hybridfree/eevblog-posts huggingface dataset:
Audiolab 8000P service manual or schematic - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: December 14, 2023, 10:32:21 am
content: I'm asking again if anyone has either available for an early model 8000P 100W Amplifier (serial no. 209E59133).I am fairly sure that a schematic at least is available on hifiengine.com, but that site isn't accepting new registrations so I can't DL the file.If anyone has either the service manual or schematic I am happy to pay fair scanning fees.ThanksDavid

author: audiotubes
author_rank: Regular Contributor
timestamp: December 14, 2023, 12:03:07 pm
content: Dumb question, but did you contact Audiolab? The head office is / was in the UK although their stuff is mostly made in Taiwan nowadays. Hopefully they would be willing to help.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: December 14, 2023, 12:15:06 pm
content: CheersAlex

author: perdrix
author_rank: Frequent Contributor
timestamp: December 14, 2023, 05:57:16 pm
content: I did contact them. They said:Quote

author: audiotubes
author_rank: Regular Contributor
timestamp: December 14, 2023, 06:31:11 pm
content: Quote from: perdrix on December 14, 2023, 05:57:16 pmFound a couple of sites (attached a copy here also)I closed the first link, this is the 2nd one I foundhttps://elektrotanya.com/audiolab_8000p_sch.pdf/download.htmlI guess thishttps://www.diyaudio.com/community/threads/audiolab-8000p-and-coffee.302668/is not you, but if you know about it already sorry for the distraction.

author: perdrix
author_rank: Frequent Contributor
timestamp: December 15, 2023, 02:19:29 am
content: The diyaudio post is me... Thanks for the schematic, if I can get the full SM even better, but at least I have some data to work with if it goes AWOL.Thanks again, David

author: audiotubes
author_rank: Regular Contributor
timestamp: December 15, 2023, 12:53:26 pm
content: Glad to hear
Audiolab 8000Q Pre-amplifier Service Manual - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: November 08, 2019, 12:32:04 am
content: Does anyone know of a location where I can DL a copy of this? I found a few sites offering me the option to buy a PDF of this, but they all struck me a bit "dodgy" so I didn't proceed.Any pointers most welcomeThanks, David

author: andy3055
author_rank: Super Contributor
timestamp: November 08, 2019, 05:24:22 am
content: Can't find any info but this might help you:https://liquidaudio.com.au/audiolab-8000q-preamplifier-repair/
AUL Instruments TVM4 multimemeter - Page 1
Forum section: electronics / repair

author: Neil Barlow
author_rank: Newbie
timestamp: January 13, 2022, 04:31:01 pm
content: Hi Folks,Recently, I have acquired an AUL Instruments Model TVM4 transistorized voltmeter (probably ca. late 60's , early 70's). After fixing a few obvious problems, the device appears to be operating on most or all functions, but is quite out of correct calibration. I don't have a manual or schematic. Thus, I am unsure as to the function of the some the adjustments available on the circuit board. I may still have one or two undiscovered electronic problems on the board as well.A search of the net has not turned up anything in the way of a manual, schematic, or cal procedure. Is there someone here who could point me in the right direction?Thanks much!Neil
AUO T320HVN05.0 TCON Board from Samsung TV - Identify Diode - Page 1
Forum section: electronics / repair

author: xyberlink
author_rank: Contributor
timestamp: April 09, 2024, 03:25:48 pm
content: Hi,I have a Samsung UE32H5000AK TV that no longer turns on.The red standby light stays on all the time, but goes off for a split second approx. every 10 seconds when I think it's trying to start, but then shuts down.After investigation, it looks like Diode D113 on the TCON board is shorted.I'm struggling to determine what type of diode it is. The markings are "LS 47 LG" and it looks like a DO-214AA (SMB) package. I can't find anything online to assist.From research, I think it may be a TVS Diode. If that's correct, then I'm not sure what would be suitable values...Polarity: ? (I'm thinking unidirectional)Stand-Off voltage: ?Maximum clamping voltage: ?Breakdown voltage min/max: ?TCON board input is 12v. Fuse F101 is fine (annoyingly). Board is an AUO T32HVN05.0 Ctrl BD 32T42-C02Any help much appreciated.Thanks.

author: fzabkar
author_rank: Super Contributor
timestamp: April 09, 2024, 06:01:48 pm
content: It does look like a TVS diode with abreakdownstandoff voltage of 13V. That does make sense since the supply voltage is 12V.I would disconnect the PCB and confirm that the 12V supply is correct. If so, then remove the TVS diode and see if the TV runs without it.1SMB13AT3G, 1SMB13A, SMBJ13A100, SMBJ13CA, P6SMBJ13A, CD214B-T13A, TV06B130J-G, SMF13CA, SMBG13CAhttp://markingcodes.com/search/c/lg

author: xyberlink
author_rank: Contributor
timestamp: April 10, 2024, 01:30:56 pm
content: D113 removed - TV now working again.Power supply is marked up 13v and outputs 12.50v.Thanks for the info - I was searching for LS 47 rather than LG, but that does fit the requirement. I will source a replacement.
Aurora inverter fix - Page 1
Forum section: electronics / repair

author: fant
author_rank: Contributor
timestamp: September 14, 2025, 09:17:53 am
content: Good morning;I am trying to fix an Aurora inverter 15 years old.Has two problems, the famous E031 (solved changing the four relays on the power board) and now with another problema that looks like as it is not locking the 50 Hertz mains frequency.No alarm on the display, but not working.Probably is the mains reference frequency that is not injected on the microprocessor to synchronize the inverter.Has anybody or where is possible to find the schematic diagram?Inverter is the model PVI-4.2-OUTD-IT, P/N 3G79991A000, MFG date 29/10.Thank you in advanceMandi

author: Swake
author_rank: Frequent Contributor
timestamp: September 14, 2025, 01:28:03 pm
content: Or the mains is soooo dirty that it cannot sync.Or for some reason it cannot sense the mains (voltage sensor dead, or not connected).Or mains is over 253V.Or input voltage is really low.Or no ground.Or too much DC on the output.Or some frequency related settings are off or corrupt (try factory reset).You might want to check for an AC sense circuit: transformer / sensors / resistor divider / filters.I don't have a schematic, only a block diagram, see attched.Autora is part of ABB now. ABB might have a schematic available. As you probably guessed the 'IT' in the model name is for Italy, there are other suffixes, will be a very similar machine.

author: fant
author_rank: Contributor
timestamp: September 14, 2025, 02:13:46 pm
content: I have tested everything, all the options you mention, but no sync.I have begun to follow the traces to see where the 230 Vac is carried, but a schematic diagram will help.I have all the brochures and manuals bot ABB and power one, but no schematic available.For this my request.Thanks
Australian Imark 5020RM service manual or similar, and schematic - can you help? - Page 1
Forum section: electronics / repair

author: minsik
author_rank: Contributor
timestamp: March 02, 2024, 10:39:26 am
content: Hi, looking for a schematic or more detailed information on an Australian Imark power supply/battery switch/charger if possible.Imark 5020RM is the item can you help?thanks Minsik
Automated Band Saw - Page 1
Forum section: electronics / repair

author: Systemtek
author_rank: Contributor
timestamp: October 26, 2020, 09:08:46 pm
content: Hi,Looking for some suggestions but I have a lead to follow too. I'm helping out a friend with an old piece of machinery.It's an old automated band saw that is stopping after a short but varying time and the LCD display is mostly showing solid blocks but some characters after the boot screen.In the electrical cabinet on the machine there is a linear power supply, a PLC, contactors etc and a UI with an LCD display, hard switches and a basic keypad. The board running the display and keypad is getting 5.02v at it's terminals which is then fed to a filter.The filter has been modified! The input goes to a ceramic and an electrolytic but the trace taking the power from the ceramic to the electrolytic has been cut and a resistor (or inductor?) has been bodged on bridging the gap. 4.8v makes out onto the board after the filter and I tested VCC to ground on a few of the ICs and they are all receiving this with no more drop. I only had time to check the data sheet on the flash chip which state +- 10% in a 5v input.My first guess looking at the symptoms before I arrived was a poor filter on the controller and or an inductive load (maybe with a failed flyback diode) sending noise back through an output.The electrolytic tests as having 0.2ohm ESR in circuit and correct capacitance but is old and when I connected the ESR meter one of the 3 or 4 times I tested it, it showed 0.25pF. Maybe a failed connection inside the electrolytic? Combined with the modification to the input filter is changing the electro a good course of action? I have an electrically suitable cap to try it with but may need order a different shape to fully complete the repair if I get good results.Also when I tested AC across the power supply filter and the input to the UI board with my meter a stable voltage regularly and consistently appeared but this was not there using my friends meter and the DC voltage is stable in both cases so it doesn't seem to be heavy loading and dry caps causing the AC to appear.This 'UI' board is actually a stack of 2 PCBs one of which is attached to the display and has black blobs on the ICs.Could it be that the keypad is contaminated and causing it stop maybe?all any ideas welcome, thanks
Automotive SMD resistors - Page 1
Forum section: electronics / repair

author: Audiorepair
author_rank: Frequent Contributor
timestamp: May 11, 2022, 06:08:43 pm
content: I don't normally repair car stuff, but this was foisted on me today by a friend who didn't want to take no for an answer, as it would cost him dear otherwise.It's a BMW media control unit, which sits in the boot of the car, apparently.It had some water damage, including a 1 ohm resistor which needs replacing.I haven't seen SMD resistors like these before, and scrolling through those available at Farnell I didn't see anything that looked similar, so I don't know why they are packaged like this.I suspect from the circuitry they are not massively high power, maybe this is some kind of environmental car thing instead.Photo attached.

author: TheMG
author_rank: Frequent Contributor
timestamp: May 11, 2022, 06:20:00 pm
content: I believe those are inductors, not resistors.Likely 1uH (1R0), 10% tolerance (K).Why they use "R" in the numbering for an inductor, I don't know, but that's something they do.From the triangle and the letter T, looks like TDK / EPCOS part.https://product.tdk.com/en/search/inductor/inductor/smd/list#ref=characteristic&2l%5Bunit%5D=1.00E-06&2l%5Bt%5D=1&2ltol%5B%5D=%C2%B110%25&psts%5B%5D=0&_l=20&_p=1&_c=part_no-part_no&_d=0

author: Audiorepair
author_rank: Frequent Contributor
timestamp: May 11, 2022, 06:24:59 pm
content: Doh!I think you are correct.Exit stage left hoping nobody notices.

author: inse
author_rank: Super Contributor
timestamp: May 12, 2022, 04:46:23 am
content: Is one of them open, or how did you diagnose it to have failed?It looks like some kind of supply line filtering, you could bypass the coil for test purpose.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: May 12, 2022, 06:07:30 am
content: Quote from: inse on May 12, 2022, 04:46:23 amThe PCB was corroded, the inductor was detached from one pad, and when I removed it the corroded solder terminal fell off.I can't test this module, I don't have a BMW to plug it into.I am repairing it with the understanding I can only repair visibly obvious faults, and can't test it.This why I don't repair car stuff.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: May 12, 2022, 01:02:20 pm
content: Quote from: TheMG on May 11, 2022, 06:20:00 pmThanks,I found this at Farnell, looks like it will do the job.https://uk.farnell.com/tdk/nlcv32t-1r0m-efr/inductor-1uh-20-1-7a-100mhz-3225/dp/2747759
Autotronik developer menu - Page 1
Forum section: electronics / repair

author: radiofest
author_rank: Newbie
timestamp: November 06, 2024, 10:39:03 am
content: Good day! The manual for the Autotronic machine states that: IMPORTANT: Calibrations B,C,D,E,F are used only by the manufacturer.I need to calibrate the P-axis rotation motor, but I can't open these menus. Can anyone tell me how to unlock these manufacturer's calibrations?

author: HighVoltage
author_rank: Super Contributor
timestamp: November 06, 2024, 04:26:01 pm
content: Why don't you ask the software manufacturer?
AV Receiver Repair Help - Integra DTR-7.9/Onkyo TX-SR806 - Page 1
Forum section: electronics / repair

author: arattig
author_rank: Newbie
timestamp: November 08, 2024, 08:59:05 pm
content: Need help troubleshooting my receiver which goes into protect mode. Found a blown channel due to speaker wires shorting together and have replaced all bad components as well as recapped the pre and output amplifiers.The amp will turn on if i remove the preamp board, but immediately goes into protect when reinstalled. I had a donor preamp board that i installed with the same result going into protect mode. There was a fuse F4000 that was also blown on the the video pc board (U17) that i replaced.I've measured every component on the preamp and output amp boards, did not find any bad component. So, either i've inadvertantly skipped over a component measurement on these boards, or another circuit is at fault when the preamp board is plugged into the output amp board...connects another circuit somewhere else that is causing the excessive current draw, U17 board?Spent a few weeks going over all the youtube videos and chats i can find, so finally posting here.Link to service manual here, file was too large to post:https://www.manualslib.com/manual/1073303/Integra-Dtr-7-9.html
Avantest R3365 Spectrum Analyzer Power supply Schematic - Page 1
Forum section: electronics / repair

author: dstamer
author_rank: Newbie
timestamp: June 22, 2023, 07:13:44 pm
content: Does anyone have a schematic for an Advantest R3365 Spectrum Analyzer Power supply. I found a service manual online however it did not have the schematics for the power supply.The unit starts to power up then immediately all voltages drop to 0.So far no obvious components/capacitors look bad although some were leaking.Perhaps there is a circuit that checks status and turns off the supplies.Any ideas would be welcome.The power supply is made up of a main board and a large daughter card.Difficult to trouble shoot when both are connected.1/3/2023Fixed the issue. There were several leaky capacitors that had damaged the PCB.It ate away some of the PCB material and copper traces directly under the capacitors.Unable to see until removing caps. Cleaned, repaired, replaced caps. Working now.

author: lugaw
author_rank: Regular Contributor
timestamp: January 11, 2024, 11:57:11 am
content: Did you take pictures? How did you extract the power supply board from the case?
AVCOM SDM-42A tuning/manual - Page 1
Forum section: electronics / repair

author: rfclown
author_rank: Frequent Contributor
timestamp: February 09, 2021, 02:49:18 am
content: I just aquired an AVCOM SDM-42A Spectrum Display Monitor which turns out to be an 10.7 MHz spectrum analyzer of sorts. Google didn't turn up any manuals. AVCOM site doesn't show it (old instrument). I could post a question on their website, but haven't yet. I fed in 10.7 MHz from my sig gen (FM signal shown in picture). The fine tuning knob, input sensitivity knob, and center frequency trim adjustment all respond as expected. The span knob responds correctly, but... the center frequency moves alot with span adjustment.The only reference I found to AVCOM manuals was a comment in this forum topic about them not being available.This thing is made to visually monitor your radio's IF to see signals that you might be missing. I'd think that you'd want a center frequency that didn't vary with span for this to be useful. Any suggestions on finding help adjusting this thing before just opening it up?Aaahhgg! After posting this, I went to open it up, and the center fastener on each side is a rivet.
Avery berkel IM200 scales - Page 1
Forum section: electronics / repair

author: silly sausage
author_rank: Regular Contributor
timestamp: February 01, 2025, 04:25:56 pm
content: Hi folks, I have an avery berkel IM200 digital scale,it fails to fully boot up, It reads the hw+sw version and stops/hangs, I removed its main pcb, There is a battery on it that reads 0.6v, Would that stop it booting and can it be replaced with a nicad or lithium ion cell?, Avery says to replace the main board, There is a small ic near the battery no 7CA369KHCT125 It had green gook /crud between its pins that i have cleaned up,any ideas how to fix these scales?

author: m k
author_rank: Super Contributor
timestamp: February 08, 2025, 07:23:21 am
content: First you need a correct battery voltage, after that who knows.Replace the old one, it's Ni-MH are available.
Avo Megger BM80/2 beeping and shows E44 on display. - Page 1
Forum section: electronics / repair

author: Paceguy
author_rank: Regular Contributor
timestamp: July 29, 2024, 05:45:01 pm
content: I have an Avo megger model BM80/2 that when powered up beeps and shows E44 on the display no matter what position the function switch is in.I looked online to try to find the service manual with no luck. Help would be greatly appreciated. Thanks in advance.

author: trobbins
author_rank: Frequent Contributor
timestamp: July 31, 2024, 12:39:46 am
content: I have schematics for BM80-400 Mk2 - PM me. I have progressed some repair of my BM81/2, that also showed an E44. So far I had to replace an LM324 to recover a bad 2.5V reference line, and replace an LM339 to recover its nominal input node voltages, but BATTOK line is still pulled low when I think it should be nominally hi, so WIP but I last had this on the bench last year.Ciao, Tim

author: Paceguy
author_rank: Regular Contributor
timestamp: July 31, 2024, 04:53:29 pm
content: Thanks Trobbins, I will check that out.
avometer 8 mk1 reads high - Page 1
Forum section: electronics / repair

author: m3vuv
author_rank: Super Contributor
timestamp: September 19, 2021, 12:56:01 pm
content: hi all,i have an old avometer 8 mk1,came to me with the movement o/c,i replaced it with a good one along with the swamp resistor bobbin but it reads about %20 high on dc volts ranges,havent tested others yet,all the shunts test good compaired to a working one,tried moving the magnetic shint but still reads high,any ideas?

author: m3vuv
author_rank: Super Contributor
timestamp: September 20, 2021, 10:42:13 pm
content: i am very suprised no answers yet,maybe this is before everyones time?

author: George Edmonds
author_rank: Frequent Contributor
timestamp: September 21, 2021, 01:40:10 am
content: HiThe first step is to verify the 50 micro amp range preferably with another meter in series acting as a check meter.George G6HIG Dover UK

author: m3vuv
author_rank: Super Contributor
timestamp: September 21, 2021, 03:28:43 pm
content: i have done that,it checks out fine,ive also swaped the swamp resistor with a known good one,are the mk 1 and 2 the same electricaly?,if so i have a good mk2 that i can use to compair the shunts on the mk1 against.

author: George Edmonds
author_rank: Frequent Contributor
timestamp: September 21, 2021, 04:28:42 pm
content: I have tried to send you the AVO repair information without successPM me with an address that I can send it toGeorge G6HIG Dover UK

author: m3vuv
author_rank: Super Contributor
timestamp: September 27, 2021, 02:18:07 am
content: i have found resistors 2,3,and 4 o/c on the lower resistance board,can these be replaced with normal metal film resistors and 10 turn trimpots?,if i cant sort it it will get turned into an esr meter,like mt old braddley.
avometer model8 mk 1 reading high - Page 1
Forum section: electronics / repair

author: m3vuv
author_rank: Super Contributor
timestamp: November 05, 2020, 11:41:22 am
content: hi all,ive just got one ov the above,on the dc volts ranges it reads high,ie ,an 8 volt input reads about 12v on the meter,ive not checked the other ranges yet,i will post in the test gear section too,has anyone any idears where to look?,ive read it could be the universal shunt,any idears where its located?,looks like the meter swamp is u/s as well,ive the service manual but cant find anything related,any help welcome to get this dinosaur usable is most welcome,cheers Paul m3vuv.,also posted in the test gear section

author: tggzzz
author_rank: Super Contributor
timestamp: November 05, 2020, 11:47:32 am
content: The answer is in your other thread
AVX (?) Tantalum caps giving odd reading - TDS3000B Battery board schematic - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: March 08, 2021, 10:55:15 am
content: i'm trying to locate the source of some apparent ripple on the trace of my TDS3000B. All the capacitors on the Artesyn 15V supply appear good, and I'm now looking at the battery board of my TDS3000B. There are two yellow AVX caps which I think are TAJY156K025RNJ (15uF, 25V, Case Y).One of them is giving me a very odd reading on my BSide ESR02. The one to the right (C870) is reported as 987uF, ESR 0.28, while the other (C260) is reported as 16uF, ESR 0.3 (which sounds about on the money).I suspect that something else in the circuit is confusing the ESR02. Did anyone ever reverse engineer the battery board circuit?ThanksDavid

author: madao
author_rank: Frequent Contributor
timestamp: March 08, 2021, 11:35:57 am
content: 156E = 15^6 = 15 000 000 pf = 15 µFE = 25V ratingYou're right with value of 15µFnearly 1 mF = , probably high leakage current has influenced to reading of RCL Meter (?)Have you desolder and check tantal ? In ciruit measurement with RCL Meter isn't possible in most case.
Axis P5635-E MK II PTZ - PoE not working - Replace NCP1081 but chip is EOL? - Page 1
Forum section: electronics / repair

author: CrazyFin
author_rank: Newbie
timestamp: January 28, 2025, 08:50:15 am
content: I have an Axis P5635-E MK II PTZ that has stopped working and after some research I have found a couple of interesting threads here in EEVBLOG and on other forums on the internet.It seems that a common pulprit on various AXIS cameras is the NCP1081 PoE-chips that fails. On some cameras there is one chip and on most other series such as the Q60 series and P55 as well as P56 series it seems to be two chips. People who have replaced those chips has been able to get their cameras up and working again.https://www.eevblog.com/forum/repair/axis-q6034-e-speed-dome-cam-no-power/One way to verify this seems to be to apply 24VDC to the external connector on the camera as described for example here:https://ipcamtalk.com/threads/axis-p55-q60-multi-connector-cable-pinout.78088/Anyway, I will try to replace the NCP1081:s on my camera but it seems that the NCP1081 is now End-Of-Life:https://www.onsemi.com/products/power-management/poe-powered-devices/NCP1081I can find NCP1081 on eBay and other various sources but the sellers seems to be in China so I am afraid those chips being fake ones like many other components sold from Shenzhen, China. Has anyone of you that have repaired your cameras recently with NCP1081 found a reliable source that are selling NCP1081 that are not fake?
AXOR Minispeed 60 analog servo driver failed.  Troubleshooting help needed. - Page 1
Forum section: electronics / repair

author: Ian.M
author_rank: Super Contributor
timestamp: July 04, 2019, 01:15:54 pm
content: Hi guys,I've got anAXOR Minispeed 60servo drive, used in what's basically a robot arm, that's failed. It immediately indicates axis tripped in the control software (which is propitiatory and highly application specific).The fault has been localised by substitution to the Minispeed 60, and we believe to its small signal daughter-board. There was no damage visible on a close visual inspection of the daughter board.I've just assembled an extender card so we can make measurements under power in situ, and have a spare DIN41612 connector so may be able to make up a bench test harness for it.Any assistance from anyone familiar with the Minispeed drives would be appreciated. A service manual or schematic would be particularly useful.Unfortunately I am only on site one day a week so any measurements requested will take a while.
Azonix A1011/Omega DP-95 RTD Thermometer - Page 1
Forum section: electronics / repair

author: zorktronics
author_rank: Newbie
timestamp: May 26, 2022, 07:47:14 pm
content: Hi everyone, I am working on one of these thermometers, replaced several capacitors, a mosfet and it worked with a beyond acceptable deviation, variable on all channels. Does anyone have the complete manual of this thermometer? After erasing the configurations, all channels came disabled and the omega's manual don't help on anything beyond the basics. If anyone have the complete Azonix manual or at least the contents of the 2864 it will help to recover this instrument.
Backlight Fail + Coil Whine on Philips Monitor (234cl2sb) - Page 1
Forum section: electronics / repair

author: Pilgo
author_rank: Newbie
timestamp: July 15, 2020, 05:04:59 am
content: Hey guys,I'm trying to repair e 9-ish years old monitor (Philips 234cl2sb) that started with some whining a while ago. Last week the backlight started failing. Sometimes, when I turn on, the backlight works fine (with some intense whine), sometimes there're w few leds (the position changes randomly) turned off on the right side and sometimes the backlight doesn't work at all.At first I didn't bother cause I was planning on replacing it, but now tides have turned and I'm up for the salvage.I've narrowed the whine to the vicinity of the 4.7uF/100v capacitor. I replaced it but the problem persists.I'm a beginner when it comes to electronics. I know my way around a multimeter and a soldering iron but I have no formal education. So any help would be immensely appreciated.Can this be salvaged without replacing the whole board?

author: TheMG
author_rank: Frequent Contributor
timestamp: July 15, 2020, 06:39:13 pm
content: I think the root cause is bad LEDs in the backlight itself. The coil whine is probably due to the backlight driver running outside of its normal range trying to keep a constant LED current despite the bad LEDs.

author: Pilgo
author_rank: Newbie
timestamp: July 16, 2020, 01:22:39 am
content: Thanks for the reply!It whines when all LEDs are turned on, so that would be within the normal operation conditions for the driver, wouldn't it?Wouldn't a bad LED simply stop working, since it's a simple component?In case it is, indeed, the LEDs. Can they be replaced? I'm under the impression these backlight panels use some sort of small factor LED that can't be replaced manually.EDIT: It appears that if I leave the monitor working for a while and then restart it, the backlight works. It's like it needs some "warming up".
Bad 53131A PSU - Page 1
Forum section: electronics / repair

author: tombi
author_rank: Regular Contributor
timestamp: May 11, 2016, 08:57:01 am
content: Hello,I (perhaps mistakenly) bought a broken 53131A with a dead PSU. Seller said it had the oven option - it didn't. Seller said it hadn't been opened - the power supply board hadn't even been screwed back in and it rattled when it got to me.Worse there are parts missing off the PSU.It is one of the Delta SMP-43DL units (different to the ones I have seen here on the forum). Same as this one but stuffed if I am paying that for it.http://www.ebay.com/itm/0950-2139-SMP-43DL-Power-Supply-T61610-/361530977124?hash=item542ceceb64Anyway the tricky part is the main switching MOSFET is missing (it appears to have exploded).The bulk capacitors seem to have been replaced with 47uF 250V units. 47uF seems too low and 250V is definitely too low (might have gotten away with that in the USA but not here in Australia).Finally there is a zener diode ZD1 right near the switcher heat-sink that is gone.It doesn't match the schematics for the 531XX PSU previously posted - it doesn't have the controller chip for starters.Does anybody have one of these they could take a peak at for me? Or better a schematic.Tom

author: w9gb
author_rank: Contributor
timestamp: September 17, 2019, 03:05:09 pm
content: DELTA GROUP ELECTRONICS in Thailand was OEM Suppliers of this Switch-Mode Power Supply.Model Number: DPS-43DL-2https://www.deltathailand.com/en/==Radwell (PLC Center) in New Jersey have DELTA GROUP ELECTRONICS DPS-43DL-2 / DPS43DL2(USED TESTED CLEANED) POWER SUPPLY “In Stock” (100/240V, 2 Amp, 47W, 50/60Hz).eBayhttps%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F391748630351Radwell Product Page (They offer a Repair Your Board Service)https://www.radwell.com/en-US/Buy/DELTA%20GROUP%20ELECTRONICS/DELTA%20GROUP%20ELECTRONICS/DPS-43DL-2Radwell International1 Millennium DriveWillingboro, NJ 08046USA

author: tombi
author_rank: Regular Contributor
timestamp: September 17, 2019, 03:14:40 pm
content: Thanks for the tipBut $300USD Ouch.I figured it out in the end. I found a similar PSU for sale somewhere and the seller kindly read the number off the transistor (was a BUV48A).I would like to replace the PSU board someday as it is pretty charred in places and I don't trust it. It is working again though. I just don't trust it enough to leave it on unattended.Annoyingly it is easy to find 5v,+/-12V supplies but the extra -9V is a pain. Sure I could build something (and maybe I will).Tom
Bad connection causing crackling in JBL noise cancelling headphones - Page 1
Forum section: electronics / repair

author: canadaboy25
author_rank: Regular Contributor
timestamp: September 03, 2018, 10:46:54 pm
content: Hey guys, I've got a pair of JBL over-ear noise cancelling bluetooth headphones. Basically I really like the headphones compared to others I have tried but they have a manufacturing flaw. Dozens of one star reviews online due to a very loud crackling that develops in the right ear. I have already returned a pair due to this issue and my second pair is now displaying the same symptoms.Basically if you twist upwards on the right ear cup slightly it causes a deafening crackle. If you manage to get it in exactly the right position it seems as if the noise cancelling function in the right ear stops working completely. However, if you turn the noise cancelling feature off, you can still use them as bluetooth headphones with no issues.This makes me think it is just a bad connection that develops to the speaker but I'm not sure that would cause a deafening crackle. Perhaps the microphone used for the noise cancelling function?I would take them apart but they are held together with special safety screws so I'll have to wait for some bits to come before I can open them.Just wondering what you guys with more experience about audio systems think the fault may be.Here is a link to a short video displaying the issue.https://youtu.be/-Lp08N-wF-YThanks

author: ML
author_rank: Newbie
timestamp: September 19, 2018, 02:44:09 pm
content: Hi,have you maybe solved the issue? I've got a pair of JBL headphones (E65BTNC but they look pretty similar to yours) with the exact same problem - a crackling noise in the right ear when you wiggle the can and only with noise cancelling on. It's really annoying. I can't bring them in for a warranty repair as I'm far from home for the next few months.

author: bishupz1
author_rank: Newbie
timestamp: April 28, 2021, 03:18:51 am
content: I have the JBL 750 nc headphones. The left ear-cup crackles when i have Noise Cancelation "ON", when it is turned off they are perfect... I did the factory reset and it didn't solve anything. My best guess is that it is a warn out wire that is possibly the microphone for the noise cancelation... Just throwing something out there... I would like to repair the headphone but i would like to hear if anyone has solved this porblem/found out what the problem is.
Bad display on Dell Latitude c600 - need sugestion from a video recording - Page 1
Forum section: electronics / repair

author: Latino16bits
author_rank: Newbie
timestamp: August 08, 2025, 08:35:19 am
content: I need advice/sugestion to know what part might be bad, Is the inverter or the flex cable or what else?I was opening and closing the lid like a normal laptop would but without having the screws for the hinges so i believe the flex cable pulled in some wrongfuly way. I did reinsert the flex cable but this time nothing got fixed. I have 2 spare flex cables and 2 inverters for this specific laptop model latitude c600.
Bad MOSFET in brushless motor driver - Page 1
Forum section: electronics / repair

author: leestrong
author_rank: Newbie
timestamp: September 04, 2021, 09:04:34 am
content: On a quadcopter All-in-one board, 2 MOSFETs on one of the brushless motor driver are dead (connectivity between source and drain), causing burnt motor windings. The markings on the 2 MOSFETs are "L0302A 2121A" and "L0302A 2119A", any idea what those are?Attached please find the image of both sides of the board, the dead MOSFETS are circled in red.Possible useful information: the All-in-one board is "GEPRC GEP-F411-35A AIO", the motor driver's max continuous current is rated at 35A, and burst current at 40A.Thank you in advance for the help.

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 04, 2021, 10:23:24 am
content: 30V 1.2mΩ N-Ch Power MOSFETJMSL0302AU,DatasheetYou should easily find a compatible replacement, ex.IRF5300, cheap and available in AliExpress.

author: leestrong
author_rank: Newbie
timestamp: September 05, 2021, 08:15:17 pm
content: Thank you DavidAlfa!
bad output on my homebrew psu - Page 1
Forum section: electronics / repair

author: m3vuv
author_rank: Super Contributor
timestamp: January 29, 2020, 05:41:56 am
content: Hi all,ive a 0-30v o-20amp psu,the output looks like a sort of 3phase ac signal on my scope,if i put a .1farad cap on the psu output the trace is flat dc,does this indicate bad filter caps or a bad diode in the brige rectifier?,cheers in advance.

author: m3vuv
author_rank: Super Contributor
timestamp: January 29, 2020, 05:44:48 am
content: heres the cap im testing with on the psu output.Its 100.000uf at 50v.the original filter caps i used were 4x 3000uf but chinese

author: xavier60
author_rank: Super Contributor
timestamp: January 29, 2020, 11:27:06 am
content: What is the ripple frequency? Is the ripple present while the PSU is unloaded?Is there a schematic of it?

author: m3vuv
author_rank: Super Contributor
timestamp: January 29, 2020, 01:44:39 pm
content: i dont know the ripple frequency yet as havent meashured it,its there all the time loaded or not tho.

author: xavier60
author_rank: Super Contributor
timestamp: January 29, 2020, 10:04:11 pm
content: Why does the oscilloscope trace have bright and faint segments?

author: m3vuv
author_rank: Super Contributor
timestamp: January 30, 2020, 03:46:22 am
content: its down to the shutter on my phone camera,its ok in reality.

author: schmitt trigger
author_rank: Super Contributor
timestamp: January 30, 2020, 04:16:53 am
content: -No schematic or basic circuit description.-Ambiguous problem description and troubleshooting.-Poor quality and not useful images.It will be *very* difficult to provide you with an accurate advice.

author: tkamiya
author_rank: Super Contributor
timestamp: January 30, 2020, 05:13:33 am
content: You have your scope set up on AC coupling. So what you are seeing is not the entire output. You are seeing fluctuation of your output. DC offset is not part of the display. I see your scale setting is at 2V. Whatever is happening is not normal. I'd say your power supply is oscillating.Please either describe your post your circuit.
Bad RS422 signal? - Page 1
Forum section: electronics / repair

author: Alex_Baker
author_rank: Frequent Contributor
timestamp: August 09, 2024, 08:52:48 pm
content: I am attempting to read RS422 data from a Lowrance HDS9 sonar/chart plotter. It can output and recieve data through a 4-wire RS422 interface. I am having troubles reading data and decided to use an oscilloscope. The below image is what I captured by putting the scope probe on the two TX wires.I do not have much experience with RS422, but this looks bad. Can anybody confirm this suspicion?

author: hexreader
author_rank: Frequent Contributor
timestamp: August 09, 2024, 09:16:55 pm
content: First thing to do is change oscilloscope channel 1 coupling from AC to DC... or use channel 2, which is already DC coupled.

author: Alex_Baker
author_rank: Frequent Contributor
timestamp: August 09, 2024, 09:39:07 pm
content: Dang, I can't believe I did that.Probing a "good" rs422 signal looked fine with channel 1 though, so I don't think that is necessarily the problem. Unfortunately I wont be able to do more testing until Monday, this equipment is at a school lab.

author: hexreader
author_rank: Frequent Contributor
timestamp: August 09, 2024, 09:55:08 pm
content: Another thing - trigger on falling edge, not risingGood luck

author: Alex_Baker
author_rank: Frequent Contributor
timestamp: August 09, 2024, 09:57:22 pm
content: Quote from: hexreader on August 09, 2024, 09:55:08 pmThat would not change how the signal looks, would it? why would it matter?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 09, 2024, 10:12:55 pm
content: Note that you need either an isolated bus or scope to probe it that way. You may find it better (or necessary in general) to tie both probes to circuit ground then probe the two sides of the bus and use MATH to subtract the two signals.Tim

author: hexreader
author_rank: Frequent Contributor
timestamp: August 09, 2024, 10:43:01 pm
content: Quote from: Alex_Baker on August 09, 2024, 09:57:22 pmThe difference is minimal for most circumstances, but try both ways.Rising edge may be good enough, but see if you can work out for yourself why falling edge would usually be preferred.

author: tooki
author_rank: Super Contributor
timestamp: August 09, 2024, 11:21:10 pm
content: Give that there should always be a ground on RS422/RS485, one can just probe each signal individually. Subtracting the two shouldn’t really be necessary, but is certainly doable.
Bad Snubber Diode - Page 1
Forum section: electronics / repair

author: Yellow Hotel
author_rank: Newbie
timestamp: January 14, 2023, 04:40:42 am
content: Hey, so I have this treadmill I've been working on and basically it keeps blowing out this one particular mosfet, I believe its because the snubber diode has gone bad and I wanna replace it but the problem is I can't find anything when I look up the number on the part (the part that I think is the snubber diode anyway) and so I want to just go ahead and wire one on there in parallel with the dc motor.So my question is what kind of diode would be a suitable candidate for this application? The treadmill motor is 14.3 amp 2.0 HP if that makes a difference.Thanks

author: R-1125F
author_rank: Regular Contributor
timestamp: January 14, 2023, 03:06:59 pm
content: What's the part number that you have? One of these could workhttps://m.littelfuse.com/~/media/electronics/datasheets/tvs_diodes/littelfuse_tvs_diode_1_5ke_datasheet.pdf.pdf

author: Yellow Hotel
author_rank: Newbie
timestamp: January 15, 2023, 12:09:43 am
content: The part number is hfa15p860, and actually when I just double checked it again it came up as "a state of the art ultrafast recovery diode" so I guess I was correct about which one was the snubber

author: bdunham7
author_rank: Super Contributor
timestamp: January 15, 2023, 12:23:56 am
content: Are you sure that isn't HFA15PB60, also HFA15PB60-PBF?Updated version here:https://www.mouser.com/ProductDetail/Vishay-Semiconductors/VS-HFA15PB60-N3?qs=sGAEpiMZZMtbRapU8LlZD1lzHSyyeiTHkd%252BEgKVZLdg%3D

author: fzabkar
author_rank: Super Contributor
timestamp: January 15, 2023, 12:27:57 am
content: Datasheet:https://www.infineon.com/dgdl/hfa15pb60pbf.pdf?fileId=5546d462533600a4015355bfe01115d7

author: Yellow Hotel
author_rank: Newbie
timestamp: January 15, 2023, 12:58:48 am
content: So it turns out that the original part hfa15p860 is also known as SP001559354, and when I looked that up I still couldn't find any for sale; however I did find a list of substitute parts on digikey where I bought a VS-HFA15PB60-N3, I guess I should have dug a little deeper before making the thread.... well anyway the replacement is on the way so thanks everyone who replied
Baku 858A smd hot soldaring station problem - Page 1
Forum section: electronics / repair

author: AkibUddin
author_rank: Contributor
timestamp: November 13, 2022, 11:17:22 am
content: Tempareture LED on all time & tempareture adjustment knob not working but both potentiometer still good condition and abnormal exciting heat,Air flow system still good condition,moc3041 & triac still good condition, moc switching 3.6v Ziner change but still over heat
Ballantine 6130 Time Mark Generator - Page 1
Forum section: electronics / repair

author: barry14
author_rank: Regular Contributor
timestamp: September 17, 2015, 08:18:29 pm
content: Anyone know where to get the manual for the Ballantine 6130A Time Mark Generator? Thanks.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 17, 2015, 08:29:42 pm
content: A manual or will just the schematics do?http://www.opweb.de/en/model.php?id=8469

author: barry14
author_rank: Regular Contributor
timestamp: September 20, 2015, 09:00:08 pm
content: Thanks but I already found that site. I really would like the entire manual especially the calibration section.

author: Rax
author_rank: Super Contributor
timestamp: January 18, 2022, 06:14:47 am
content: Old topic, but really - no one has a decent manual for this?
BANANA PHILIPS PM2525 - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: January 23, 2021, 10:37:57 am
content: Good morning all! I am looking for the wiring diagram of the small card used to put the 4mm banana plugs on a PHILIPS PM2525 multimeter (photo attached); because the cards being broken, I was able to replace them, but this card is missing. The diagram that I have does not give the details of the connection. If anyone can help me; I thank him in advance. Cdt

author: lionelkjh
author_rank: Frequent Contributor
timestamp: January 23, 2021, 11:06:03 am
content: the fallowing....

author: picburner
author_rank: Frequent Contributor
timestamp: January 23, 2021, 01:52:17 pm
content: Is it the DIN socket card you are missing?Some information can be foundhere.Artek Manualshas the PM2525 service manual with schematics.

author: lionelkjh
author_rank: Frequent Contributor
timestamp: January 23, 2021, 03:06:50 pm
content: re; I was talking about 4mm banana plugs, and not the plug below to measure weak resistances (4-wire method) ...

author: lionelkjh
author_rank: Frequent Contributor
timestamp: January 24, 2021, 01:38:35 pm
content: Hello; I am attaching precisely the photo of the card that I do not have on my PM2525, and its diagram on the service manual is not there .... Thank you for your help!
'Bangybang tubes' total morons, - Page 1
Forum section: electronics / repair

author: CaptDon
author_rank: Super Contributor
timestamp: March 04, 2022, 11:34:12 pm
content: Anyone ever deal with these ripoff artists?? Look and compare their prices for old military surplus C.R.T.'s and some N.O.S. from Tek and H.P. These clowns are insane with their prices. Most of their C.R.T.'s marked 'RARE' and selling for hundreds of dollars and two adds down on Ebay you'll see the same tube for under $35.00. I pity any unenlightened oscilloscope repairer who pays those moronic prices for 3RP1a's, 3FP7's, 5CP1's etc!!! I have seen some of his completely wrong rants about 'black plate' and 'gray plate' 6SN7's, 6SL7's and the whole family of 6L6 type tubes. I fear he has been dealing with the tubey audiophools for to long arguing the semantics of which brand and what color of 6L6 "Has the most open and transparent sound stage". His rare C.R.T.'s are anything but rare, and his 'collectible' radar tubes are pure military trash. Sorry for the rant, I know it's "Buyer Beware" I just feel sad that he thinks anyone would willingly pay those insane prices for what are still readily available tubes in quantity. And don't even get him started on who made which tubes and when!! What a putz.

author: m3vuv
author_rank: Super Contributor
timestamp: March 05, 2022, 06:49:37 am
content: theres a goon on ebay called radio spares ireland,seems everything he has on sale is "rare" and about 3x what its woth,get pissed off with the cretins!!
Batteries for older HP & Fluke instruments - Page 1
Forum section: electronics / repair

author: 1audio
author_rank: Frequent Contributor
timestamp: October 06, 2021, 07:02:42 pm
content: Some older instruments from both HP and Fluke used large sets of NiCad batteries. In some of the 1960's vintage HP instruments the batteries were part of the voltage regulation. Or, for example, the Fluke 540B running on battery is essential for isolation. However most of us use these instruments very occasionally so the battery shelf life (3 years?) becomes a real issue.I'm looking at making a battery for an HP 432A but I might just leave it out since its not necessary.Is there a best practice for dealing with these issues? I really don't want to buy 12V or 24V worth of C cell NiCads (or NIMH) for maybe six uses a year tops and have then deteriorate. I'm sure there are other instances of this as well.

author: bob91343
author_rank: Super Contributor
timestamp: October 07, 2021, 12:32:29 am
content: I am reminded of the time, several years ago, that I purchased a used Brother label maker that was defective because it worked only on batteries but not with the usual ac adapter wall wart.After using this for some time I decided to make it work with an ac adapter. I assumed the problem was in the closed circuit jack but that seemed okay. So I put a bench power supply on the unit and disccovered that it indeed worked fine via the jack, but required a narrow voltage range (too low or too high and it quit). I put in a little regulator and it's worked fine ever since.

author: aargee
author_rank: Frequent Contributor
timestamp: October 07, 2021, 01:27:58 am
content: Is it worthwhile designing something akin to a NiCd simulator?From the machine it looks like a NiCd but itself is powered by a NiMh or Lithium cell?The energy density of a set of LiPos could take the physical space along with a small circuit to provide the correct voltage/charge current.

author: james_s
author_rank: Super Contributor
timestamp: October 07, 2021, 05:00:14 am
content: There's a cheap way to get a bunch of NiCd or NiMH cells, buy a used power tool battery, or a cheap knockoff replacement. Roomba batteries are also readily available and have 10 NiMH cells.

author: 1audio
author_rank: Frequent Contributor
timestamp: October 09, 2021, 03:01:19 am
content: These older HP instruments I have need 20 Nicad cells. For the $32 power meter it is not a real issue since it works fine with no battery and I'm not sure if I need battery operation. However the HP 8062 sound level meter uses the batteries as part of the regulation. I may just install some big Zeners. The Fluke 540B is more of a challenge. I think replacing the rechargeable with some LI primary batteries may be the cleanest. The 10 year shelf life LI batteries make sense for a 1-2 times/year instrument.

author: james_s
author_rank: Super Contributor
timestamp: October 09, 2021, 03:35:16 am
content: You could also probably get away with using NiCd or NiMH AA cells, you can get cheap ones that don't cost much, and it's probably not too hard to drop the charge current enough to not cook them.