hybridfree/eevblog-posts huggingface dataset:
ESI 240C Electro Scientific Industries calibration and repair advice? - Page 1
Forum section: electronics / repair

author: NANOJOLTS
author_rank: Contributor
timestamp: June 17, 2025, 05:35:23 pm
content: ESI 240C Electro Scientific Industries calibration and repair advice?Hey all, anyone familiar with the repair and/or Calibration of the ESI 240C Kelvin ratio bridge?I happen to have accumulated 5 of the 240C's but only one (1) willcalibrate and function correctly. The other 4 exhibit a multitude of failures, The failures generally consist ofrunning out of adjustment/calilbration pot (hitting the limit) during the MULTIPLIER or RANGE calibrations.As to the one that can be calibrated and functions correctly, it's performance is outstanding and a inspiration torepair the others.I hope to use it as a troubleshooting reference for the resistance? measurement comparisions of the other 4. Trickywhen the differences are in +/- PPM range.I thought I would seek advice (tips tricks), before I attempt any repairs (soldering).The WW resistor values (Manganin/evanohm?) seem to have drifted in the +/- PPM range, so increasing or decreasingtheir values may prove difficult.Thanks NanovoltsHey all, anyone familiar with the repair and/or Calibration of the ESI 240C Kelvin ratio bridge?I happen to have accumulated 5 of the 240C's, but only one (1) will calibrate and function correctly.The other 4 exhibit a multitude of adjudtment failures, the failures generally consist ofrunning out of adjustment/calilbration pot (hitting the limit) during the MULTIPLIER or RANGE calibrations.The multiplier and deviation switchs have checked out good.As to the one that can be calibrated and functions correctly, it's performance is outstanding and a inspiration torepair the others.I hope to use it as a troubleshooting reference for the resistance? measurement comparisions of the other 4. Trickywhen the differences are in +/- PPM range.I thought I would seek advice (tips tricks), before I attempt any repairs (soldering).The WW resistor values (Manganin/evanohm?) seem to have drifted in the +/- PPM range, so increasing or decreasingtheir values may prove difficult.Thanks Nanovolts
ESP32 01S module overheating - Page 1
Forum section: electronics / repair

author: Jaunedeau
author_rank: Regular Contributor
timestamp: May 02, 2023, 06:56:43 am
content: Hi,I got an Atari 2600 dev cartridge (PlusCart v1.2). It uses an esp32 01s module to have internet access (to save high scores, download new version of games, ...)It never worked. The esp module smelled like super hot when I plugged the usb in. Yesterday I took off the ESP32-01S and notices than one component was really badly soldered : not really in place, and I could easyly remove it with my nail. I tested it with a DMM, it read 0ohms.Does someone know what this component is ? Is it normal it read 0R (in both directions) ?(yes, I understand it would be less expensive for me to order a new module than trying to learn things)Thanks,J.Edit : if my cheap DMM is right, on pad is 0R to 3.3V and the other to GND, that would logically make it a capacitor, maybe the module can worrk without it, I'll try.

author: wasedadoc
author_rank: Super Contributor
timestamp: May 02, 2023, 08:01:44 am
content: Yes, multilayer ceramic capacitors (MLCC) can go short circuit. If it is brown, probably a cap. Resistors usually black.

author: Jaunedeau
author_rank: Regular Contributor
timestamp: May 02, 2023, 09:53:37 am
content: it's white. There are brown caps on other places on the board.

author: stevelup
author_rank: Regular Contributor
timestamp: May 03, 2023, 02:47:03 pm
content: Remove the component and measure it out of circuit. If it's shorted, then you've found your problem.If it isn't, measure the pads on the board and you'll probably see the short is still there. If that's the case it means the ESP chip or voltage regulator is toast.
ESP32 WiFi-less - Page 1
Forum section: electronics / repair

author: PlainName
author_rank: Super Contributor
timestamp: October 20, 2021, 10:46:17 pm
content: Periodically I order a bunch of ESP32's and one or two of them will fail to connect to WiFi. Or connect but not make it through HDCP. Or get an IP address but be very slow accepting a connection. Usually I just send them back and make a mental note that a test jig for these would save a lot of dicking about. But today I brought up a system whose ESP32 is old enough that I can't recall where I got it from, so decided to take a look...The symptoms: After setup and kicking off WiFi in station mode, this is the end of the console log:Code:I (2167) wifi:new:<11,2>, old:<1,0>, ap:<255,255>, sta:<11,2>, prof:1I (2937) wifi:state: init -> auth (b0)I (2947) wifi:state: auth -> assoc (0)I (2977) wifi:state: assoc -> run (10)I (6077) wifi:state: run -> init (fc0)I (6077) wifi:new:<11,0>, old:<11,2>, ap:<255,255>, sta:<11,2>, prof:1I (6077) wifi:new:<11,0>, old:<11,0>, ap:<255,255>, sta:<11,2>, prof:1Lifted the tin lid to take a peek underneath and you can see from the photo what the issue is: the blue cap isn't soldered properly, and the grey one to the bottom isn't sure where 'up' is.I reflowed the blue cap which got me onto the network, but getting an IP address is still dodgy so the entire top really needs cleaning up and doing properly.Posted in case someone else has similar issues and can't find the fault in the code that causes it.

author: DC1MC
author_rank: Super Contributor
timestamp: October 21, 2021, 07:46:10 am
content: I'm using a lot of these ESP32 modules, until I've found my favorite seller I've encountered similar issues, between opening the shield, reworking the parts and soldering back the shield I have decided that discarding the whole module after pillaging the switches, LDO and the serial port chip is the best sollution to do, these are NEVER behaving at full specs, usually the sloppy work is paired with sloppy parts. So is not worth the time IMO, just get what could be salvaged, discard the rest and blacklist the seller.Cheers,DC1MC

author: PlainName
author_rank: Super Contributor
timestamp: October 21, 2021, 11:06:16 am
content: This is a Wroom, so nothing to save beyond those caps and flashI'm a bit surprised at how many fail on WiFi, though. Maybe that's the only thing that can be screwed up off-chip.
"Estrada 101" 4 channel soviet amplifier, 1st channel problems. - Page 1
Forum section: electronics / repair

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: March 01, 2021, 11:34:05 am
content: I'm having problems with my Estrada 101 amplifier, when I turn it on, sometimes the 1st channel protection light doesn't turn off, but after around 3 minutes it turns off. at first, I thought it was just a sticking relay, but then after around half an hour, I hear a pop and smell something burnt, the amplifier 2nd channel (which I was using at the time) was still working, none of the protection lights came on.so I turned it off, and the first thing I did was pull the 1st channel block/preamp out and look for anything there, and I saw the R39 resistor burnt, and nothing else.when looking at the schematic I would think that there is no way for the R39 resistor to be blown with the correctly sized fuse F2, the fuse would've just blown.maybe if pin 5 on the preamp block, if that gets shorted to ground maybe then, but I examined the rest of the amplifier and saw no place that it could be shorting.Maybe I should take it more apart and look closer at the first channel circuitrythe protection light problem followed the amplifier 1st channel, not the 1st channel preamp board, so the problem must be in the amplifieralso, all the fuses are original ones and the proper value.I've attached the schematics of the amp

author: Chris56000
author_rank: Frequent Contributor
timestamp: March 01, 2021, 06:48:46 pm
content: Hi!Is there any chance you could scan all the pages of the book you got that from please?There's a lot of useful additional information in Soviet manuals, including coil and transformer winding details, full voltage tables and layout diagrams, etc!This would assist me in rendering an English diagram for you!Chris Williams

author: serg-el
author_rank: Regular Contributor
timestamp: March 01, 2021, 10:49:07 pm
content: https://forum.cxem.net/applications/core/interface/file/attachment.php?id=448053http://rt20.mybb2.ru/viewtopic.php?f=5&t=50600http://offtop.ru/dustyattic/v1_720390_19_.phphttp://radionet.com.ru/forum/viewtopic.php?t=16494http://rt22.ru/viewtopic.php?f=5&t=55489Check and solder the connectors. Replace capacitors K50-6 (aluminum barrels). Check power supply and output transistors. The voltage map is in the circuit.

author: serg-el
author_rank: Regular Contributor
timestamp: March 02, 2021, 02:07:33 pm
content: So does the relay turn on / off? Is the protection lamp still on?R9 in the amplifier sets the output zero balance. R26 sets the quiescent current. It is imperative to adjust the balance, otherwise the protection will work.Check / replace C3 and C5 in the protection circuit.C3 power-on delay. C5 delay during protection operation.And without replacing electrolytic capacitors, repairs are pointless. They are 100% defective.
Eton / Lextronix E1  service manual wanted - Page 1
Forum section: electronics / repair

author: Jörg
author_rank: Regular Contributor
timestamp: August 23, 2020, 10:36:04 am
content: Hello.Can someone help me with the service manual for the Eton / Lextronix E1.My search in the usual places was unfortunately unsuccessful.Thanks Jörg

author: najrao
author_rank: Regular Contributor
timestamp: September 05, 2020, 10:47:32 am
content: At the time when the e1xm yahoo group operated, I had downloaded a 'service' manual, which I still have. This is fairly good, but lacks all schematics, limiting its helpfulness in tracing faults etc.I can send it to you at your private mail address. Call me at <najrao86@gmail.com>I have three of these e1's, and have bricked one of them while fault finding -- entirely because of a serious error in the service manual. More about this if interested.NAJR

author: Jörg
author_rank: Regular Contributor
timestamp: September 05, 2020, 11:29:13 am
content: Hi NAJR.Thanks for your offer to help. I will contact you. Of course, the schematics would be of greater help in troubleshooting.Do you know whether the circuit for signal processing from RF to LF is comparable to the satellite 800 Millenium?My E1 has a bug in the FM stereo stage.When I activate stereo, weak FM signals are noisy with the internal speaker.The right channel is missing on the audio outputs. With headphones and LineOut.With FM mono there is no noise and both audio channels have a signal.In addition, with the internal speaker, the FM audio is much quieter than e.g. AM or SSB on LW / MW / SW.I don't know. whether this is normal.I haven't opened the device yet.Therefore I don't know at the moment which integrated circuits in the E1 are used for the FM demodulation and the stereo decoder.Greeting. Joerg
EV Wallbox repair, Struggling with this one.  Please help - Page 1
Forum section: electronics / repair

author: Perrin21
author_rank: Regular Contributor
timestamp: October 08, 2019, 12:25:30 pm
content: Hi, i have been trying to repair my Chargemaster wallbox as it has recently started exhibiting a strange fault. When i plug it into the car the relays engage and it tries to charge the car but after a second or two it disconnects and tries again, this process repeats until the power to the charger is turned off or the car is disconnected. The charger displays no fault code on its main display when its powered up and disconnected and displays the orange light as normal.I have had it suggested that it could be the relays at fault so i have replaced all 3 relays with new ones, however the charger still has the exact same fault. Can anyone think of anything else i should be checking? I have checked continuity all around the relays and all seems as it should be. I have also checked the electrolytic capacitors and their ESR is good. Do you have any suggestions? All help gratefully received. I am unable to locate a service manual so if anyone recognises the board as a clone of another, please let me know.I also get continuity in both directions on Q7 Triac but im starting to wonder if this is normal behaviour for a Triac anyway.Here are some pics of the front and back of the main board.

author: Perrin21
author_rank: Regular Contributor
timestamp: October 08, 2019, 12:44:07 pm
content: really strangely i have just tried it again and i managed to get it to charge for 30 seconds before it turned itself back off. Once it turns itself off it keeps trying and you hear the relay switching back and forth as it tries but only the first time lasts upto 30 seconds.

author: fzabkar
author_rank: Super Contributor
timestamp: October 09, 2019, 01:42:07 am
content: www.completepowerelectronics.com/how-to-test-triac-with-multimeter/

author: cozza
author_rank: Regular Contributor
timestamp: October 09, 2019, 01:46:24 am
content: U28, the Power Integrations simple switcher TNY27(6?) - I can't quite make it out.I've seen these fail in power supplies with the symptoms you describe. They run for a bit and stop.This could be cause if the all the low voltage supplies disappear when it drops out (no LEDS etc)Check ESR of the 47uF Cap as well.

author: Perrin21
author_rank: Regular Contributor
timestamp: October 09, 2019, 12:30:44 pm
content: excellent suggestion, i will take a look and feed back.
EVGA 750W G2 80+ Gold -> X2 Cap Burnt - Page 1
Forum section: electronics / repair

author: foetusmachine
author_rank: Contributor
timestamp: February 23, 2024, 09:00:56 pm
content: Hi all,Might not be a query specific to the PSU itself, but detail provided, just in case.My PSU virtually caught fire last night. Thankfully I could smell magic smoke, just before I went to bed. Magic smoke is not a common thing where I live, and if I can smell it, I can be 90%+ sure it's something to do with me. Taking the PC outside, I dismantled the PSU and found what I think is the culprit:The x2 cap had burnt (burned?) through both side and released the magic and left its white residue everyehere.A few key points to note:1. The PSU has a power saving mode where its internal fan is switched off until a certain load is reached. I had this activated.2. The PSU is secondhand. I have no idea of its history.3. Since I've been using it, it's been plugged in via a UPS.4. I pulled the plug before the fuse blew.5. I was unable to determine the actual value of the cap and have since found a 0.47uf X2 salvaged one in my drawers and replaced it.6. I'm now back using the PC with the PSU's fan always on.Questions:Is this a expected failure mode of X2 caps?The failed X2 cap pin spacing is ~15mm, but the PSU PCB has optional through holes to also accommodate a larger ~22mm X2 cap. Is there any benefit in me installing a physically larger cap?Is there any benefit in using a higher rated cap (X1)?Note: I will continue to use the PC behind a UPS.Any input here would be great Thank you for listening to this many of my words!Replacing the PSU with a new, warrantable unit - yes, thank you.

author: fzabkar
author_rank: Super Contributor
timestamp: February 23, 2024, 09:08:13 pm
content: I would put it down to bad luck, although there have been some notable exceptions.https://hackaday.com/2023/04/01/why-do-rifa-capacitors-fail/
(done) Evil blue ALPS pot is noisy - Page 1
Forum section: electronics / repair

author: Haenk
author_rank: Super Contributor
timestamp: January 06, 2024, 08:39:15 am
content: My recent purchase did come with a very noisy pot.Unfortunately, it seems like these are now Unobtainium. (X3 with A curve; X3 is not even listed by ALPs any more)So I have only few options:0) just wiggle it around1) Open and clean2) use X4 and cut legs of the 4th pot, there is enough space on the PCB; however A curve seems unavailable, too3) use X4 with B curve4) bodge in a different pot5) recreate a X3 pot by combining segments from donor pots with the original axle; is that even possible?I would like to avoid 3) and 4) and 5).So that leaves 2) - if I could source an A curve specimen, or the cleaning option. Any suggestions for "what to use"? I read about carefully splitting the parts and to use the small gap. Flood? A complete disassembly is probably not possible by the looks.Any suggestions are welcome. (For now, I'm probably trying to simply trun the pot for half an hour or so, that machine probably sat for a decade or two. Then using some TESLANOL OSZILLIN, and turn again...)

author: David_AVD
author_rank: Super Contributor
timestamp: January 06, 2024, 08:49:55 am
content: Looks like it comes apart. Open and clean would be my choice. Even if you just open it up enough to get some suitable spray into it.

author: Haenk
author_rank: Super Contributor
timestamp: January 06, 2024, 11:44:28 am
content: So after about 200 turns of the pot, the issue is now fixed. Probably just two decades of corrosion. Will add some pot spray later.For your viewing pleasure, this is it (made by Philips/Studer, the first standalone CD recorder, which cost me a whopping 50 EUR...):
Exact Electronics 500 Series Waveform Generator Instruction/Service Manual - Page 1
Forum section: electronics / repair

author: telans
author_rank: Newbie
timestamp: February 18, 2024, 09:48:36 am
content: Hi all,I recently got my hands on an old Exact Electronics 505B waveform/function generator with the instruction/service manual. I haven't found the manual for my unit available anywhere online so I thought I would share it here. Hopefully it might come in handy for someone in the future. There's a version of the manual for serial numbers above #2500 on eBay, whereas my unit is #2362.I've had to split and compress the majority of the pages in order to fit within the attachment limit. If anyone wants the 600dpi version let me know (~100MiB). I've run OCR on all the pages which from a quick view works well.

author: telans
author_rank: Newbie
timestamp: February 18, 2024, 09:49:15 am
content: Section 3: Operating Instructions

author: telans
author_rank: Newbie
timestamp: February 18, 2024, 09:50:33 am
content: Section 4: Circuit DescriptionSection 5: Calibration

author: telans
author_rank: Newbie
timestamp: February 18, 2024, 09:51:40 am
content: Section 6: Parts List

author: telans
author_rank: Newbie
timestamp: February 18, 2024, 09:52:54 am
content: Section 7: Circuit Diagrams

author: telans
author_rank: Newbie
timestamp: February 18, 2024, 09:53:33 am
content: Section 8-9: Representatives, Distributors, Addenda

author: telans
author_rank: Newbie
timestamp: February 18, 2024, 09:55:20 am
content: Well it seems whatever settings I used with Ghostscript stripped the OCR. That's a shame.
Exact Electronics Function Generator 506 schematics - Page 1
Forum section: electronics / repair

author: klausn@live.com
author_rank: Newbie
timestamp: November 08, 2021, 08:34:57 am
content: HelloDoes anyone happen to have the service manual or schematics for this old (1970's?) function generator?(Exact Electronics Function Generator 506)It's lighting up nicely, but the outputs are dead. When measuring the circuit I see the transformer working, but 0 volts on the pcb entry points labeled + and - 12. I unscrewed the big smoothing caps, and they also seem to be working fine - though their capacitance is larger than it says on the component (3900 instead of 2700 uF). I'm thinking maybe a burned out diode is shortening the regulated power outputs to ground?Either way the schematics would be a huge helpCheersKlaus

author: klausn@live.com
author_rank: Newbie
timestamp: November 18, 2021, 09:52:03 pm
content: alright - found the culprit: a darlington transistor connected to the negative power rail was broken - literaly. It was fastened to the back panel for cooling and the screw had been tightened too hard breaking the transistor in 3 parts.replaced it and also some tantals that were busted and now it runs as if brand new.put it to some good (and alternative) use here:https://youtu.be/7J_nbIg4wQ0enjoy
Excelvan Capacitor Meter M6013 Repair - Page 1
Forum section: electronics / repair

author: electrofix
author_rank: Contributor
timestamp: July 17, 2023, 02:03:04 pm
content: Hello and thank you for reading my post. I am starting the repair of an Excelvan Capacitor Meter M6013. The issue is that it works from the plug-in microusb but does not work from the batteries. It was working fine and all of a sudden it stopped working from the batteries. I plugged in the microusb cable and it works fine. Also, if I unplug the microusb cable with the batteries (brand new batteries, fully tested) it turns right off. I am going to open it up and see if the wires going from the batteries to the board have been broken. I will be posting pictures of the progress.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 17, 2023, 02:32:23 pm
content: the best would be to identify the parts ... ive seen some m6013 teardown, but havent seen any dedicated parts for the batteryprovide closer pictures of the components

author: electrofix
author_rank: Contributor
timestamp: July 17, 2023, 02:36:36 pm
content: Thank you coromonadalix.I have opened it and completed the first test.

author: electrofix
author_rank: Contributor
timestamp: July 17, 2023, 02:37:24 pm
content: More Meter Pictures:

author: electrofix
author_rank: Contributor
timestamp: July 17, 2023, 02:38:27 pm
content: Board Pictures:

author: electrofix
author_rank: Contributor
timestamp: July 17, 2023, 02:39:31 pm
content: More Board Pictures

author: electrofix
author_rank: Contributor
timestamp: July 17, 2023, 02:53:08 pm
content: I noticed the battery box wires are soldered with red wire as negative and black wire as positive going into the board.But it still gives Positive 3V going into the board as pictured.

author: electrofix
author_rank: Contributor
timestamp: July 17, 2023, 04:22:14 pm
content: I am guessing to start testing "Q6" on the board? Does anyone know what it is and how to test it?
Exchange broken potentiometer of a dimmable halogen lamp - Page 1
Forum section: electronics / repair

author: T_guttata
author_rank: Regular Contributor
timestamp: April 07, 2024, 07:00:20 pm
content: Dear all,I have a special lamp (medical equipment) from 1994 with a broken potentiometer. I need to find a sparepart for that, but since I'm not very familiar with the circuitry I hoped someone could help me.The halogen lamp uses an electronic transformer with 22.8V AC output, but I could not find any schematic. Therefore, I don't know exactly what the potentiometer does and how I can find a spare part.I have made a few pictures. Based on those pictures, can anyone point me in the right direction?Thanks!

author: inse
author_rank: Super Contributor
timestamp: April 08, 2024, 01:38:00 pm
content: Look carefully if the resistance value is noted somewhere on the potentiometer or try to measure the maximum resistance.Then you need to find a model with enclosed switch suitable for 230V.If you don’t succeed, the only chance would be to have a separate switch and potentiometer.
EXFO Max-715B OTDR: Won't Charge Internal Lithium Battery - Page 1
Forum section: electronics / repair

author: MrMosfet
author_rank: Newbie
timestamp: January 08, 2022, 01:29:47 am
content: Have an EXFO OTDR that no longer wants to charge the internal battery LiPo battery. All other features/functionality work, if powered from the 9V-18VDC input jack although a battery is need for it to bootup. When on the red LED low battery indicator blinks red indicating a low state of charge... I've been charging the battery manually and have load tested with 100mA->500mA and the output voltage is steady at 3.9VDCControl board output to the battery ~2.6VDC, I've checked it with input voltages ranging from 9-15VDC and tried sweeping a the thermistor terminal resistance from 1k to 25k and don't see any changes (Batteries thermistor reads ~10k at 75 deg F). Not the most proficient with board level repairs but can usually poke my way through with a schematic, challenge I'm having is identifying the charge controller with limited success googling most of the chips.I'm hoping somebody might be able to point out chip most likely related to the LiPo battery charging so that I focus additional research into identifying it

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 18, 2022, 09:24:19 pm
content: "Control board output to the battery ~2.6VDC"Is it easy to find T there, to meter sec. winding output and to know that's value or 3.9 V it is?

author: m3vuv
author_rank: Super Contributor
timestamp: January 19, 2022, 11:44:35 am
content: Can you not bodge on a TP4056 ,and feed it with a 5v supply and let that charge it?
"Expensive" PC keyboard - ERROR 43 (software solution impossible) - Page 1
Forum section: electronics / repair

author: Kikerumbo
author_rank: Newbie
timestamp: June 06, 2022, 11:57:46 am
content: Greetings,I've been fighting with this keyboard for weeks and as a last resort I'll try to dive into the beast "guts", with your help I hope. I wouldn't try to repair it if it wasn't because it costed me +200€.The issue is that not one of the 7 different PCs I tried recognize the keyboard. Always an ERROR 43 code is shown. Keyboard LEDs turn on, but it doesn't work. I've already done everything I can "software side". No drivers, different drivers, specific software from the manufacturer. Same result. The manufacturer, ROCCAT, has an utility for flashing firmware but is doesn't even show the keyboard when I try to use it.So... now I'm here.Would anyone know where to go from here? I see various SMD, like the ARM processor, the CMOS and 3 others that when I search for the code number, nothing is shown. Swapping the CMOS is doable (with my low level of soldering skills) and cheap (around 2€). But I'm "alone in the dark" since I don't know if the CMOS is the issue or how to test it.I know wiring is ok, connectors too (USB and the inner ones) because I did a continuity test with a multimeter.Pictures show the "innards".Thanks in advance to anyone willing to help.Have a good day!

author: fable
author_rank: Regular Contributor
timestamp: June 11, 2022, 09:32:04 pm
content: Hi I'll try to help...first you need to see if there are some components between USB data lines and MCU if there is not the most probably MCU is damaged. However if there are some, those components if faulty can block communication.

author: fzabkar
author_rank: Super Contributor
timestamp: June 11, 2022, 10:47:51 pm
content: Check the continuity of the L2 choke near the USB connector.Also check the outputs of the LDO regulators (U1 & U4).AN32181B, Panasonic, 12 x 12 Dots Matrix LED Driver LSI, 5V, QFN-28:http://pdf.datasheetcatalog.com/datasheets/panasonic/AN32181B.pdfMX25L1606E, Macronix, 16M-bit [x 1 / x 2] CMOS serial flash, 2.7V - 3.6V, SOP-8L:https://datasheet.octopart.com/MX25L1606EM1I-12G-Macronix-datasheet-12510710.pdfLPC1752FBD80, NXP, Cortex-M3 microcontroller, 64KB flash, 3.3V, LQFP80:https://www.nxp.com/docs/en/data-sheet/LPC1759_58_56_54_52_51.pdfUR133AL, UTC, 300/500mA LOW DROPOUT LINEAR VOLTAGE REGULATOR, SOT-89:http://www.utc-ic.com/uploadfile/2011/0902/20110902012023486.pdf

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 11, 2022, 11:43:14 pm
content: Using another keyboard, run "sudo dmesg -c", then plug in the problem keyboard and run "sudo dmesg" after a few seconds. That will tell if it's it's trying to communicate on USB at all.
Extech 380820 AC Power Source repair - Page 1
Forum section: electronics / repair

author: gamedog
author_rank: Newbie
timestamp: June 07, 2022, 01:56:00 pm
content: Hi everyone!I have an Extech 380820 AC Power Source in which the EEPROM Serial IC U10 24LC64I chip on control processor board is burned out. I wrote to Extech support, but they denied saying that this product is discontinued. Maybe one of the enthusiasts who has such a power source will be able to read the firmware (Dump) from the U10 chip and put it here? I'll be very thankful. There is practically no place to find this firmware.Thanks in advance.

author: m k
author_rank: Super Contributor
timestamp: June 13, 2022, 10:15:31 am
content: Are you sure it's a firmware ROM?It's only 64k bits.Is the machine totally mute?Manual indicates that flir.com is the support.No idea what that really means.

author: strawberry
author_rank: Super Contributor
timestamp: June 13, 2022, 11:25:35 am
content: it is most likely to store cal data and settingsit is possible that MCU code asks/needs functional EEPROM with something special (startup signature..) stored on it

author: gamedog
author_rank: Newbie
timestamp: April 26, 2023, 08:35:30 pm
content: Hello!I replaced the 3.3V linear voltage regulator chip and soldered a new U10 chip without firmware. The device turns on, but the LCD screen is empty. Nevertheless, the firmware of the device is most likely in the U10.
Extech 382280 PIC fW - Page 1
Forum section: electronics / repair

author: mpozna
author_rank: Contributor
timestamp: July 28, 2020, 06:49:19 pm
content: Hi all,I have an Extech 382280 with the PIC18C452 faulty. Is there anyone here or anywhere that has the FW? Or the pinout/signals from the control pcb to switch pcb - could work some controller using tha. Never seen it working so can not work pinout/signals.Thank you,Marius
Extech EX830 Clamp on meter - Page 1
Forum section: electronics / repair

author: jonstull829
author_rank: Newbie
timestamp: November 11, 2021, 04:39:34 pm
content: Any advise on how (if possible) to adjust the Resistance and Capacitance functions on this clamp on meter?Needed for calibration purposes...Have found links to calibration procedures, but none have Resistance in them.
Extech EX655 - Resistance metering failure - Page 1
Forum section: electronics / repair

author: Tantratron
author_rank: Frequent Contributor
timestamp: November 22, 2023, 11:23:42 am
content: Hello, I've purchased back in 2016 an Extech EX655 true rms AC/DC Clamp Meter which worked always fine.However for a few months, the resistance measurement has partial failure where it keeps oscillating (0.L and high MegOhm). If I remove the 9V battery then reconnect, it might work the first time but then will go nuts.All other functions (ampmeter, voltmeter, frequency, NCV...) still work fine.I see on our forum that few recalls were done for these EX serie of DMM but not clear if my failure is related.Any advices or suggestions would be much appreciated.Thank you, Albert
Extra 7905 regulator in Aten KH1516i KVM switch - why? - Page 1
Forum section: electronics / repair

author: hanakp
author_rank: Regular Contributor
timestamp: December 20, 2019, 01:57:41 pm
content: About a year ago, a system admin in my workplace asked me to fix old Aten KH1516i 16-input VGA KVM switch. It repeatedly rebooted and beeped, some LEDs blinked during the process. It was the classic problem, bad primary-side caps in its power supply.Two months ago a different problem emerged, the switch didn't route video from any slave ports, but keyboard and mouse signals worked fine. At first I tought the master port was dead, but it wasn't the case, because it displayed OSD and service menu as it should. But it showed a black screen from all slave ports. So I assumed the analogue switches for the VGA signals must not work properly. I couldn't find any service manual, but I assumed it must be some power problem. The power supply has 3 output voltages: standalone +5 V for digital circuits and symmetrical +-5 V for analog ones. The +5 analog voltage was fed to the main board directly, but the -5 V one (black wire in the first photo) went through a 7905 regulator, which was "guerrila-style" mounted on one of the screw posts. I measured about -4.2 V at its output. When I shorted it, the switch immediately started to work. So as a fix, I disconnected the regulator completely and made a bypass wire that I installed directly into the original connectors (3,96 mm pitch Molex KK series). It has been running for two months now with no apparent ill effects.The reason why I'm writing is that I don't understand these things:1. Why was the regulator there in the first place? In essence, it just worked as a really expensive diode, there was around 0.8 V drop on it. And it wasn't faulty, either - when I connected its input to -9 V external PSU, -5 V appeared on its output and the switch started to work.2. Why the switch worked fine for 12+ years, but then suddenly stopped? Could something change on 7905 chip over time when it's not working in the active region? Electromigration, perhaps?The only explanation I can think of is that some PSUs produced higher negative voltages than they should and Aten added the 7905 as a precaution/protection.

author: PKTKS
author_rank: Super Contributor
timestamp: December 20, 2019, 02:15:23 pm
content: apparently you answered yourself3pin 7xxx or equivalents are meant to 3V differential minimumfor proper regulationIf for some weird reason you have less than that ..the supply pin of the regulator is bad.Your problem is there - and is not the regulator.for the purists the quiescent dropout is 2Vand 2.5 should be enough although poorly regulated.Paul
Extract data from Galaxy S2 eMMC - Page 1
Forum section: electronics / repair

author: sverzijl
author_rank: Contributor
timestamp: May 10, 2020, 06:12:13 am
content: Hi all,Many years ago I went travelling to Europe. One of my brilliant ideas at the time was to use those Wifi enabled SD-Cards on my camera which backed up your photos to your phone as you took them.When I returned home my phone died and I discovered that it had stored the photos to the internal memory. I put the phone away to deal with lately as I couldn't find anyone who would do more than replace the circuit board - which defeats the purpose...Now, many years later, I decided to start investigating how to get the photos off. Conceptually, through research, I know how to get the data off it by removing the chip (BGA) - however the process seems high risk without the right skill or equipment. I see lots of talk of 'popping'.I have also seen people soldering thin wires onto the PCB itself and accessing the data with the chip in place, however, I can't see a way to work out where to solder the wires to (independent of skill) - the schematics don't show how its wired up on the board.So my question is - where do I go from here? Does anyone have any further information I can follow? Is there someone I can pay to do it or at least part of the process?

author: aqibi2000
author_rank: Regular Contributor
timestamp: May 10, 2020, 01:29:54 pm
content: I can remove the eMMC for you without popcorning.Have the full works with regards to BGA rework station equipment
EZ Battery Reconditioning - Can someone confirm this is total scam? - Page 1
Forum section: electronics / repair

author: Tegra
author_rank: Newbie
timestamp: September 05, 2019, 07:37:46 pm
content: Is "EZ Battery Reconditioning" the biggest scam there is?There is a flood of comments from ones who said they thought it was a scam and then bought the book and then "their life changed".Would like to know if the "book" has any real technology in it or if it is a fluffy "batteries for dummies" book?There must be someone who has shared the pdf so this can be reviewed?(I think we all owe "the internet" some time in quashing technical junk like this appears to be.)Tom (now afraid to use my name)

author: Stray Electron
author_rank: Super Contributor
timestamp: September 05, 2019, 09:27:28 pm
content: Quote from: Tegra on September 05, 2019, 07:37:46 pm"their life changed" probably just means that they're now just that much poorer. IMO when suchvaguestatements are made, it's usually for a reason.Even IF this reconditioning technique actually worked, I can't imagine that it would make someone's life change.

author: fzabkar
author_rank: Super Contributor
timestamp: September 05, 2019, 11:08:47 pm
content: Maybe they got a few more years out of their Pacemaker.

author: Leighcrx
author_rank: Newbie
timestamp: September 06, 2019, 12:51:13 pm
content: If you do not value your time then waste 20 minutes of it, watch the marketing video. I was impressed at how long they dragged it out for and the utter BS they claimed.Then the its worth $300 but we will sell it to you for not $200, not $100 not $50 but special price of $29.99

author: Black Phoenix
author_rank: Super Contributor
timestamp: November 27, 2019, 01:32:33 pm
content: Quote from: mario.fernandez on November 27, 2019, 01:04:49 pmFunny that the link is reported by uBlock on Firefox - Found in: Malvertising filter list by Disconnect • hpHosts’ Ad and tracking serversAnd yes it's a scam... Specially with all the popups when leaving the page and whatever. A good product, that really works and it's not a scam doesn't need to rely in this kind of design when making a website.

author: madires
author_rank: Super Contributor
timestamp: November 27, 2019, 02:02:56 pm
content: ... especially when the very first post of a new user is "no scam, works great".
F-15 Strike Eagle arcade game - Page 1
Forum section: electronics / repair

author: Phil Bennett
author_rank: Newbie
timestamp: September 12, 2019, 02:02:47 am
content: I repair arcade PCBs as a hobby and recently fixed this game that I acquired last year. This was certainly one of the more challenging repairs I've undertaken. Hopefully some of you will enjoy reading this long, rambling repair write-up on this somewhat rare and unusual game:https://philwip.com/2019/09/11/pcb-repair-f-15-strike-eagle/

author: xrunner
author_rank: Super Contributor
timestamp: September 12, 2019, 02:05:28 am
content: Most impressive work!

author: Zucca
author_rank: Unknown
timestamp: September 12, 2019, 10:24:36 am
content: cool

author: shakalnokturn
author_rank: Super Contributor
timestamp: September 12, 2019, 08:03:33 pm
content: Any explanation on why you'd have several bad PLD's?I like the AMD and Kyocera logo together on the Am29C323, what's the story behind that?

author: Kjelt
author_rank: Super Contributor
timestamp: September 12, 2019, 09:38:09 pm
content: Wow great job and perceverence, looks like the Gals are loosing their programming charge just as eproms. They should have used Pal chips however they were not build to last 30+ years I guess

author: Phil Bennett
author_rank: Newbie
timestamp: September 12, 2019, 10:06:58 pm
content: Quote from: shakalnokturn on September 12, 2019, 08:03:33 pmI'm not sure exactly why the GALs had failed. They were Lattice parts manufactured around 1990, were clocked at 16MHz and had been operating at 5.25V until I decreased the PSU output to 5.0V. Bitrot would have been a reasonable explanation but these parts appear to be electrically damaged; my device programmer wouldn't even attempt to read them so I can't even erase them. I've observed similar failures with other hardware/GALs.I never noticed the Kyocera logos before; well spotted. My guess is that Kyocera manufactured the ceramic packages used by AMD's ICs.

author: Whales
author_rank: Super Contributor
timestamp: September 12, 2019, 11:14:23 pm
content: Hmm, voltage addiction? Try reading/erasing/etc them with VCC=5.3V or a bit more?Make sure to measure and/or limit current. They might seem dead and (unlike the working GALs) you might feel free to experiment with them a bit more, but it's worth trying to keep them in one piece for future tests you might come up with.Great post by the wayI'm very jealous however -- you have (A) socketed chips, (B) spare parts and (C) an in-built per-build debug interface. I don't think I'm every going to be able to repair my dreamcast.

author: wraper
author_rank: Unknown
timestamp: September 12, 2019, 11:21:01 pm
content: Quote from: shakalnokturn on September 12, 2019, 08:03:33 pmLikely has something to do with ceramic package.https://asia.kyocera.com/products/semiconductor/
F117 fatal error - Page 1
Forum section: electronics / repair

author: najrao
author_rank: Regular Contributor
timestamp: May 13, 2021, 12:33:13 pm
content: Perhaps I should not have directly resuscitated my old problem after 4 years. Nobody scrolled down to read my last message.I do not know how to reference back to this topic.I repeat just my last:Refers back to Sep 2017, pls forgive me.My F117 remains bricked, I fished it out to see again.New findings:1. Input terminal shows 18 to 20M* in all V positions, not 10 or 11. Auto-V Lo-Z shows 3.2K. Protection elements test OK.2. Ohms, Continuity, and Diode modes show zero V at input terminal. Any of my other DMM's show a source voltage, e.g., F112 puts out 2.5V for the diode position, and 650mV for Ohms (ranging megohms).There is but one dc reg ic on the board (TPS77050), and it puts out 5V. I do not know how the resistance modes work, nor how the 3.15V for the MSP is derived.Surely, my wise friends should make something of this!*>80M , i.e., OL when checking later; not consistent
F60SA60DS - Dual Series Connection Fast Recovery Rectifiers - Replacement - Page 1
Forum section: electronics / repair

author: 2X
author_rank: Frequent Contributor
timestamp: September 25, 2023, 04:58:10 pm
content: Hello, I have a power supply that it has shorted the "F60SA60DS" diode rectifier. I can't find any replacement of this connection "Reverse Doubler Polarity" (Series Tandem Polarity) in sites like mouser electronics, digykey etc (only in aliexpress). I wonder if I could try to put two seperate diodes (each at 8A/600V) in series like the "F60SA60DS" or inside the semiconductor it is not only just a two diodes in series (at least only to test the power supply if it works and then to put the original diode "F60SA60DS"?https://www.semiee.com/file/backup2/THINKISEMI-F60SA60DS.pdf

author: jwet
author_rank: Frequent Contributor
timestamp: September 26, 2023, 01:15:40 am
content: Using two is no problem. Find one with same or better specs- those are very high current pretty fast diodes. Don't forget that diodes that run lots of current and drop voltage, dissipate real power. These parts can drop over 2v and conduct 8A, that's 16W when conducting. I would keep the two parts close together, if you're really concerned, you could heat shrink the together so they'll track like the dual but its likely not necessary.

author: 2X
author_rank: Frequent Contributor
timestamp: September 26, 2023, 09:03:09 pm
content: Turbo 2 ultrafast high voltage rectifierSTTH8R06FPhttps://eu.mouser.com/ProductDetail/STMicroelectronics/STTH8R06FP?qs=sMZUW2WomJKVGLEPLyLe%252Bw%3D%3DAlso, I found a replacementSTPSC8TH13TIhttps://eu.mouser.com/ProductDetail/STMicroelectronics/STPSC8TH13TI?qs=DqCdCwOw4%2F7UoxjXux7BQQ%3D%3D

author: u666sa
author_rank: Frequent Contributor
timestamp: September 26, 2023, 10:25:50 pm
content: I would just get anything that is locally available in this package, so long as it is 600 volts or above, and 8 amps per diode or 16 watts per package or more.Then I'd do leg switcheroo, they are long on new diodes, so you can bend them whichever way you want.And call it a day, Bob is your uncle!
FA-2 26GHz frequency counter prescaler. Need help with IC recognition - Page 1
Forum section: electronics / repair

author: Aleksandrs_S
author_rank: Newbie
timestamp: November 19, 2023, 09:09:24 pm
content: Hello!I bought FA-2 Frequency counter (26.5Ghz version) and it worked fine up to 24GHzAfter a few months it stopped working (the reason is not clear to me, maybe ESD), but the input RF power was definitely not exceeded.I bought another one of the same device (again Eur 420)a few months later the situation repeated itself with new deviceafter a short investigation I found out that the input prescaler is damagedI set jumper between prescaler input and output. Freq on display is multiplied by 8 of actual frequency.what i know about this ICMax freq - 26.5Ghz Min 200 Mhz (maybe lower, but not tested)Power supply voltage - +3.3VDiff Input and Diff outputAll other pins and pad connected to GNGPlease help recognize the prescaler chip. Marking code S004 SSZD6or suggest alternatives (I haven't found a suitable alternative in stores. Or a different supply voltage or a different frequency range or a different pinout)Thanks!

author: hugen
author_rank: Newbie
timestamp: February 18, 2024, 03:22:36 am
content: If you can modify pin14 to VCC and provide 5V VCC, you can use the HMC494 replacement.

author: fzabkar
author_rank: Super Contributor
timestamp: February 18, 2024, 04:51:22 am
content: FWIW, "C74" can operate at 5V.https://ww1.microchip.com/downloads/en/devicedoc/21828f.pdf

author: BigBoss
author_rank: Regular Contributor
timestamp: February 18, 2024, 08:33:25 am
content: It's probably thishttps://www.analog.com/en/products/hmc862a.html

author: Aleksandrs_S
author_rank: Newbie
timestamp: August 31, 2024, 08:39:35 pm
content: Quote from: hugen on February 18, 2024, 03:22:36 amThis thread hasn't had any replies in a while, so I just decided to try HMC494I bought 2 chips from Farnell in November 2023 and installed them on December 12th.The 3.3 to 5V boost converter is mounted on the back of the board. The device has been working since December 2023 without any issues.The upper frequency limit is now 19 GHz instead of 26.5 GHz. But this is better than a device with a broken channel.So I followed your advice before it appeared.Thank you very much for your help.
Help: FA5331P Buck boost PFC can't run at 100Vdc input? - Page 1
Forum section: electronics / repair

author: CafeNovember
author_rank: Newbie
timestamp: February 23, 2021, 05:49:39 pm
content: Hello dear forumI am having 1 active PFC circuit as photo. Now I want it to work in the 95Vdc -> 130Vdc voltage range.According to its original design it can work from 85 * 1.4142 = 120Vdc to 373Vdc.Can anybody tell me how I need to make modifications to make it work and stable with such low input voltage.Thank you and very interestedCafeNovember

author: fzabkar
author_rank: Super Contributor
timestamp: February 24, 2021, 01:06:51 am
content: From the datasheet ..."Design the circuit to keep the peak voltage at pin 3  within a range from 0.65V to 2V for FA5331"Vpeak(min) = 0.65V x (240K + 240K + 2.7K) / 2.7K = 116VR6 = 480K / (Vp/0.65 - 1)If Vp = 100V, then R6 = 3.14K.I would make sure that your PWM duty cycle is not maxed out at max load.

author: CafeNovember
author_rank: Newbie
timestamp: February 24, 2021, 03:44:49 am
content: Dear Mr. fzabkarThank you for your help!I will try tuning the R6 and reply soon.Wish you a nice day.CafeNovember.

author: CafeNovember
author_rank: Newbie
timestamp: February 25, 2021, 05:23:31 pm
content: I have measured voltage values on IC FA5531 at voltage values in operating range and below threshold. Including the situation I changed the resistor value of the bridge for the voltage divider for pin 3- VDET.The final measurement in the table, when R7-8 was changed, VDET = 0.76V> 0.65V but Vo = 96.3V showed that the Boost circuit was not running.I have suspected pin 12 (On / OFF) is overridden by the connection to IC M51957B. I attached datasheet M51957B, then I will go and re-draw the 12 pin circuit connected to it so you can help me find the problem.

author: fzabkar
author_rank: Super Contributor
timestamp: February 25, 2021, 07:09:07 pm
content: The application circuit for the other IC also has a potential divider on the input (R1/R2).Would it be safe to disconnect ON/OFF for testing purposes?

author: CafeNovember
author_rank: Newbie
timestamp: February 25, 2021, 10:14:49 pm
content: I adjusted to Vpin2 = 1.9V. R7-8 = 430K. R6 = 3K. Then the circuit worked at Vin = 100Vdc. Vout = 366V but appears a little noise ~ 1.3V.I started to try loading 3A-12A and 21A to see what happens.

author: CafeNovember
author_rank: Newbie
timestamp: February 26, 2021, 12:50:58 am
content: The PFC circuit in this context is a PFC boost circuit for a switching power supply circuit (SMPS) 24V / 21A output Bucket behind. They are designed by manufacturers to work together.Can any one tell me what will happen if I lower the Vout voltage of the PFC circuit lower? And if so, how low is SMPS circuit still working properly?In this case I reduce Vin three times, For 1 bridge to divide the voltage for the parts such as voltage feedback, overvoltage protection feedback ... should I reduce the high side resistance (R7-8 440kOhm) or Will increasing low side resistance (R6 2k7) be better?Someone passing by can help me with some clarification!Thanks & Brgds