially, then flashed randomly before not working. Another guy on the forum had the same problem but could not find a solution.I hate landfill so decided to attempt a fix. On mine the issue was the transformer. A chip was loose on the LED Driver so I attempted to re-solder it. Initially this worked but came loose again upon refitting into the light casing. The second attempt ended up shorting the driver.Having contacted the supplier (who does not supply spare parts), I gleaned the following information:Maker CiguangModel: WL50-23-001Input Voltage 220-240V/50Hz/60HzInput power 50W maxInput Current: 0.24A maxPF:>0.9. TC:<75 degrees C, Ta:-15 degrees C - +50 degrees CSec Output: 68VOutput Current 730mAConstant current driverThe closest I could find on the web after extensive searching was:HuaTec EagleriseModel LS-50-700 LI1Input Voltage 220-240V/50Hz/60HzInput power 50.1W maxInput Current: 0.37A maxPF:>0.95. Ta:45 degrees C, TC:85 degrees CSec Output: 42.5-71.5VDCOutput Current 700mAConstant current driverThis is available on Amazon.co.uk £17.99 at the time of writing.It just fits in the case although you can't secure it using the same holes as the orginal due to its different shape. Not an issue as the light remains static on the ceiling once fitted.So I fitted the LED Driver and its fixed.So much more satisfying creating more landfill.I hope this helps someone else with the same problems.P.S. The supplier was helpful in confirming the spec on the chinese made LED Driver. They can be reached at info@LEDlite.co.uk
Repairing Mark Ethan 898D Hot Air Station - Page 1
Forum section: electronics / repair

author: matomback
author_rank: Newbie
timestamp: July 03, 2019, 10:42:17 pm
content: I have a 898D clone (Mark Ethan) that I have been using for a while but did not purchase originally.Recently I turned the hot air on and found the temp reading would not rise above 008. The fan starts and is fully controllable, but the heater appears to be broken. I purchased a replacement heating element for ~ $5 and installed it into the handle. It did not change the functionality so it seems that it is not the issue. Is there something else inside the base unit that I can look at / possibly replace to fix? I can't seem to find much information about this model, no schematic or anything else that would help me recognize what I might be looking for. However I did notice that the two 'hot' leads of the handle heating element (one red and one black) are at the same voltage and connected according to connectivity test when the unit is attempting to heat up.Any help would be greatly appreciated, thanks!

author: LateLesley
author_rank: Frequent Contributor
timestamp: July 05, 2019, 06:50:31 am
content: I have a Saike 898D, basically a re-badge of the same model. My hot air gun died one day, fan would work intermittently, but in my case the heater and fan was ok. The cheap cable on the device was a fault. Broken cable. I replaced the cable with some 12 core I had on a reel, and got some new connectors to crimp on for plugging in inside the device.So, First, I would buzz out the cable, before condemning the electronics.
Repairing mp3 player - Page 1
Forum section: electronics / repair

author: nForce
author_rank: Frequent Contributor
timestamp: July 14, 2019, 05:04:30 pm
content: Hello,I have a cheap ebay mp3 player:https://www.ebay.com/itm/New-Portable-Music-MP3-Player-USB-Digital-LCD-Screen-Support-32GB-TF-FM-Radio/152058961872?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D57921%26meid%3Daf740338840d4ed59e454a15efa04b23%26pid%3D100005%26rk%3D11%26rkt%3D12%26mehot%3Dpp%26sd%3D223278297642%26itm%3D152058961872%26pg%3D2047675&_trksid=p2047675.c100005.m1851I copied a few times .mp3 files on the sd card throuqh usb. It worked fine. But today I have turn it on, and selected music and I got error "No file!". When I plug it into the computer I see that there are files on the micro SD card. I have tried several times to format using different file systems, like FAT, FAT32 and NTFS and I get the same error.Because I love electronics, I will try to fix it. Does anyone have any idea what is wrong?Thanks.
Repairing old amplifier, trying to source alternative transistors/Mosfets. - Page 1
Forum section: electronics / repair

author: Alfizzle
author_rank: Newbie
timestamp: September 19, 2014, 02:44:18 pm
content: HiThis is my first post here, i watched Dave's videos on YouTube for quite some time but haven't signed up here till now!Im repairing an old amplifier of 90's vintage, it currently has two toshiba k1529 and two toshiba j200.I have been looking for suitable replacements, as the originals seem pretty expensive (this old amp im repairing is only a cheapy)Could someone kindly inform me of a cheaper alternative to the two mentioned parts above?Im not an expert, but im pretty competent at repairing items by replacing faulty parts with the same original model part's (in this case it will be false economy to do that).Apologies if my format/way i have asked my question is incorrect. please tell me if i need to make any changes to it or add any more information.Thank you.

author: ignator
author_rank: Regular Contributor
timestamp: September 19, 2014, 04:13:27 pm
content: When I searched for "K1529" I found a application note (national semiconductor ap note 1645) for LM4702. This is an audio driver IC that called out this transistor and it's complimentary J200. It has a table that I snapshot below showing other transistors they tested for compatibility. Look up the international rectifier components data sheet and compare to your parts data sheets. My quick look found the IRFP240 was the same package size and pinout as the 2SK1529. And better voltage and current capability.Device Pair Manufacturer2SK1057 / 2SJ161 Renesas2SK1058 / 2SJ162 RenesasBUZ900 / BUZ905 MagnatecBUZ901 / BUZ906 Magnatec2SK1529 / 2SJ200 Toshiba2SK1530 / 2SJ201 ToshibaIRFP240 / IRFP9240 International Rectifier

author: Alfizzle
author_rank: Newbie
timestamp: September 20, 2014, 05:51:17 am
content: Thanks for your reply, ill look into that now.

author: keland_uk
author_rank: Contributor
timestamp: August 01, 2021, 10:59:45 pm
content: I know this is an old thread, but did you or anyone else have modern drop in replacements for J200/K1529 and similar replacements?The list in this thread look like contenders. Just wondering if any sucesses?cct diagram of a sony amplifier from late 90's that use them attachedMaybe someone could point to what things may need changing in the circuitary to support some of the other MOSFETS identified? (the IRFP240 / IRFP9240 seem to still being manufactured)or any other MOSFETS.Any pointers appreciated

author: David Hess
author_rank: Super Contributor
timestamp: August 02, 2021, 01:28:45 am
content: Starting with p-channel MOSFETs led me to the IRFP9240/IRF240 as the best match and place to start because of slightly lower threshold voltage than the alternatives. The circuit may need to be adjusted for the higher combined threshold voltage.
Repairing old BK 3010 and 3011 function generator, odd noise - Page 1
Forum section: electronics / repair

author: JTM45
author_rank: Newbie
timestamp: March 25, 2021, 02:02:12 am
content: New to electronic work, built/copied a few tube amps, now trying my hand at more in-depth stuff that will make me learn more.I needed a function generator, so I have acquired a few. I got one Heath 1274 that seem to work fine, so that’s for my guitar amp work, but I did get two old BK Precisions, a 3010 that is from the late 70s, and a 3011 from the 80s. I know it’s worth nothing value wise, but it works enough it’s of potentially great value to me as something to learn on.Both have a sine wave that has a noise at both peaks of the cycle. (See image)So know very little about the functions other than I understand the triangle wave is being used to make the sine wave.I have the PDF manuals to calibrate both, and the schematics with part lists for both.Any idea what this is? Or where to start testing for proper functions?I should add, I have acquired an oscilloscope. Sig 1202x-e

author: mawyatt
author_rank: Super Contributor
timestamp: March 25, 2021, 01:33:43 pm
content: Recall these old Function Generators utilized a sine wave approximation technique where a triangle wave was passed thru a network of diodes (or transistors) and resistors in an attenuator. This attenuator would vary the attenuation amount based upon the triangle wave input level, thus approximating a sinusoidal result at the output. Intersil and Xar made function generator chips that also used this technique.The noise blimp on the sine wave is just the peak of the triangle wave coupling thru the diode R attenuator.Best,
Repairing old Fluke's  - Page 1
Forum section: electronics / repair

author: IvanB303
author_rank: Newbie
timestamp: March 25, 2025, 12:33:18 pm
content: G'dayFirst post here! So I've been a fairly successful synth tech in Sydney for a couple of years now on the side. The downside is that other than looking for old cheap broken musical electronics, I'm finding myself into test gear as well now.....save meI like the Series 2 Flukes not sure why, think I saw them in my past engineering/lab life. I got a 77 a while ago which all works but the switch is a bit rough. What do I do about this other than contact cleaner inside?Then I just got a 79 for $65 and and it's almost pristine the case but, inside the screw posts are broken it seems and someone tried to sort it with some sort of cement. The last digit on the LCD through is flaky on some of the segments. What you guys reckon fixable?I now have 6 multimeters.....

author: tunk
author_rank: Super Contributor
timestamp: March 25, 2025, 12:39:47 pm
content: The LCD flakiness could be the zebra strip.You could try to clean it with isopropanol;both sides of the strip, the PCB and LCD.

author: IvanB303
author_rank: Newbie
timestamp: March 26, 2025, 11:54:03 am
content: Well its'a bit of a horror show inside, someone i think overtightened the screws and broke most of the screw posts inside doh! Damn does it look great from the other side. I willl see if i can clean that zebra strip, seems to be a pretty common one. Thanks for that
Repairing old Heathkit GC-1000 Most Accurate Clock - Page 1
Forum section: electronics / repair

author: joeqsmith
author_rank: Super Contributor
timestamp: October 05, 2024, 02:12:59 am
content: This clock was given to me in non-working order. It was released in 1983 and assembled by the original owners father. A quick check, there was a bad 60Hz hum. When I pulled the main filter cap, one lead fell out. Suspect it corroded. I checked some of the other alum. elecs. and a few had high ESR or very low capacitance. One 22uF read 2uF. I didn't find anything else wrong with it and went ahead and realigned it. It's been running now in this current state for a few days and maintaining a lock.Pretty cool bit of history.

author: floobydust
author_rank: Super Contributor
timestamp: October 05, 2024, 03:45:52 am
content: That's really nice, a lot of advanced engineering for the time. Dec. 1983 $250 kit price is $790 in today's dollars. That was a big purchase.It seems to have a Mostek 3870 MCU driving a DAC controlling a varactor diode (VCO) on a 3.6MHz ref. oscillator. Like an early GPSDO but WWV instead. I wonder if anyone else did this back then? On an odd ball MCU with just an accumulator, also doing the LED mux. Pretty good for a few KB."Propagation delay can be set for up to 18.75 milliseconds (3600 miles from WWV in Ft. collins, Colorado)."A History of Early Microcontrollers, Part 6: The Fairchild F8 and Mostek MK3870TEST pin can be exploited to read out the firmwarehttps://hackaday.com/tag/mk3870/

author: Haenk
author_rank: Super Contributor
timestamp: October 05, 2024, 10:49:28 am
content: I'd like to mentionhttps://www.mikrocontroller.net/attachment/108482/Elektor_10_1980g.PDFThat's 1980, and an even more proper "most accurate" clock

author: joeqsmith
author_rank: Super Contributor
timestamp: October 05, 2024, 01:11:15 pm
content: Notice in this video that the bottom of the unit has various decals. Also notice the test board is completely different. It looks like someone had swapped in a SMP in place of the linear regulator on theirs as well. You can see the damage to the PCB on mine from the heat. Because their father had worked for Heathkit, it is very possible this was one of the pre-released units. This is how I ended up with the service manual.A site where there are swapping in a SMP.https://www.thomasnixie.com/thomas-nixie-history/heath-kit-gc-1000-most-accurate-clockA video where they are swapping in a SMP.Manual for ithttps://www.scribd.com/document/695099016/Heathkit-GC-1000-H-ManualAnother decent site for one. Similar, I realigned the tone decoders and the receiver but made no other changes to it beyond cleaning up some of the old flux. The goal was to leave it as original as possible.https://www.smbaker.com/heathkit-gc-1000-most-accurate-enigma
Repairing philips lumea ipl model sc2006 hair removal ipl - Page 1
Forum section: electronics / repair

author: Saleem
author_rank: Newbie
timestamp: February 07, 2025, 06:39:58 pm
content: I need circuit diagram for philips lumea ipl sc2006 model

author: Gyro
author_rank: Super Contributor
timestamp: February 07, 2025, 07:14:51 pm
content: Welcome to the forum,Please exercise some patience. 3 posts asking for the same thing in the space of 20 minutes will get you banned! If somebody can help, they will respond to your first post.

author: thm_w
author_rank: Super Contributor
timestamp: February 08, 2025, 12:09:34 am
content: What is the failure symptom?- Device does not power on at all- Device powers on but does not flash lampetc.
Repairing plastic threads & discoloration - Page 1
Forum section: electronics / repair

author: blacksheeplogic
author_rank: Frequent Contributor
timestamp: August 25, 2022, 07:56:33 pm
content: Just wondering how others are making repairs to plastic cases.Where the thread is too small and fine for an insert I've been using PTFE tape to create more of a bite (where it's not broken). Helps and is better than moving up in size. Any better ideas, glue I found is pretty messy for a lot of these which are very small.I have a lot of Atari 8-bit gear, some I have re-cased, but I need to start using what I have. Hydrogen Peroxide can work in the short term but it's not good for the plastic nor is it perfect. Considering spray painting the cases now but it's never a 100% color match and I want to keep these as collectible. I'm looking at some point to downsize and maybe only keep one of my systems so collect-ability is important. I have considered selling some working systems off as parts but I'm not at the point of wanting to trash working systems.
Repairing r9 290 HDMI/DVI output  DP is working - Page 1
Forum section: electronics / repair

author: kirils
author_rank: Newbie
timestamp: September 01, 2021, 02:02:07 am
content: Hi, i got r9 290 tri-x (from what is see it is reference board) for cheap. The problem is that only DP is working DVI and HDMI doesn`t have any output. The seller say that the problem occurred when he plug a monitor in the card. The monitor was powered directly from the wall but the computer trought cheap ups. There where sparks from the shield of the hdmi so i thing thing the ups was not grounded. So from where i can start the troubleshooting?I attach schematics of non reference version of the board but at least looks the same in the part of interest.[ Specified attachment is not available ]BoardViewer.zip

author: testpoint1
author_rank: Frequent Contributor
timestamp: September 02, 2021, 04:09:42 am
content: I never repair any AMD card, but according my Nvidia experience, you can use a IR camera to check which interface chip is broken.
Repairing Samsung plasma TV PN64D550 - Page 1
Forum section: electronics / repair

author: pap
author_rank: Newbie
timestamp: July 19, 2021, 02:20:32 am
content: Hi all!First post and fairly new at fixing electronics, so all pointers will be appreciated!I recently picked up a huge Samsung plasma TV (Model PN64D550) for free as, according to the previous owner, it was no longer working. I am trying to repair it but the information I found so far hasn't been able to help me narrow down the failure point on this specific unit.very useful to diagnose power supply issues around the FETs, but it doesn't seem to be the issue for my unitvery similar issue. same power supply board model number (#BN44-00445A)Here's what I'm experiencing with this TV: When the TV is plugged in, there are 2 clicks (relays) from the power supply board, and the standby light blinks 6 times, then turns off. I can then press the power button, and the standby light momentarily blinks once, but nothing happens. Same behavior when I press a button on the remote: the standby LED blinks a few times, but the TV does not do anything else. I also connected the LAN port of the back of the TV to an ethernet hub, and the LED on the hub is solid green, indicating that the main board in the TV is likely working. I also noticed that after 5 minutes, the unit apparently reboots: the standby LED blinks another 6 times, and the cycle seems to repeat over and over. Otherwise, the TV is not displaying any activity: no sound, no flashes on the screen, nothing else.I took down the back cover and started looking for issues. All caps seem to be in good condition. The label in the back of the TV indicates that Vs should be 217V and Va to be 91V. I suspect however that this voltage is only provided to the sub-boards when power is actually turned on, so at the moment, the TP Vs and Va don't show anything. On the power supply board, the label for the connector to the T-CON board indicates that 5.3v should be present on pins 5 and 6 of the connector. My multimeter agrees with this. Voltage on the main board connector also appears correct (15V and 6.2V). The 3rd connector on the power supply board feeds the Y and X assemblies, and again, this does not show any voltage at all at this point.I also see a green flashing LED on the T CON board (slow blinking, approx every 2 seconds). This seems to confirm that the voltage provided to that board is fine also.I visually inspected the other boards, and could not notice anything unusual (no burnt components, flaky joints, etc).I unplugged the Y MODULE power supply cable, and the issue remains the same (standby led blinking, but won't power on).My questions:Should I be able to read a value for Vs and Va even if the unit is on standby?Would it make sense to try to bypass standby mode using a small resistor like herehttps://youtu.be/dswtNRiZwN8?t=798to determine if Vs is within specs?What else can I try to further diagnose this?Thanks for your help and input!
Repairing some IFR/Marconi rf signal generators (2030,2031,2040,2052) - Page 1
Forum section: electronics / repair

author: cio74
author_rank: Regular Contributor
timestamp: May 22, 2023, 12:49:58 pm
content: Hello,I have recently bought 4 old, not (exactly) working, RF signal generators, now trying to see what can be fixed.The 2030 and 2040 were displaying "Cannot set-up link between processors"The 2031 display was broken, nothing being showed upThe 2052 was displaying "Calibration date expired" and "Incorrect software fitted"All units have some sort of add on boards, options, that I believe can be fitted from one device to the other.Sadly, the display on 2052 arrived with the bottom half of LCD not displaying anything good.I took the display from the 2030 and replaxced the one from 2031, the unit starts up displaying an error about real time clock. Then it works just fine, not displaying any other errors. I have not checked output level, modulation, etc, just doing simple power on tests.After taking the cables out of the 2040 and put them back in, the cannot setup link error has just dissapeared and the device boots up without showing any error. However, if left running for some minutes it starts to throw some errors that I shall post later on.I then took the LCD from 2040 and replaced the one in 2052. It starts up displaying the same incorrect software fitted and calibration expired but it then goes on and seems to work. Again, have not checked output levels or anyting appart from powering up and some menu inputs.Another issues with 2052, it came without the RF output module which seems to be an relay based attenuator ending up with a RF plug. However, the 2030 have one so I just took it out and looking to retrofit the 2052. But when trying to module in, there is something not connected on the 2052 metallic box, one connector was atatched as seen in picture and then it is another one unconnected.Perhaps someone own such unit or/and know what could possible be connected there or/and best the service manual for the 2052?Thanks.Cio
Repairing SPS for LED lighting - Page 1
Forum section: electronics / repair

author: Richard Sendall
author_rank: Newbie
timestamp: August 21, 2020, 08:21:33 am
content: Hello all, would appreciate some help repairing a power supply for LED lighting.I have a number of LED strip lights from the company LEDLight. The power supply has become defective, the symptoms being that the LEDs flash on/off approximately 2/3 times per second and there is a ticking noise from the power supply. I have checked and confirmed that the actual LEDs themselves work correctly by connecting them to a known good power supply. The power supply module specification is:Manufacturer: CiguanModel: WL50-23-001Input: 230v, 215mAOutput: 66v DC, 660mAI have had no luck in finding any information on the company Ciguan or the model WL50-23-001 and LEDLight do not stock/supply spares. I have attempted to perform some limited testing and diagnostics on the power supply, it appears to be a simple buck converter with a chopper circuit. I have replaced all electrolytic capacitors with new ones and have also replaced the output inductors, diode and switching transistor (SVF12N60F) with known good parts from a working power supply. I have also checked the output of the bridge rectifier across the mains input, I measure the expected 340v (240v x root 2), so it looks like the chopper circuit/controller IC has a fault. Unfortunately, these components are all surface mount and there's no marking on the IC which is a 6-pin device.Any ideas on what I could do next? Whilst the LED lamps aren't very expensive, would be nice to fix it rather than bin it.Many thanks!
Repairing the contacts on a multimeter rotary selector by heating - old trick? - Page 1
Forum section: electronics / repair

author: vl_garistov
author_rank: Newbie
timestamp: August 14, 2020, 01:05:25 am
content: I had a problem on my Mastech MS8264 - the rotary selector wasn't making good contact when set to continuity mode. Cleaning the contacts didn't help. Fiddling with the selector and pushing hard on it temporarily improved things so I decided to put a tiny bit of solder on the suspected contacts. The idea was to make them push harder against the multimeter PCB.But when I touched the contacts with the soldering iron they bent from the heat! They sort of popped out a little and now the meter works much better.I discovered this on accident but it sure sounds like an old trick - if the rotary selector contacts are causing problems, just heat them a little until they bend.My question is have you done or heard of this? Did I reinvent an old trick or came up with a new one? Probably the former, but who knows...

author: bob91343
author_rank: Super Contributor
timestamp: August 14, 2020, 02:48:48 am
content: I was given a cheap DVM that didn't work. I opened it and saw that the main selector switch was dependent on some loose spring contacts. I couldn't figure out how to fix that so I put in a spacer such that the case pressed on the switch. That fixed it and it works reliably now.
Repairing welding iron from sunkko709a - Page 1
Forum section: electronics / repair

author: Vldkk
author_rank: Newbie
timestamp: July 15, 2025, 09:11:47 am
content: HelloI need to repair welding iron from sunkko709a, i have 3 wires +/-/sig and 3 places for solder but i dont know which goes where. Does somebody know how to solder it? I attached photoThanks
Repair/Teardown calibration attenuator HP 11708A - Page 1
Forum section: electronics / repair

author: d-el
author_rank: Regular Contributor
timestamp: August 30, 2025, 07:18:43 pm
content: I bought HP8481D + calibration attenuator 11708A on eBay. I received a package with only 11708A and it turned out to be non-working. There was a break on the female side, and about 50 Ohm on the male side.I teardown it apart out of curiosity:[ Specified attachment is not available ]It turned out that one end had a broken contact end. No fragment was found inside the case (factory defect?).Cut a strip from copper foil, bent it, soldered it.

author: d-el
author_rank: Regular Contributor
timestamp: August 30, 2025, 07:24:21 pm
content: Assembled it, checked it against the working 11708A:
REPARAR RIGOL MSO5074 - Page 1
Forum section: electronics / repair

author: DIEGO C
author_rank: Newbie
timestamp: February 24, 2023, 06:53:31 pm
content: Hi, I need help. Could someone tell me what my fault is due to?I connected an HDMI cable to a Samsung 32" lcd-tv to my RIGOL MSO5074 oscilloscope and it did not detect it. I turned the oscilloscope off and on again, already with the HDMI cable connected and it blocked me at the end of the load. (PHOTO 1)Turn off the oscilloscope again and turn it on. Lights of several keys (PHOTO 2) came on and go off. The screen does not light upthe oscilloscope remains blocked with the screen dark (PHOTO 3).If I then measure voltage with a digital multimeter at these points (PHOTO 4), the oscilloscope charge restarts and when it reaches the end of the charge it stays blocked. (PHOTO5) What could cause the oscilloscope to block?

author: apolkosnik
author_rank: Newbie
timestamp: March 18, 2023, 01:19:00 am
content: I took out my MSO5102 out of a box (it was working before), and powered it on. It hangs with a black screen now, any clues?

author: electron1999
author_rank: Newbie
timestamp: October 11, 2024, 01:14:15 am
content: ¿Encontaste alguna opción a la falla de tu equipo?Tuve la oportunidad de comprar uno en caja abierta. Impecable al llegar, pero pasa lo mismo: Sólo encienden algunas luces y no hace más.

author: unseenninja
author_rank: Regular Contributor
timestamp: October 11, 2024, 12:57:03 pm
content: Quote from: electron1999 on October 11, 2024, 01:14:15 amThe working language of the forum is English. Please use it.

author: electron1999
author_rank: Newbie
timestamp: October 11, 2024, 06:36:31 pm
content: I appreciate your point and correct now... Sorry!Thanks!

author: thm_w
author_rank: Super Contributor
timestamp: October 11, 2024, 09:50:42 pm
content: Quote from: electron1999 on October 11, 2024, 01:14:15 amCan you still return it?Does repeatedly pressing the "Single" button do anything when powering on?
Reparation Hameg HM604-2 - Page 1
Forum section: electronics / repair

author: skopg
author_rank: Contributor
timestamp: July 27, 2023, 07:03:17 pm
content: Bonsoir à tous,je suis nouveau et novice en électronique...Je viens vers vous car j'ai 1 Hameg HM 604-2,et il ne fonctionne plus...j'explique j'allume il y a un signal sur l' écran (ligne horizontale que je ne peux que déplacer en X), si je bascule Off Search Delay sur Del TRIG là aussi la lampe s'allume (photo1).Si je teste un composant , il y a le signal en L sur l'écran, juntion BC voire dans la notice M17 604-2 (photo2).Mais si je tourne ou enfonce sur n'importe quel bouton RIEN ne se passe...Attendez-vous à m'aider et me dire quel serait le(s) composant(s) à changer.Merci pour votre retour.ElectroniquementVotre.Skopg

author: Swake
author_rank: Frequent Contributor
timestamp: July 28, 2023, 02:16:31 pm
content: Bonjour,Ce site étant anglophone, je vous conseille de poster vos messages en Anglais.Not having first hand experience with that scope but it appears that it is somehow 'locked' in the component tester mode. I believe the component tester mode will disable the timebase. There is a button on the scope to activate/deactivate that mode. Release that button, and if it still does not work then measure it to see if it works as expected.Always good to do is to verify all power supply rails are within spec.

author: Swake
author_rank: Frequent Contributor
timestamp: July 28, 2023, 02:19:49 pm
content: It looks from the first picture you have the 'MAG' button depressed. That thing acts like a zoom and this might explain why in component mode the beam takes the full screen width.
reparaton gw instek gsp 830 - Page 1
Forum section: electronics / repair

author: bossuet77
author_rank: Newbie
timestamp: May 13, 2023, 04:56:03 pm
content: bonjour à tousj'ai mis en panne mon analyseur de spectre gsp 830.je l'ai alimenté en 19V au lieu de 12 Vmaintenant un relais claque sur la carte mère mais le voyant de mise en marche reste éteintje recherche le manuel de service ou au moins le schemamerci de votre aide

author: tunk
author_rank: Super Contributor
timestamp: May 13, 2023, 05:04:24 pm
content: English please, maybe you could use google translate (or similar)?

author: Chris56000
author_rank: Frequent Contributor
timestamp: May 13, 2023, 06:20:45 pm
content: It seems he's fed 19 V into it instead of 12 V somehow, frazzled something inside and he wants to know where he can get a circuit, to which he's got no chance – GW Instek never hand out anything technical !Chris Williams

author: bossuet77
author_rank: Newbie
timestamp: May 14, 2023, 06:27:48 pm
content: in english sorryHello everyoneI broke down my gsp 830 spectrum analyzer.I powered it with 19V instead of 12Vnow a relay clicks on the motherboard but the power light remains offI am looking for the service manual or at least the diagramThank you for your help
Reparing an active monitor - Page 1
Forum section: electronics / repair

author: stdcall
author_rank: Newbie
timestamp: August 06, 2024, 07:11:31 pm
content: Hi.I'm trying to repair my M-Audio BX8 active studio monitor.It had one bad cap (c56) and I replaced it, and by mistake I connected it reversed.After powring on, the cap exploded. I removed it and placed a new cap properly. but I can't hear anything no longer.I tested the CAP and it measured +32VDC. I also tested the other big cap (c53) and it measured 18VDC.I assume the power circuit is okay. where should I check next ? do you have pointers what should I check ?Schematics I found on the web are attached.Thanks ! Ramon

author: Gyro
author_rank: Super Contributor
timestamp: August 06, 2024, 07:51:26 pm
content: There are other voltage rails that you need to check before you can say that the power circuit is ok. C53 is on a completely different power supply section from C56. You need to check all supply rails - it could be that C56 exploding has shorted Q21 and pushed the +15V rail up to +32V. There may have been some knock-on effect on the -32V or -15V rails. You need to go round all supply rails methodically before you can move on to see what else might have been damaged.P.S. Disconnect the speaker units until you have done basic testing to avoid the risk of burning them out.

author: wraper
author_rank: Unknown
timestamp: August 06, 2024, 07:56:58 pm
content: You should check if electrolyte from the blown cap did not get onto electronics.
Reparing coarse adjustment knob on HP-105B - Page 1
Forum section: electronics / repair

author: tkamiya
author_rank: Super Contributor
timestamp: December 13, 2020, 03:08:01 am
content: I just went through a process of experimenting and repairing a fiber glass shaft extension for 11801 adjustment on HP-105B. Mine was there but the fiberglass shaft was so damaged by heat that it no longer functions as needed. A little metal tab that acts as screw driver blade at the tip of fiber glass piece has come completely loose.I went through iterations but what finally worked was to cut off the original piece and glue in a tip harvested from ceramic tip screw drivers. I used this screw driver for parts. A small hobby lathe was used to drill a coaxial hole onto fiber glass shaft. As attached image will show, the finished part is a little shorter than the original, but it still works well.https://www.ebay.com/itm/ENGINEER-DA-72-Ceramic-Driver-0-4x2-4mm-Stock-in-USA/172416675691?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649Please see
Reparing HP8566B YTO unlock in 2-22 mode only - Page 1
Forum section: electronics / repair

author: tkamiya
author_rank: Super Contributor
timestamp: January 31, 2021, 07:03:48 pm
content: I am working on an HP8566B with an weird YTO unlock issue. It works fine with no sign of problem if it is set to 0 - 2.5GHz mode. Problem only happens when it is set to 2 - 22GHz mode. There are no obvious blown tantalums. Tried setting to center frequency 12GHz and bandwidth 2GHz down to 100KHz to see if scanning width was the issue. YTO unlock continues.Have anyone experienced something like this? Because it is working 0 - 2.5GHz mode, I have not done detailed voltage test. Logically thinking, it should not be necessary but I can.Any opinions, ideas, and solutions are very welcome.

author: Runco990
author_rank: Frequent Contributor
timestamp: February 01, 2021, 02:31:50 am
content: Have you had a look at this? I have repaired BOTH my SA's with this problem.

author: tkamiya
author_rank: Super Contributor
timestamp: February 01, 2021, 02:37:41 am
content: Yes, I did. As far as I can tell, my case is unrelated to Kerry's problem. In fact, I kind of follow his blog and knew of his experiences. My back hurts for lifting those heavy units. I have several here, so actually, I swapped all of those cards with a known working one and saw the problem reproduce.Thanks.