hybridfree/eevblog-posts huggingface dataset:
DKN AM-E exercise bike: Fails to wake on button press - requires power cycle - Page 1
Forum section: electronics / repair

author: mahi
author_rank: Regular Contributor
timestamp: December 17, 2024, 05:37:21 pm
content: A friend has a DKN Technology AM-E exercise bike (hometrainer) that developed a strange issue: When it has not been used for a while (anywhere between hours to days), it no longer wakes by pressing buttons or pedaling. Simply unplugging power for a brief moment fixes the issue, but then the previously used program and settings are lost.I took a look at the board, but did not see obvious signs of damage. I removed and checked capacity and ESR of the 6 electrolytic capacitors (4x Chengx 100µF/25V, 1x Chengx 220µF/25V and 1x Fengle bipolar 100µF/25V). All were reasonable. Nevertheless, I replaced the unipolar ones with new Rubicon capacitors. That did not fix the issue.All buttons and the pedal sensor are connected directly to the Fujitsu MB95F378E microcontroller with external pull-up resistors and ground the microcontroller input when pressed/activated.When the bike does not receive input for a couple of minutes, it goes to sleep. Pedaling or pressing any button wakes the unit. If you put a microcontroller to sleep, you can wake it with interrupts. However, apart from the pedal sensor, none of the buttons are connected to an interrupt pin. So, I'm not even sure the microcontroller enters sleep mode. It may simply turn off the display.I'm pretty sure it's not a problem with the power supplies on the board. When the problem occurs, the 3.3V power rail is present on the microcontroller. When I press one of the buttons, I see the appropriate pin on the microcontroller go from 3.3V to 0V, but there's no reaction. If however, I briefly pull the RST (reset) pin to ground, the microcontroller restarts and everything works normally again (apart from losing the previously used program and settings) - just as unplugging power.So it seems the microcontroller "hangs". But what may cause this?(Testing the board is a bit troublesome. Without the bike attached, it just shows error E-5 and does not respond to anything. The bike is big and heavy, so I can't bring it home and at my friend's place I have limited equipment. And even then it takes hours to days to reproduce)

author: fzabkar
author_rank: Super Contributor
timestamp: December 17, 2024, 06:26:08 pm
content: If you remove the EEPROM, does this generate an error code?I notice that the MCU has 2032 bytes of RAM. Is that where the settings are stored, or are they stored in EEPROM?https://www.application-datasheet.com/pdf/cypress-semiconductor/mb95f378epmc1-g-sne2.pdf

author: mahi
author_rank: Regular Contributor
timestamp: December 17, 2024, 06:38:30 pm
content: Without the EEPROM the exercise bike does not work at all. The display remains dark.I can read and write the EEPROM in a standalone programmer, but obviously I do not know what exactly its content represent.
DL24M cleaned from mask circuit board - Page 1
Forum section: electronics / repair

author: selevo
author_rank: Contributor
timestamp: July 08, 2024, 08:40:17 pm
content: To remove the mask, I used liquid pipe cleaner. The base is NOH (caustic soda).immersed for 24 hourshttps://cloud.mail.ru/public/2SQh/4uQRhLzwW50mb
DLink M30 Wifi router Ethernet switch chip repair - Page 1
Forum section: electronics / repair

author: TimSmall
author_rank: Newbie
timestamp: July 19, 2025, 04:48:21 pm
content: I have a wifi router with a faulty switch. I bought it as working, and was given a full refund when I reported it faulty. Looks like the seller had bought a pallet load of Amazon returns, and sold them off with minimal testing.It's a DLink M30 Wifi6 router which I plan to put Openwrt onto.There are 5 Ethernet ports on the router. The WAN port (yellow in attached photos) goes directly to the SoC, and the 4 'LAN' ports go to a MT7531AE switch IC (which has its own connection to the SoC).There are 2x dual magnetics packages for the switch chip, and a separate magnetics package for the WAN port. No link gets negotiated when plugging another Ethernet device into any of the LAN ports (WAN port is fine).I've soldered in a header for the console UART, and there are a load of messages like:[ 60.600818] mt753x-nl: failed to find switch devno chip unsupport or chip id is invalid!mt753x deal request errorRead failmt753x deal request errorRead failno chip unsupport or chip id is invalid!I don't have a schematic, but I'd guess it's very similar to the Banana Pi implementation on page 10 of:Banana Pi BPI-R64-SCH-V1_1-iPA-20191028.pdf... which can be found readily online.I assume the switch chip needs replacing (LCSC has them for USD 2.50), but what should I check first? Power supply rails (voltage and ripple), but not sure what else? I only have fairly basic test kit - a DMM, a 20 MHz USB scope and a 20 MHz USB logic analyser.The MT7531AE is an 0.4mm pitch LQFP128, which I think I can just about handle replacing using some bismuth solder and a hot air gun (although there are a few 0402 passives pretty close).
DMM contact wipers - Page 1
Forum section: electronics / repair

author: Traceless
author_rank: Frequent Contributor
timestamp: August 06, 2022, 03:08:55 pm
content: Hey everyone,I'm currently looking for some contact wipers to repair a DMM "Finest 201" (see picture below, the contacts are about 12x4mm, measured flat without the bend). Looking on Ali and ebay I didn't find anything useful searching for "contact wipers" and "wiper contacts". Maybe I'm using the wrong search term. Does anyone know a source for replacements?

author: floobydust
author_rank: Super Contributor
timestamp: August 06, 2022, 07:47:07 pm
content: Because it's a part of a part, and worth pennies, unfortunately a (the?) manufacturer has not been found.For the multimeter rotary switches, the chinese copied 1989Actron US patentin ANENG, Mastech, Uni-T etc.It's in the same league as battery contacts, springs, other stamped metal pieces. The keyword "shrapnel" is used with them for some odd reason. Kind of thing these guys likely makeDongguan Bosi Hardware Electronic Co., Ltd.https://www.eevblog.com/forum/projects/where-to-get-multimeter-knob-contacts/https://www.eevblog.com/forum/repair/agilent-u1272a-missing-contact-rotary-switch/If you have oxide and poor contacts, I find a contact cleaner which has Polyphenyl Ether (PPE) works good. Environmental regulations caused the product names to be changed over the years.In North America, CAIGDeoxIT F5works for me.In Germany it was calledCramolina long time ago Red or R-100. I think it's Cramolin SCHUTZPROTECTIONused after cleaning the switch. But not with abrasive or the gold plating is gone, if there is any.These sprays are available at audiophile and music supply stores.

author: Traceless
author_rank: Frequent Contributor
timestamp: August 06, 2022, 08:25:36 pm
content: Hey floobydust,thank you, the "shrapnel" keyword already helped to at least findsome similar itemson aliexpress. Surprisingly they are relatively expensive 5 contacts for 7€ incl. shipping. It seems to be cheaper to buy one oftheseand take the contacts out, assuming those have similar contacts XD.Unfortunately corrosion is not the problem but one of the contacts is missing, the meter was given to me as not properly working after a fuse was replaced. So I guess the contact fell out unnoticed during fuse replacement. The manufactuer seems to be a Korean Company called "Fine Instruments Corp.", not sure if they are still around. I think the meter was made in the 1990s. It is not a Fluke or Brymen but the build quality looks decent.

author: floobydust
author_rank: Super Contributor
timestamp: August 06, 2022, 08:39:27 pm
content: Ahhh yes search term "Multimeter Shrapnel" shows them too on eBay, but the same lone shenzen expensive supplier over $1 each. Let us know if you find anything better for price.Search term is "Battery Shrapnel" for replacement battery contacts, for Fluke multimeters etc.
DMM failing to meter DC voltage unless after minute waiting - Page 1
Forum section: electronics / repair

author: abdulbadii
author_rank: Frequent Contributor
timestamp: November 07, 2022, 01:27:05 am
content: Anyone experienced how to solve a DMM (of medium quality not top/best one) failing to meter DC voltage unless after probing several times later or perhaps just waiting a minute or so later, after which it will work normally for the needed measurement

author: BILLPOD
author_rank: Frequent Contributor
timestamp: November 07, 2022, 07:36:14 pm
content: abdulbadii, What is the make and model of your medium quality DMM?

author: alm
author_rank: Super Contributor
timestamp: November 07, 2022, 08:17:37 pm
content: Sounds like a bad contact or open (fusible?) resistor in series with the input to me. What is the input that you measure when you measure resistance with the meter set to DCV between the V/Ohm terminaland COM terminal with another DMM, and what is the input impedance specified in the manual for that DCV range? And is this value stable or does it slowly change like the reading on the defective DMM?

author: Grandchuck
author_rank: Super Contributor
timestamp: November 07, 2022, 09:25:39 pm
content: Are you sure it is the meter? Do you have another one?
DMM Metex M-3850 damage by high voltage - Page 1
Forum section: electronics / repair

author: Michaelt
author_rank: Newbie
timestamp: March 26, 2022, 08:08:59 pm
content: I wanted to step up voltage using transformer I took from AC adapter, so I connected secondary windings to 12VAC adapter, which would in theory produce 300-400V on primary. Then I wanted to measure voltage on primary using my multimeter(which is rated for 750VAC), but the problem is that I probably accidentally disconected transformer from power supply which resulted in high voltage being produces on primary? I'm not really sure but then I just heard some spark, like that from "high voltage generators", multimeter instantly turned off.After turning it on I found out that all functions except "TEMP (Room)" are dead. More specifically they show same UI as temperature function so the units are always degrees celsius.But millivolts work a bit, they can distinguish polarities and also show some values according to increasing decreasing voltage, but as I said it's in "TEMP (Room)" mode so the values aren't accurate. Resistor meassurements shows 0L when disconnected which is correct, but once I meassure something and then disconnect it the value on display doesn't change to 0L, it just starts rising slowly. Milliamps function has "LOGIC" UI instead of "TEMP", it shows "rdy" value which corresponds to LOGIC, but on bottom of screen there is another "display" that shows values as if it was on analog ammeter, suprisingly it shows values absolutely correctly in 0-40mA range, when I go over the range nothing happens, normally it would switch to 40-400mA range or something like that.Also I can't switch between AC and DC measuring mode but it doesn't surprise me much because I'm stuck in Temperature function.I appreciate any tips although I think it is permamently damaged. Tried looking into service manual but found nothing about my problem.After reading my text again, seeing how badly damaged it is, I guess that I'll use my multimeter as room thermometer

author: Emo
author_rank: Regular Contributor
timestamp: March 26, 2022, 08:26:17 pm
content: Hi,Had this myself long time agoIf you are lucky the chip under the display, probably a maxim ICL7106 or ICL7107, is in a socket and easy replacable.Eric

author: Kleinstein
author_rank: Super Contributor
timestamp: March 26, 2022, 09:17:35 pm
content: AS the meter seems to be 4000 count, the main chips is not a 2000 count chip like ICL7106.It sounds a bit like the main DMM chip does not get the info which range is selected. If lucky this is some burnt resistor of switch contact that can be fixed. If no so lucky the main DMM chip is damaged and chances are than small to fix it.A first point would be opening the meter and look if there is visible damage (chared PCB, burn-marks on a resistor, maybe a bad MOV or PTC ).I have not much hope for a successful repair, but one could still have a look.
DMM resistance test, shows abnormally high values - Page 1
Forum section: electronics / repair

author: sdancer75
author_rank: Frequent Contributor
timestamp: July 02, 2020, 05:30:42 pm
content: Hi,This is my spare "mobile" DMM that I am using out of home for emergency situations. I always store it in my car.Lately, I noticed that sometimes -but not every time- it shows high resistance but after a while (~5 to 10 minutes), it comes back to normal.As far as I know after a quick test, AC, DC, Diode, and capacity work fine. Probes also are fine.What kind of problem is this? Maybe a rusty connection or high temps inside my car?

author: bob91343
author_rank: Super Contributor
timestamp: July 02, 2020, 05:48:04 pm
content: This is simply a poor connection. It can be in the switch or the test jacks. Even a slight corrosion of the test probes can cause it.That's why a four wire Ohms setup is far superior; it doesn't much care about such things.

author: sdancer75
author_rank: Frequent Contributor
timestamp: July 02, 2020, 06:04:59 pm
content: Quote from: bob91343 on July 02, 2020, 05:48:04 pmThat's what I thought. I will open it to check it out.Thanx
DMM sees GHOST Voltages - Page 1
Forum section: electronics / repair

author: Antonius
author_rank: Newbie
timestamp: September 03, 2020, 09:05:03 am
content: Hello I have an old DMM from Siemens B1002, the open circuit probe AC Voltage values after switching ON randomly beginhighin hundreds 700ish, 1074, 666, 240... then it very slowly counts down, and a bit up again(very weird)hanging around at ~14 Volts, 48, 21, etc., never reaching 000. Why is the DMM doing this? I have changed the Battery to a fully charged 9V Battery.

author: goaty
author_rank: Regular Contributor
timestamp: September 03, 2020, 09:28:08 am
content: - Does it behave different in DC voltage ?- Short the leads, does it change ?- Measure with another meter the input impedance in DC should be 10MOhm.- Maby the rectifier circuit around the TL066 is damaged. Check the 1N4148 and caps.- Also clean any dirt on high impedance circuitry. There is 22MOhm feedback resistor around TL066.
Dmm Yokogawa 732-02  ohm measure issue - Page 1
Forum section: electronics / repair

author: Netmark
author_rank: Newbie
timestamp: March 25, 2024, 07:23:27 am
content: Hi guys,I have 2 dmm yokogawa 732-02, one of them being battery corrosion. After cleaning, the corrosion dmm measure in ohm range is slow. When you take lead test into resistor the number go higher compare to normal one before come back to precision value. It still precision, but slow measurement compare to normal one.I have tried to cleaning main chip and resistor that it use in ohm range and expose it to sun light. After that its measurement become fast as normal one. But after a few day, it slow again @@Please help me find out problems!Or any suggestion.I also want to know more about dmm schematic and its working principles, could you suggest any good book.Thanks and sorry about my english!

author: MathWizard
author_rank: Super Contributor
timestamp: March 25, 2024, 09:39:46 am
content: With auto-ranging on DMM's, sometimes when oil/dirt from my hands, gets on the probes, the DMM will take longer.Can you really measure a time difference ? I'd use the same probes, even the same battery, turn on or off auto-ranging, and compare them.As for books/manuals, look up DMM service manuals, most of the top DMM's from before the 1990/2000's, have nice detailed manuals, with theory of operation, and schematics.There's lot of old analog volt/ohm/amp meters too, like Heathkit, all their manuals are in a few archives.Heathkit Schematic and Manual Archivehttps://www.vintage-radio.info/heathkit/Besides the chips getting smaller, I don't think much has changed, and most DMM's work about the same.Fluke87 DMMhttps://xdevs.com/doc/Fluke/83_85_87smeng0500.pdf

author: Netmark
author_rank: Newbie
timestamp: March 25, 2024, 10:56:52 am
content: Thanks for your rely,This is the test of normal onehttps://youtu.be/BQF7JXbeKCo?feature=sharedThis is the defective onehttps://youtu.be/2mgGlNrlJdw?feature=sharedIt's easy to feel the different of measure speedIf i try to wait a little, the number will go down, example in test 1 ohm resistor that it will count down to 1.1 but very slow.I use the same probe. Battery be tested in good condition for allMay be, i need to desolder chip and relevent resistor, then cleaning and soldering again. May be it will resolve the problems, because it is new dmm but storage with battery inside, so the issue come from battery corrosion. Just guess @@
DMM6500 Keithley Error Code 1153  - Page 1
Forum section: electronics / repair

author: faster91
author_rank: Newbie
timestamp: April 25, 2024, 08:39:21 am
content: I have a Keithley DMM6500 6.5 Digit Multimeter. Few days ago I encountered in the error 1153.The Error Code 1153 indicates a problem with the internal power supply. I tried to update the firmware and checked the voltage at the source, but it was ok.Does anyone have any suggestion?Thanks.

author: m k
author_rank: Super Contributor
timestamp: May 01, 2024, 04:49:28 pm
content: If machine can sense more it must also have more sensors.Those sensors can also go faulty and then report incorrect problems.Manuals I found were not helpful.Is the code a single number or something packed?

author: hugos31
author_rank: Regular Contributor
timestamp: March 27, 2025, 07:17:51 pm
content: I have the same problem

author: voltsandjolts
author_rank: Unknown
timestamp: March 27, 2025, 07:25:18 pm
content: Line voltage is set correctly on the rear panel, right?!What does the event log say?

author: hugos31
author_rank: Regular Contributor
timestamp: May 20, 2025, 02:55:13 pm
content: Line voltage: 205 VAC. The correct voltage would be 220V AC. I tried it somewhere else and the problem was solved.
do freezing NiCad rejuvenate them or what would you recommend - Page 1
Forum section: electronics / repair

author: pcmad
author_rank: Regular Contributor
timestamp: April 14, 2021, 08:43:12 pm
content: do freezing NiCad rejuvenate them or what would you recommend

author: wraper
author_rank: Unknown
timestamp: April 14, 2021, 08:48:30 pm
content: Quote from: pcmad on April 14, 2021, 08:43:12 pmWhy some random action should restore them?QuoteDisposing them.

author: joseph nicholas
author_rank: Frequent Contributor
timestamp: April 14, 2021, 09:33:44 pm
content: Everything wears out, get use to it.

author: RoGeorge
author_rank: Super Contributor
timestamp: April 14, 2021, 10:19:27 pm
content: Ni-Cd rechargeable batteries have memory. Try a few cycles of discharging them to zero volts then charging, in order to remove the unwanted memorized discharge level.Another common mode to fail is they grow dendrites internally and short circuit themselves. This fail mode can be removed by braking the dendrites with a very high current pass through the battery. It works but soon the dendrites will grow again, so this kind of recovery is not very useful.NiCd technology was replaced long time ago by NiMH or Li based rechargeable batteries, so long ago that most of the times it doesn't worth trying to recover NiCd.

author: Monkeh
author_rank: Super Contributor
timestamp: April 15, 2021, 12:41:19 am
content: Quote from: RoGeorge on April 14, 2021, 10:19:27 pmNot on planet earth they don't.

author: RoGeorge
author_rank: Super Contributor
timestamp: April 15, 2021, 01:03:11 am
content: https://www.electronics-notes.com/articles/electronic_components/battery-technology/nicad-nicd-nickel-cadmium-memory-effect.php

author: Monkeh
author_rank: Super Contributor
timestamp: April 15, 2021, 01:06:12 am
content: Quote from: RoGeorge on April 15, 2021, 01:03:11 amWhich references my point.You need consistent charge/discharge cycles to see the memory effect, far more consistent than you'll see in consumer use. It was discovered on satellites.

author: MikeK
author_rank: Super Contributor
timestamp: April 15, 2021, 01:31:33 am
content: The "memory" effect originated with satellite use, having very specific and regular charging circumstances. See the wikipedia page on it. Most people won't experience it.Anywho...Why are these NiCads being rejuvenated? Are they old and at the end of their life? Or something else?

author: Circlotron
author_rank: Super Contributor
timestamp: April 15, 2021, 03:32:04 am
content: https://batteryuniversity.com/learn/article/how_to_restore_nickel_based_batteries

author: james_s
author_rank: Super Contributor
timestamp: April 15, 2021, 05:45:29 am
content: I've managed to squeezer a little more usable life out of tired NiCd batteries but generally speaking it isn't really worth it. At some point they're just worn out and the only thing you can do is replace them.
do ram chips break much? - Page 1
Forum section: electronics / repair

author: coppercone2
author_rank: Super Contributor
timestamp: September 12, 2024, 04:13:33 am
content: I have to replace a TC5514P to trouble shoot my 4191A.Is it likely that ram chips like this break? Do they have a bad reputation? I know modern computer ram is pretty shady.I noticed one of the batteries was dead (0.4V, the other was 1.1V).I read about those old logic chips possibly getting burn out when they get stuck on a voltage near some thresh hold. Is it common for them to go when batteries go? In this case it might have been running at 1/2 standby voltage for a long time. Some gate can get stuck in transition region on the chip and burn out?Kind of like the problem when you have too much fan out, it says that can break some chips physically if signal is low. I thought maybe if power is like that it might not like it and stress something?

author: fzabkar
author_rank: Super Contributor
timestamp: September 12, 2024, 04:17:45 am
content: I replaced numerous SRAMs, DRAMs, and PROMs during the 1980s.

author: coppercone2
author_rank: Super Contributor
timestamp: September 12, 2024, 04:21:10 am
content: I don't like my odds because its 2020sthis unit was working but it was a little futzy sometimes, you needed to reset it sometimes. Maybe it was a sign of that ram going bad.Lol, I have the god damn calibration standards for this thing too. Failure is not a option. It was supposed to be my inroad to impedance understanding.

author: fzabkar
author_rank: Super Contributor
timestamp: September 12, 2024, 04:27:12 am
content: Quote from: coppercone2 on September 12, 2024, 04:21:10 amI'm looking at a datasheet dated 1985 ...

author: coppercone2
author_rank: Super Contributor
timestamp: September 12, 2024, 04:29:48 am
content: The first thing they need to build on mars is a semiconductor factory so they can replace their life support assy when it gives a e21I like this machine though, it is fairly easy to work on like a pickup truck, I don't have elevated vital signs when I am thinking about doing a card level repair on it. Putting that PCB on the hood that lifts up is a brilliant idea. I wonder how many heart attacks that prevented.

author: coppercone2
author_rank: Super Contributor
timestamp: September 24, 2024, 02:27:58 am
content: ok its alive, wants CAL and gives the usual BS on startup, so it is as good as it was.Maybe I can fix the god damn welder now, I made sure to leave the 4191A on my lab chair, so I don't work on anything else until I fix it. quite a obstacleReplaced while board was in chassis using solder pump/wick, hot tweezers and careful soldering, because there was just way too little room to work on it lolall those ceramic chips... makes me not wanna move the board, last thing I need is for it to slip and crack a ceramic component. I don't have 2x2 foot PCB holder (yet), makes me feel like a bumI should get a nice heavy high quality artist ezel and put big boards on it ! Now that would be a good project!
Do you know what these to missing components are on this 2080 ti turbo?  - Page 1
Forum section: electronics / repair

author: Eg3300401
author_rank: Contributor
timestamp: January 24, 2023, 03:22:05 am
content: Are they both caps or is the Little on a resistor and the big one a cap?

author: newtekuser
author_rank: Frequent Contributor
timestamp: January 26, 2023, 04:21:19 am
content: You're actually missing two caps, a big one and a small one. Here's a pic of my 2080ti

author: Eg3300401
author_rank: Contributor
timestamp: January 26, 2023, 04:30:39 am
content: Thank you!!!
Do you know what this IC chip is? - Page 1
Forum section: electronics / repair

author: Johnny10
author_rank: Frequent Contributor
timestamp: June 22, 2019, 04:37:42 pm
content: I am having trouble finding information on this chip.Maybe I need more coffee can't seem to find it.Ti 30165 Should be 30615OOPS ! I have that habit.It is from a Fluke 8846a mainboard.

author: bob91343
author_rank: Super Contributor
timestamp: June 22, 2019, 04:48:05 pm
content: Take another look. Your post gave a number which isn't the same as in the picture. Was that a typo?

author: rfeecs
author_rank: Frequent Contributor
timestamp: June 22, 2019, 05:28:40 pm
content: TPS3306-15D?http://www.ti.com/lit/ds/symlink/tps3306.pdf

author: Kjelt
author_rank: Super Contributor
timestamp: June 22, 2019, 08:13:22 pm
content: Quote from: rfeecs on June 22, 2019, 05:28:40 pmYes that is the one on the datasheet addendum page 1 it states the same device marking code forTPS3306-15DR.

author: fzabkar
author_rank: Super Contributor
timestamp: June 23, 2019, 01:31:10 am
content: Just FYI ...http://www.ti.com/packaging/docs/partlookup.tsp
Do you recognize this mysterious reed relay? IEI MT03A - Page 1
Forum section: electronics / repair

author: cincin
author_rank: Regular Contributor
timestamp: November 03, 2024, 06:22:33 pm
content: I'm fixing an old Anritsu MS420K VNA where the input reed relays (IEI MT03A) of both channels have blown coils. I'm looking for suitable replacements.I can't find anything at all about these MT03A online. No datasheet, no mentions, no specs. Google Lens is no help at all.The circuit involves many of them, all but the front ones are working.It's a SPST-NO with 4 pins at the corners. Likely 12V given its neighbors. There's 540 Ohm across the coil pins of working ones. 20mm between the far legs, 4.5mm between the near legs.Do you know the specs of these?How can I otherwise figure out a good replacement?Cheers!

author: cincin
author_rank: Regular Contributor
timestamp: November 03, 2024, 06:57:30 pm
content: Things are starting to look grim, I can't find any reed relay in that form factor...It seems like a shame to put the first signal path relay on non-shielded long pins to accommodate a different shape.What do?Cheers!

author: fzabkar
author_rank: Super Contributor
timestamp: November 03, 2024, 07:01:47 pm
content: A clue?IKUNO ELEC-TROL, INC or just plain ELEC-TROL

author: cincin
author_rank: Regular Contributor
timestamp: November 03, 2024, 07:12:35 pm
content: Thanks! So it's an Ikuno Elec-Trol!I'm so hooped on this haha. Why did they use the most obscure relays.I'll have to find a similar VNA for parts at this point...

author: fzabkar
author_rank: Super Contributor
timestamp: November 03, 2024, 07:17:40 pm
content: I recall that I had some Electrol reed relays in a different pinout. Be aware that some incorporate a diode across the relay coil.

author: fzabkar
author_rank: Super Contributor
timestamp: November 03, 2024, 08:07:37 pm
content: FWIW, Hamlin has an extensive cross-reference to Elec-trol reed relays.https://web.archive.org/web/20000925185216if_/http://www.digi-key.com:80/EC/V3/465.pdfIt might be worth checking if they have something with the same pinout.Perhaps you could adapt a SIP relay? The coil could be rerouted without affecting signal integrity.
Do you think I have over done it on these replacement resistors? - Page 1
Forum section: electronics / repair

author: mendip_discovery
author_rank: Super Contributor
timestamp: March 26, 2021, 07:29:58 pm
content: These are the 2 Ω and 0.5 Ω continuity resistors for a Multifunction Tester calibration test box (Transmille 2080) but I thought I would replace it with lower tolerance from 5% to 1% and up it on the Wattage considering my workmates managed to blow the old ones. It is easy to do, they share a common with the 1 MΩ, 10 MΩ and 99 MΩ insulation test resistors.

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 26, 2021, 10:25:48 pm
content: Nah, they're still on the small side...As long as you have enough clearance to shut the box and not risk having a resistor melt its way out it should do the job.Now that the resistor is no longer the weak point you may want to reconsider fusing just in case.

author: mendip_discovery
author_rank: Super Contributor
timestamp: March 27, 2021, 08:58:18 am
content: If you look at the circuit, it is tagged onto the side of the in for the 2and onto the pad for the COM so not much room for fuses.If you look at the surface mounted resistors they are for 1, 10 and 99M and take the 1kV loads.

author: perieanuo
author_rank: Frequent Contributor
timestamp: March 27, 2021, 04:27:53 pm
content: Quote from: mendip_discovery on March 26, 2021, 07:29:58 pmupgrading the power in your case serve no logic, maybe you will move the problem in a place not so easy to repair next time your workmate repeats the bad movethe tolerance, that's same thing, i'd guess you will recalibrate after replacing the resistors anyway and without putting on paper the whole schematics we can't estimate if replacing part of divider with higher precision will improve greatly the precisionyou can easily stick to the originals, maybe the power was calculated for those resistors to fail and not the ucontroller after them

author: factory
author_rank: Super Contributor
timestamp: March 28, 2021, 08:37:15 pm
content: I agree it's a bad idea to replace a sacrificial element such as the low power resistor with a bigger wire-wound one, instead of failing in a controlled manner with an open resistor it may cause damage elsewhere, worst case you could end up with a very burnt PCB, which would be more costly to replace.The comment about adding fuses, remember that fuses have resistance and it may not be possible to adjust the circuit to compensate for this.David
Document dump from 3Y Power Technology company FTP server - Page 1
Forum section: electronics / repair

author: hanakp
author_rank: Regular Contributor
timestamp: January 09, 2023, 10:31:24 pm
content: I'm a bit reluctant to post this, but I don't think it violates any forum rules, so I'll bite. Back in 2016, I made a dump of a FTP server that belonged to 3Y Power Technology in China. The FTP was completely public and unprotected back then, so I didn't break any laws by doing so. Most of the contents even used to be indexed in Google, that's how I found it in the first place. Well, it's been 6 years now and the FTP is long defunct, so I doubt anyone will care. But in case somebody does:download and save it while you can!The company has been manufacturing SMPS for server markets, I've seen HP, FSP or Juniper, among others. I didn't see any schematics, but for many SMPS, there are various technical reports, statistics, assembly instructions and the like. The repair crowd here will be probably most interested in RMA failure analyses which list the most problematic components. Note that lots of the files are just slightly different versions of the same document, lots of them are in Chinese and lots of them are completely garbled (due to bad character encoding, I think). Still, here it is in RAR archive, it has 2800 MB:https://mega.nz/file/93Y3jIYJ#5Pkyl3u39G__G1n5jOfIX7wRkilpjCZu2jurQaEdoBwAnd here is list of some 3Y products I've seen in the files, but I'm sure there are more:YH8451YM-2451CERYM-5501ARR-3514-00YM-3571AARFSP288-3F03YM-6151AARYM-1151BARYH1361-OAARRP-3863-00YM-2651BC02RFSP118-3F01YM-4151AARRRG-4514-00YM-2181BARFSP225-4F01YH6501-1KARYM-3591AARYH5721-1BARFSP368-4F04YM-6221AARYM-3301BARYM-2531BARRM-5803-00EVP-3606-00YM-3201AARYM-5301GERYM-7381CB02RYM-7421DARYM-5561ABRFSP030-1P04YH7761-2AR02RYH8451-1BE04RYM-2301CARFSP350-80EVMRYM-2102BBRYH5721-1AB05RYH8651-1BA08RYM-2361EAR

author: Chris56000
author_rank: Frequent Contributor
timestamp: January 09, 2023, 10:44:26 pm
content: I'm downloading a copy for my personal use now!Thank you Sir!Chris Williams

author: ingalopez
author_rank: Contributor
timestamp: January 09, 2023, 11:28:31 pm
content: Thank you!you hacker you...!
DOD R-431 31 band E.Q. had much 60hz hum, now fixed - Page 1
Forum section: electronics / repair

author: CaptDon
author_rank: Super Contributor
timestamp: December 05, 2022, 01:59:57 am
content: I made some improvements on the low frequency end of my night club sound system and traced a significant amount of hum coming from the graphic E.Q. I was surprised to find the hum at pure 60Hz. Moving the 120Hz control made no difference. First off, the unit is not chassis grounded and also doesn't have any bypass capacitors to the chassis. The power supply wires to the various circuit boards looked very feeble so I beefed up the grounds with much heavier wire. NO CHANGE in hum level. I then found when I placed my hand near the tiny power transformer (it is magnetically unshielded) the hum reduced so I installed some copper shielding around the transformer and a copper riser between the transformer and the audio boards. BARELY ANY CHANGE. Again I noticed placing my hand in that area reduced the hum. Aha.... The 120v.a.c. hot wire and fuse holder are barely 1/4 inch away from audio hi impedance circuitry. I installed a grounded copper shield between the 120 volt a.c. wiring and the audio circuits. Hum reduced by at least 20Db. There is still a tiny bit of hum coming from within the E.Q. unit, but it is small enough that I can accept it. Feeble and poor design throughout, and yet DOD audio gear is generally ranked well in quality for pro gear. Just wanted to share my story of marginal gear which took some time to figure out.

author: AkibUddin
author_rank: Contributor
timestamp: December 05, 2022, 03:36:06 am
content: Quote from: CaptDon on December 05, 2022, 01:59:57 amCan you show with us about your work

author: CaptDon
author_rank: Super Contributor
timestamp: December 05, 2022, 01:18:44 pm
content: Sadly, the unit is reassembled and back in use in the equipment rack. I should have taken some photos. I had always noted a bit of hum in the low frequency folded horn bass bin but recently had the chance to connect the low frequency amplifier to a cabinet loaded with 18" speakers and the hum became very pronounced in a quiet room. This sent me searching for the cause. I though it would show up as ground loops or poor interconnect cabling but was surprised to find what I would call a design flaw in a piece of audio equipment. This particular system is used for bands in small night clubs, American Legion, Veterans of foreign wars, and the 'animal clubs' Elks, Moose, Eagles and the like. Cheers mates!!
Dodgy hall effect input on microwave controls. - Page 1
Forum section: electronics / repair

author: Zog
author_rank: Regular Contributor
timestamp: June 09, 2021, 02:58:33 am
content: I haven't actually taken it apart yet so I am assuming it's a hall effect device.When the microwave was new it was very precise and could adjust it with ease.Now when I turn it it just jumps around all over the place. Sometimes advancing a minute like it's supposed to sometimes 10mins.I have noticed this happening on a few devices over the years. My car radio springs to mind. Similar problems.What on earth could cause this ? Maybe it's optical ?Optical would not be common in consumer electronics would it ?

author: Ian.M
author_rank: Super Contributor
timestamp: June 09, 2021, 05:34:53 am
content: Probably a worn out mechanical rotary encoder. Once enough of the contact fingers wear away, they typically become so intermittent that the debouncing can no longer cope and the direction of movement can no longer be reliably determined. If it is a mechanical encoder, its not too far gone, and you can get the encoder open without FUBARing it, then a thorough cleanout, retensioning the contact fingers and applying a good quality contact lubricant may get a bit more life out of it.

author: Zog
author_rank: Regular Contributor
timestamp: June 09, 2021, 08:59:29 am
content: Mechanical encoder. Didn't think of that. Would explain a lot.Why on earth put something like that in for gods sake.Typical of consumer electronics ?Cheers.

author: TheMG
author_rank: Frequent Contributor
timestamp: June 10, 2021, 01:29:02 pm
content: Yep, cause it's cheaper.A shot of contact cleaner usually does the trick with those mechanical encoders, provided it's not completely wore out.
Does any one know the resister values for a Triplett 660 Load check meter? - Page 1
Forum section: electronics / repair

author: Zenwizard
author_rank: Regular Contributor
timestamp: April 29, 2023, 12:58:22 am
content: I am thinking about integrating a Triplett 660 Load meter in to my current limited variac supply. But It seems some time between 1959 and now one of the resisters was cooked by to high a load on the low range. These use wire wound resisters, but I can not dig up a service manual or documentation on this unit. It is a very simple meter and should take about 2 seconds to repair if I can find the component values.Zen

author: Jim Beckford
author_rank: Newbie
timestamp: April 30, 2023, 06:58:01 pm
content: Does this help?
Does anybody know what this component is?  - Page 1
Forum section: electronics / repair

author: DMartens
author_rank: Contributor
timestamp: July 22, 2024, 04:34:34 pm
content: Found it in a grab-bag of components.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 22, 2024, 04:42:52 pm
content: if i recall ferrite bead but 5 in line instead of single onewith an ohm-meter you should not read anything from the nearby pins, but only in frontsee attached picture of a 4xhttps://www.tradeindia.com/products/ferrite-bead-for-multi-line-suppression-c5060940.html
Does anyone have any Agilent/Keysight U3401A Digital Multimeter VFDs for sale?? - Page 1
Forum section: electronics / repair

author: Wahyueko
author_rank: Contributor
timestamp: December 14, 2022, 02:55:13 pm
content: I have an Agilent/Keysight U3401A Digital Multimeter but the VFD is broken as follows, does anyone sell this VFD, I have searched and haven't found it. Please help.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 14, 2022, 05:51:06 pm
content: check on Ebay ? or ask Keysight if they have some left ....And if they do, you have to be an business to order from themJust paid 200 $ CAD on ebay to get an 34410a vfd ?? ill know tonight if it was a good purchase loll no part available at KeysightAnd sadly you may have to buy another meter for the partor you try to fit some oled display project done by Qu1ck, not sur if its code compatible ...

author: MadTux
author_rank: Frequent Contributor
timestamp: December 14, 2022, 06:15:05 pm
content: Is that a Fluke 45 ripoff?Or even same design, just license build for cheap?

author: Wahyueko
author_rank: Contributor
timestamp: December 14, 2022, 06:38:56 pm
content: I checked on Ebay, but no one is selling it, sir

author: Wahyueko
author_rank: Contributor
timestamp: December 14, 2022, 06:41:49 pm
content: There seems to be a resemblance, sir, but I see a number of pins are different, and the series are also different, sir.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 14, 2022, 10:38:59 pm
content: I tought it was an mispelled 34401a i never saw an 3401 meterChecked and saw nothing of an cloned vfd ?? your last luck is still Keysight, you can check their parts availability ...Or try an OLED project who would involve communication sniffing and decoding etc .... like the 34401a OLED project here ...Even used, they dont sell for cheapgood luck
Does anyone have the schematics of the HP 5342A motherboard (A22)? - Page 1
Forum section: electronics / repair

author: gabor.dani
author_rank: Contributor
timestamp: December 14, 2020, 07:51:53 pm
content: I downloaded all the service manuals I can find, bought the original scans as well, but I cannot find the schematics of the A22 motherboard in any of them.If anyone here have it, please kindly attach it to this thread.
Does anyone know how to program this chip (m4a3-128/64 10vnc) ?  - Page 1
Forum section: electronics / repair

author: Unnit
author_rank: Newbie
timestamp: January 17, 2021, 10:17:56 pm
content: Hi, I have a sp300 printer and I am in the middle of a servo board repair. I found the problem comes from the "M4A3-128/64-10VNC" that is a CPLD chip (it is like an FPGA). The technique that I applied to find the short is, removing the parts from the VCC3 rail until the short is gone. The problem that I have is I don't know how to program the new chip and how to extract the "soft" from the old one (I have a motherboard that has a good chip on it)Down below I will put two links, one for the part from my local supplier (that contains also the datasheet of the part) and the other link is for the repair manual of my machine (unfortunately the link expires in 7 days but I will uploaded again and I will post it another 2 weeks).Please if someone knows about this type of servo board let me know so I can finish my job. Thank's!https://ro.mouser.com/ProductDetail/Lattice/M4A3-128-64-10VNC/?qs=%2Fha2pyFaduiFPkHO8R3uMUOfbd%2FjEm3JVItG7MBgcI7%2FX8ZoeGXikA%3D%3Dhttps://we.tl/t-25J6zXAD8g

author: Unnit
author_rank: Newbie
timestamp: January 17, 2021, 10:24:52 pm
content: Here is a servo board for referencehttps://www.digiprint-supplies.com/en/sp-540v-servo-board-7840605600-pborosp003

author: DC1MC
author_rank: Super Contributor
timestamp: January 17, 2021, 10:46:39 pm
content: The Lattice CPLD are programmable with Lattice Diamond Programmer, that can go from 20EUr, for an old parallel port device:https://www.ebay.de/i/183473944026or Chinese clone:https://www.ebay.de/itm/USB-Download-Cable-Jtag-SPI-Programmer-for-LATTICE-FPGA-CPLD-HW-USBN-2A/223492562126up to 250EUR for a "real" Lattice device, fortunately the software to program it is free.The problem is that CPLD has an internal flash where the bitstream is loaded AND a security bit that is 100% set and will prevent reading it back, even form an working board.On the other hand, compatible boards are allover on EBAY, China and local:https://www.ebay.de/i/313147834467https://www.ebay.com/itm/Generic-Roland-SP-300-SP-300V-SP-540-SP-540V-Servo-Board-7840605600-/263561789967so if you don't have a copy of the bitstream or a donor CPLD, your best option is to buy one of these boards.Also check the power supply voltages around, or if you have some motor controller board, in my experience Lattice devices are rock solid if not too complex and to have one fail by itself is pretty rare.Good luck,DC1MC
Does anyone know what Analog Devices IC this is? - Page 1
Forum section: electronics / repair

author: Generalquark
author_rank: Contributor
timestamp: April 25, 2021, 02:13:21 am
content: Hi,I was working on an Analog Discovery board and found a bad IC.I am not able to find what the component is. It may be some sort of regulator/boost IC.Pins on a good part readPin 1 4.95VPin 2 4.95VPin 3 4.95VPin 4 0VPin 5 0VPin 6 3.31VPin 7 3.31VPin 8 1.40VPin 9 2.93VPin 10 15.71VAny help identifying this part would be appreciated.Thanks

author: fzabkar
author_rank: Super Contributor
timestamp: April 25, 2021, 02:23:01 am
content: ADM1177-1ARMZ-R7, Analog Devices, Hot Swap Controller and Digital Power Monitor with Soft Start Pin, Automatic Retry Version, 10-Lead MSOP, marking M5Y:https://www.analog.com/media/en/technical-documentation/data-sheets/ADM1177.pdf

author: Generalquark
author_rank: Contributor
timestamp: April 25, 2021, 03:19:03 am
content: Well, that makes me feel stupid. That never seems to work for me so I don't even try anymore. Thanks for the simple advice and for linking to the part.

author: fzabkar
author_rank: Super Contributor
timestamp: April 26, 2021, 04:25:08 am
content: I used this resource:http://www.smdmark.com/en-US/search/code?id=m5y
Does anyone know what type of resistor this is and what is its value? - Page 1
Forum section: electronics / repair

author: limtk55
author_rank: Newbie
timestamp: October 17, 2020, 02:50:51 am
content: Hello guys,Attached is the picture of the resistorI am wondering if this is a metal oxide, or carbon film resistor or other types.Its color markings are blue black silver and gold.Can any experts out there advise me of its value?Thanks!

author: coromonadalix
author_rank: Super Contributor
timestamp: October 17, 2020, 03:29:39 am
content: 0.6 ohms ??6 0 divided by 0.01http://hirophysics.com/Labsheet/resis-codes/resis-codes.htmlNot sure its a flame proof resistor ?

author: limtk55
author_rank: Newbie
timestamp: October 17, 2020, 03:58:02 am
content: Quote from: coromonadalix on October 17, 2020, 03:29:39 amHi,I was looking at the codes as well and can't believe its 0.6 ohms (rated at 1W) too! Its connected to a power supply driver IC and I did some further probing and managed to find the schematic for it as well.Thanks a mil for the reply.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 17, 2020, 01:57:09 pm
content: i think there is a missing band between the blue and black ?

author: David Hess
author_rank: Super Contributor
timestamp: October 17, 2020, 06:05:33 pm
content: Blue Black Silver is 60 x 0.01 = 0.6 ohmsGold is 5% tolerance.And it looks like a flame proof metal oxide resistor.

author: KK6IL
author_rank: Regular Contributor
timestamp: October 22, 2020, 05:44:16 am
content: Looks like it's a 5 band resistor, blue, red, black, silver, gold.620 x 0.01 = 6.2 ohms, gold = 5%
Does anyone know where this probe comes from - Page 1
Forum section: electronics / repair

author: daisizhou
author_rank: Super Contributor
timestamp: December 02, 2024, 01:30:19 am
content: In the second-hand market, I purchased a probe that looks like an optocoupler sensor,I bought it because it was very cheap, so I bought it.I disassembled and found that there are 2 PCB components,It looks like a sensor for measuring liquids or gases, I can't be sure where it comes from.If you know where it comes from, please let me know. Thank you

author: Poroit
author_rank: Frequent Contributor
timestamp: December 02, 2024, 05:53:38 am
content: With all those O-Rings, it looks like some type of liquid level sensor.
Does anyone recognise this buck converter module please? - Page 1
Forum section: electronics / repair

author: peteb2
author_rank: Regular Contributor
timestamp: July 08, 2021, 12:03:03 am
content: It sports the Texas Synchronous Buck Controller type 40057... There are two versions that look identical, 12V input for either 3.8V or 12V in for 2.8V and the yellow coloured automotive style fuse F1 in the picture is rated 20A. 110mm x 36mm. They are mass produced in China going by the silk & no-brand electrolytics. Any info really appreciated.... thanks.

author: thm_w
author_rank: Super Contributor
timestamp: July 08, 2021, 12:36:41 am
content: Any specific info that cant be determined by:- thedatasheet- voltage rating of the capacitors- current rating of the FETs (assuming they aren't lasered)?I wouldn't trust the spec given on any website, and go based off the parts you see on the board.

author: peteb2
author_rank: Regular Contributor
timestamp: July 08, 2021, 01:00:41 am
content: I've just given the MOSFETS a good drink of acetone to remove the 'tropicalising'. My googling doesn't reveal anything for GV5H1D & i sure do not recognize the maker's logo. The "JSH" axial electros are 35V 125 degree at the input while the three at the output end they are 6.3V same maker. The board runs fairly screaming hot with same-sized alloy plate attached that's then clamped to a more substantial one.

author: peteb2
author_rank: Regular Contributor
timestamp: July 08, 2021, 01:20:07 am
content: .... Oops & here is a classic example of not going far enough!!! I finally, just now, did a truly full teardown on the module & wadda yuh know.... you uncover this label buried from view on that other side of the backing plate to the heatsink! DOLT!Thanks for the input so far ...

author: mon2
author_rank: Frequent Contributor
timestamp: July 08, 2021, 01:56:50 am
content: 1) MFRhttp://www.rong-electric.net/2) AOSMD mosfets p/n 6512 - datasheet is attached3) TI regulator p/n TPS40057 - datasheet is attached