hybridfree/eevblog-posts huggingface dataset:
plug in power meter flaw - Page 1
Forum section: electronics / repair

author: daniel444
author_rank: Regular Contributor
timestamp: May 07, 2024, 03:22:16 am
content: my plug in power meter just died , a few years earlier it had stopped working so i opened it up and found the built in battery leaking , so i cut the battery out and cleaned the electrolyte off the board.this caused it to work again for a few years , now it has stopped working again , the electrolyte had soaked into the board beyond my ability to clean it off , and its beyond my ability to repair.if your going to buy one of these power meters remove the built in battery immediately

author: BILLPOD
author_rank: Frequent Contributor
timestamp: May 07, 2024, 12:54:17 pm
content: Good Morning Daniel444, Maybe the 'battery' that leaked, and you removed, was not a battery, but a super capacitor. I'm just guessing here, but it's :horse:something to check out.
PLZ haelp: Problem with an oscilloscope model xds3062a - Page 1
Forum section: electronics / repair

author: JohnGalt
author_rank: Newbie
timestamp: December 23, 2020, 07:53:45 pm
content: So i have this perfect device and it just won't start. After i press the power button the run/stop button begins to blink red (sometimes some other buttons accompany) and it doesn't start, the screen is completely dark and no sounds going. Maybe there is a way to reinstall or upgrade the firmware from the usb or a computer in an off mode (some buttons combination or so?). Or should i be looking more in the depths of harware?
Plz help identify burnout resistor on thrustmaster t500 pcb - Page 1
Forum section: electronics / repair

author: freyz
author_rank: Newbie
timestamp: February 03, 2021, 11:18:47 pm
content: I am trying to save my Thrustmaster racing wheel after its motor stopped responding. I found a burned resistor on the mainboard that seemingly caused the issue. However, I don't understand its function and its marks all fade out.According to multimeter measurement, the resistor is between 24V positive and H-bridge motor controller. I don't see why such resistor is needed since both motor and MOSFET are rated for 24V. When I short the resistor the motor did rotate and work just fine. So my question is, what is this resistor and do I really need to replace it?This is the rough schematic about the resistor.

author: techneut
author_rank: Regular Contributor
timestamp: February 03, 2021, 11:32:44 pm
content: It is possible that the resistor is used for current sensing. It will then be around 1 Ohm or less.

author: freyz
author_rank: Newbie
timestamp: February 03, 2021, 11:54:35 pm
content: That makes a lot of sense. Is there still a way to figure out the exact resistance?

author: fzabkar
author_rank: Super Contributor
timestamp: February 03, 2021, 11:59:06 pm
content: I'm wondering if it is a fusible resistor.

author: fcb
author_rank: Super Contributor
timestamp: February 04, 2021, 12:12:14 am
content: See if there are some teardown pix on the interwebs of your exact model or ask someone to open one up and photograph the board. The resistor colour code will allow you to work out exact value.If it was a fusible resistor it wouldn't have burnt like that. Also, worth checking the FET's / motor /wiring - the resistor is likely to be a symptom of the fault not the cause.

author: freyz
author_rank: Newbie
timestamp: February 04, 2021, 01:00:15 am
content: The best photo I can find is this... But I don't know what it should read. I never seen a resistor beginning and ending with black. Do you have any idea?

author: picburner
author_rank: Frequent Contributor
timestamp: February 04, 2021, 08:30:46 am
content: FromQueen Mao Electronics: "Generally, If an additional fifth band is black, the resistor is wirewound resistor"and fromDigi-Keyresistor code calculator the resistor is 0.03ohm 1% that, given where it is placed, it might make sense.

author: fcb
author_rank: Super Contributor
timestamp: February 04, 2021, 11:56:05 am
content: 0.03 ohms seems pretty reasonable for that posistion. But to burn it out you're talking perhaps a couple of watts for awhile.P=I2R, so 2W would be 8.16A. Expect there to be another fault somewhere (blown FET?).
PM-100 with a low negitive rail.  - Page 1
Forum section: electronics / repair

author: Zenwizard
author_rank: Regular Contributor
timestamp: April 30, 2020, 11:51:37 pm
content: So I got a voltek PM100 from an auction site that we all know and love. And it has an issue of course. When I start it up it only goes to current over range. This appears to be a power supply issue as it started working after about 20 minutes of on time. I have confirmed that the tl072’s are not getting enough power on the negative rail it is down around a volt when compared to the positive rail. Does anyone know how the isolated power supply works in this thing? Or do I need to start hunting with a curve tracer. It has worked on my bench but stopped working but I suspect it is leaky electrolytics.
PM 3000A Issue - Page 1
Forum section: electronics / repair

author: Zenwizard
author_rank: Regular Contributor
timestamp: August 21, 2021, 08:28:49 pm
content: I have a voltech PM3000A on the bench that seems to have been locked in 1 channel mode. I keep getting invalid function when I try to switch to channel 2 or 3. I have looked for a service manual bur so far have been unsuccessful. I have read the user manual but it seems like the config is locked for editing. Does any one know how to factory default the unit to get it back to a known state. I am drifting between a possible corrupted firmware to a possible software lock out. Any time I try to change the wiring scheme or enable channel 2 or 3 I get invalid function. Channel 1 however measures and works as expected.Zen
pm 3055 scope , power supply problem - Page 1
Forum section: electronics / repair

author: frankhertog
author_rank: Newbie
timestamp: November 16, 2019, 10:03:12 pm
content: Hi guys,I encountered a nasty problem with my PM 3055 scope, one time not starting and the next moment perfectly working. the problem: after starting the scope the power supply goes in the protection mode (no display and a high pitched sound). the triac in the 48v circuit is conducting so the 48v + and - are clamped and the output of al the voltages are near to zero. I made a dummy load as described in the service manual. after connecting this to the power supply the problem was sometimes gone and sometimes not. Some of the condensors showed expansion and I suspected short circuit in a condensor that repaired after restarting and applying tension to the power supply. next I exchanged the condensors of the power supply and the problem was gone for about 2 years. Again mounted the dummy load the problem stayed. Clamping the gate of V6112 to -48V to prevent the triac going into conduction so I could test the system without the protection coming in action was not successful. after close inspection of the board I saw that the triac was touching the casing of the nearby transformer 6001. after creating a gap between the triac and the transformer the problem was gone and the system functioned correctly.

author: george.b
author_rank: Frequent Contributor
timestamp: November 19, 2019, 12:08:16 pm
content: Interesting. My PM3055 does that sometimes. I shall take a look.

author: Shock
author_rank: Super Contributor
timestamp: November 19, 2019, 04:26:35 pm
content: http://ftb.ko4bb.com/getsimple/index.php?id=manuals&dir=PhilipsPhilips PM3055 60 MHz Dual Time Base Oscilloscope Service ManualPage 9-5 on the power board V6101 V6102? look really close to T6001 is that what you are talking about? V6112 looks like quite a gap on this example.
PM2525  - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: April 07, 2022, 01:43:03 pm
content: Good morning all! I am looking for the input wiring diagram (banana plugs) on a PHILIPS PM2525 multimeter (gray); on mine; the card connecting the inputs is missing, and the banana plugs are broken.....I am attaching a photo of the missing card on my multimeter that I recovered on this site on an old post.... Thank you for your help !

author: wn1fju
author_rank: Frequent Contributor
timestamp: April 08, 2022, 12:39:45 pm
content: I pulled the card out of mine and took photos of front and back. You should be able to reverse engineer the wiring diagram from that. The capacitors measure 100 nF, but I have no idea about the inductor.By the way, I have found the PM2525 to be just about the most ridiculous DMM I've come across. From the idiotic motorized switch, to the nearly impossible calibration procedure, to the mediocre specs, I am not at all happy with it. Just my opinion....

author: lionelkjh
author_rank: Frequent Contributor
timestamp: April 08, 2022, 01:24:37 pm
content: Thanks a lot!!!
PM3219 analog storage scope: screen constantly lit even when memory is off - Page 1
Forum section: electronics / repair

author: ihackthestate
author_rank: Newbie
timestamp: April 09, 2022, 04:50:45 am
content: My PM3219 has a constantly lit up screen except during autostorage mode, which is odd. From youtube videos and documentation I've gathered that this is not supposed to be this way. I've followed the calibration steps in the manual but am unable to reduce this constant screen brightness, regardless of this probably being related to the storage mode, it seems to be able to still store though the image is faint. In normal operation I can still see the trace over the well lit background but its making it hard to operate how do I go about debugging and fixing this?

author: ihackthestate
author_rank: Newbie
timestamp: April 09, 2022, 11:23:50 am
content: I think it might be the issue philips described where the storage mode is always active as seen in this service document.https://xdevs.com/doc/PHILIPS/pm3219%20.pdfwill report if this procedure helped (and even was applicable by testing if g9 is at 110v regardless of mode).
PM9608B prescaler info wanted - Page 1
Forum section: electronics / repair

author: Rene Jansen
author_rank: Contributor
timestamp: July 08, 2022, 10:45:05 am
content: Hello,Can someone help me with some info about the PM9608 prescaler from Fluke/Philips?Schematic, parts list, adjustment procedure..... Everything is welcome.Thanks in advance.Rene

author: Uunoctium
author_rank: Frequent Contributor
timestamp: July 08, 2022, 11:00:49 am
content: described in SM of PM6666(p. 19 in pdf)http://www.ko4bb.com/manuals/2.202.156.65/Frequency_Counter_Service_Manual.pdf(http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=Fluke/Fluke_PM6666)

author: Rene Jansen
author_rank: Contributor
timestamp: July 08, 2022, 11:46:58 am
content: Many thanks, it's a lot of help.
PMJ-02 Handheld inkjet label printer - USB failure - Page 1
Forum section: electronics / repair

author: Phil1977
author_rank: Frequent Contributor
timestamp: April 24, 2025, 09:14:47 am
content: Hi everyone,I have a problem with this label printer:It worked fine for a long time, but since today the USB data connection to a PC is not working anymore. Charging over USB and printing is still perfectly okay, but I can't upload any logos or files to the printer.The embedded system consists of a HI3526 with a removable 2GB-SD card. The SD-card is not readable by a windows-PC.Using the "Restore to defaults"-function of the menu does not solve the problem. I also tried dis- and reconnecting the battery - without success.Has anyone of you other ideas?Thanks a lot in advance!

author: Haenk
author_rank: Super Contributor
timestamp: April 24, 2025, 10:34:20 am
content: Is it possible to replace the microSD-card? I'd certainly try that, it might just be defective.

author: Phil1977
author_rank: Frequent Contributor
timestamp: April 24, 2025, 11:35:50 am
content: The printer does not boot up if the original SD-Card is removed or replaced by a blank card...

author: Haenk
author_rank: Super Contributor
timestamp: April 25, 2025, 05:11:37 am
content: I can offer to copy and/or test the card (we have several U-Reach i9 Gold devices, which allow a 1:1 copy). You'll have to supply a 2GB though, we don't have those anymore... PM me, if interested.

author: Phil1977
author_rank: Frequent Contributor
timestamp: April 25, 2025, 08:26:08 am
content: Thanks a lot@Haenkfor the offer!It seems the "USB-Host"-mode of the device is still working, in other words: If I connect a USB-C-memory to the label printer I can copy files in both directions. I´m 99% sure that until recently it was working also in "device-mode" - but maybe that´s just the curse of a complex interface that sometimes things stop workingFor the short term the problem is solved
PNA boot issue - Page 1
Forum section: electronics / repair

author: jmonette
author_rank: Contributor
timestamp: December 09, 2020, 09:05:12 pm
content: Hi everyone,I have a PNA that I'm trying to fix for a while now. I have an E8358A with the 500MHz CPU. I have a WinXP and W2K hard drive for it that are known functional.My issue is that the PNA doesn't boot. The splash screen of Windows come and stay for a while with the loading bar moving then the screen goes black and stay that way forever. It does boot without any issue in safe mode. Therefore, I'm confident that the basic minimal hardware should be enough for it to boot.It as been on my desk for over 4 months now, and I'm not getting any closer to make it work. The last thing I tried in safe mode is to do a Diagnostic startup and it showed the same behavior. I'm not sure what to do from this point, any ideas?Thanks

author: tonyh88
author_rank: Regular Contributor
timestamp: December 14, 2020, 05:07:37 am
content: and both drive with win XP and win 2K show the same behavior? If yes and it works in safe mode it would point to a driver issue.Is there a graphic card in that unit? Have you tried uninstalling the video card driver while booted in safe mode?

author: jmonette
author_rank: Contributor
timestamp: December 14, 2020, 01:29:12 pm
content: Yes, both drives as the same behavior. I tried to update the video driver, but it's an old chip that is not supported since 2003. I found a driver for, but Windows detected it as older as what was installed on it. I uninstall the driver and installed the one I found. Sadly, it behaved the same.Since it's a proprietary motherboard without any standard PCI connector, placing a dedicated GPU isn't a real possibility.Is there a way to boot in windows using the driver of the safe mode?thanks

author: tonyh88
author_rank: Regular Contributor
timestamp: December 15, 2020, 03:13:44 am
content: Well actually if you just uninstall the driver it should boot with the generic windows driver that's why I was wondering. Maybe try just uninstalling the driver in safe mode and rebooting

author: jmonette
author_rank: Contributor
timestamp: December 15, 2020, 04:33:30 pm
content: You were right! Now it boots!!!Should I try to find a functional driver or is it pointless? Is there any reason why I should install the driver? The video quality won't be much better...Now, there is a new issue! That's the wonder of trying to fix a scrap PNA!Thanks a lot!

author: tonyh88
author_rank: Regular Contributor
timestamp: December 16, 2020, 01:18:28 am
content: Glad to hear that!!The driver was probably corrupt. You could try to find and reinstall a copy of the good one but if it boots and the resolution is fine for you I wouldn't worry too much about it. Fix everything else that is wrong with the PNA andif you still want to update the driver by then you can come back to thisStart a new thread if you have other issues on this unit
Pnp drive section  - Page 1
Forum section: electronics / repair

author: Australia-learn
author_rank: Contributor
timestamp: May 25, 2025, 12:25:26 am
content: Good day. Got a cheap chinese (240v) 30vdc 10a power supply here. Im doing some work in the driver section. There using only pnps here as the drivers (running mosfets). Runs off tl494. Pnps marked 'BA'. I've removed the caps that feed the collector. Anyone know the value of these caps? The ones that came out varied there values wayyyy too much. C48 and C49. Excuse the crap screenshot this site is so damn picky on photos. Cheers 🙂
PoE IP Camera Board needs reset and possible firmware flash - Page 1
Forum section: electronics / repair

author: smk279
author_rank: Contributor
timestamp: September 01, 2025, 03:51:04 pm
content: I haven't been able to connect to this camera so I took the board out looking for a reset to factory defaults jumper but couldn't find it I could also upgrade the firmware while I have the board out but I don't know where to download

author: Swake
author_rank: Frequent Contributor
timestamp: September 01, 2025, 05:10:29 pm
content: Might want to provide some information about the camera itself. Brand, model, things like that.

author: smk279
author_rank: Contributor
timestamp: September 01, 2025, 06:52:53 pm
content: Revotech Mini POE IP Camera HD 3MP Model I706P
Polar T3000 CRT Trace is very dim, even at maximum intensity. Help - Page 1
Forum section: electronics / repair

author: aqibi2000
author_rank: Regular Contributor
timestamp: December 10, 2019, 03:24:16 pm
content: I have a Polar T3000 which has a very faint trace on the CRT.I would like to have some support to adjust the trimmers to the appropriate levels.The unit uses the same tube as the T2000/2500/4000/6000Will take pictures soon when someone chimes in.Thank you

author: aqibi2000
author_rank: Regular Contributor
timestamp: December 11, 2019, 03:04:13 pm
content: Images attached. Blue potentiometer R105 is the Focus adjustment.There is a 1500V line from the voltage doubler circuit in the corner on a separate riser board (large caps and diodes) which I cannot measure since my equipment is only suitable for up to 1kV.
Polar V650 battery not charging - Page 1
Forum section: electronics / repair

author: MrSadman
author_rank: Contributor
timestamp: July 10, 2020, 08:11:23 am
content: Hi,I've got a problem with a Polar V650.Fault description - Unit does not charge when connected to a wall charger.Steps so far:Opened up the unit and the battery had swollen up.Seems like an easy enough fix, just get a new battery and you're good. Unfortunately this is where I'm stuck.I can't find the same make and model of battery anywhere.Browsing the internet, it seems I am not the only one with this problem...Anyone have any suggestions where to find a battery that has the same connector/pinout and measurements?I guess my other option is to hope that the BCS is functional and try to get it off of the battery and swap it to a suitable replacement. I don't enjoy soldering around Li-Po's so I'll leave that as a plan B for now.

author: mikerj
author_rank: Super Contributor
timestamp: July 10, 2020, 09:05:59 am
content: If an exact replacement is not available you'll have to source a cell of the same or slightly smaller dimensions and swap over the battery protection board (if one is fitted). I've had to do this on quite a few older devices.The main dimensions are most likely 44x66mm, but you'll need to get a reasonably accurate thickness measurement. Since the cell is swollen you may have to get this dimension from the housing, e.g. put a piece of modelling clay where the battery sits with some kitchen plastic food wrap either side, temporarily put the device back together to squash the clay and then remove it and measure with some vernier calipers.
Polish tinted display scratches - Page 1
Forum section: electronics / repair

author: xlzslayer
author_rank: Contributor
timestamp: April 05, 2025, 07:46:52 pm
content: I recently got my hands on a used Fluke bench DMM (8808A) and noticed that the external plastic display is a bit scratched. I already have some plastic polish (Novus 3) and was wondering if it would be okay to polish those tinted plastic displays, and if that would bring desired results.The scratches aren't particularly deep, there's maybe only 1 or 2 slightly deep scratches, and a bunch of lighter scratches. I plan on polishing it by hand with a microfiber cloth.

author: inse
author_rank: Super Contributor
timestamp: April 06, 2025, 04:47:26 am
content: The display window may be anti-glare treated which will disappear together with the scratch.You would have to decide whether the scratch or a glossy screen are more annoying.By the way I found it hard to entirely remove real scratches in plastic screens, with polish alone you only round the edges which gives an optical effect.For perfect removal you would have to sand it down and polish afterwards if you dare.Luckily the window in my 34401a was only scratched outside the display area, so I was able to attenuate the visibility with polish

author: C-47
author_rank: Regular Contributor
timestamp: April 06, 2025, 05:40:07 am
content: I note that Novus 3 is the coarser of a 3 part system for removing scratches, you may need to also get the finer grits. For light aircraft windscreens which are Acrylic / perspec a product is Micromesh its used for polishing out scratches and its very good, not sure its available in your area though at a reasonable price.

author: watchmaker
author_rank: Unknown
timestamp: April 06, 2025, 12:00:33 pm
content: I was using watch crystal polish until someone on this board suggested it was much less expensive to use a headlight polish like Mother's. Now I use that for everything.Just clean off with IPA. On all plastic be sure to use cotton cloth. An eyeglass tech finally told me that that products like Lens Wipes will create the micro scratches that cause us to replace our lenses every couple years.

author: richnormand
author_rank: Unknown
timestamp: April 06, 2025, 07:12:00 pm
content: If you tilt the display with a bright light source you can see if it has an AR coating. If it does I would not recommend using the Novus polisher.I several cases I had instruments and LCD camera displays (on the back) that had haze and several surface scratches.I use the Novus 1 clean and shine on the display being careful not to have any dirt left. Then a small amount of Windex to eliminate any grease left.Then apply one of these plastic cover with an adhesive on one side for protection. I found that with the good ones the glue will fill the surface irregularities and eliminate the haze and small scratches.Some suppliers have sheets in various sizes or custom to a device.It is also reversable if you do not like the results, unlike polishing.
Polk Audio PSW111 not working/white noise - repaired - Page 1
Forum section: electronics / repair

author: BertB
author_rank: Newbie
timestamp: December 29, 2023, 02:40:53 am
content: The Polk Audio PSW111 subwoofer I have was not doing well. It would produce white noise with nothing plugged in and basically not amplify (perhaps I could hear a bit of sound, very faint and not base).I found this website and they pointed at two 47uF/63V caps:https://forum.polkaudio.com/discussion/175654/polk-psw111-sub-woofer-heartbeatI ended up getting on the digikeys and getting a number of capacitors (Nichicon of course). Noting polarity I replaced the high voltage input capacitor, a 120uF/63V and the two 47uF/63V and sure enough it now works again.I checked and one of the 47uF/63V caps was out of spec (only 1.3uF, not 47uF). I didn't bother to dig up the cheap component tester for an ESR measurement.
Polk PSW150 Schematic? - Page 1
Forum section: electronics / repair

author: MuseChaser
author_rank: Contributor
timestamp: March 10, 2022, 06:53:14 pm
content: Does anyone have access to one? I called Polk, and they said they no longer had them for stuff that old. Haven't pulled the amp from the enclosure yet. Symptom - powers on, can hear internal relay click, but absolutely no output. Phase toggle switch is immovable for some reason.Thanks.

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: March 12, 2022, 02:30:13 pm
content: You might look for old warranty centers that are still in operation.Jeff
Poor power supply - Agilent E3646A - Page 1
Forum section: electronics / repair

author: mrbook
author_rank: Contributor
timestamp: March 20, 2025, 12:41:15 am
content: Recent e-waste purchase. Got it cheap so not that worried, but this thing is smoked. Looks like the negative rail on output 2 got the brunt of it but there are some burnt traces on the bottom on output 1 side as well…Going to invest a few dollars into it and make an attempt.Currently waiting for some parts to show up.

author: andrewtaylor
author_rank: Contributor
timestamp: March 20, 2025, 08:54:36 am
content: This might be helpful:And of course: Have the schematics right beside your repair desk

author: mrbook
author_rank: Contributor
timestamp: March 20, 2025, 12:35:28 pm
content: Thanks I have watched that video a while ago but rewatched it again and it was helpful to see how he got it running outside the chassis. Will make troubleshooting a bit easier.

author: IanJ
author_rank: Unknown
timestamp: March 20, 2025, 03:34:37 pm
content: A few Agilent power supplies repairs on my channel, here's a playlist.Good luck, and keep us informed as to how you get on.https://www.youtube.com/playlist?list=PLFTNjqbH_TxkiYsF76ttjXmxgQeXewjSQIan.

author: mrbook
author_rank: Contributor
timestamp: March 21, 2025, 12:02:20 am
content: Hi Ian,Been a sub of yours for many years. Thanks for the link to the videos, going to need all the help I can get with this one.Got it all torn apart today and started the clean up process. Here’s the burnt trace from the bottom of the board on channel 1. Looks like most of the visible damage between the negative output and pin 1 of the SCRs at CR124 and CR132. If I jumper the traces I get output on both channels but readings are all over the place.

author: mrbook
author_rank: Contributor
timestamp: March 23, 2025, 09:35:26 pm
content: Little bit of an update. I repaired both traces, replaced the SCRs the traces went to and a small op amp near the SCR on output 2. The good news is channel 1 seems to be working well, all self-tests now pass and the weird voltage fluctuations on both channels have gone away. The bad news is that channel 2 is still not working. When I turn the output on the voltage reads -0.653 volts and UNREG illuminates on the VFD and I don’t seem to be able to adjust the voltage at all. It’s the same readings with and without a load.So some progress. I’m still researching what might be causing the issues on output 2 but if anyone has any ideas let me know.I have noticed 1 LM317 and 1 LM337 getting pretty hot so I’m going down that path currently.
Popping in Harman Kardon Citation Multibeam 700 - Page 1
Forum section: electronics / repair

author: okw
author_rank: Frequent Contributor
timestamp: November 26, 2024, 05:51:19 pm
content: My parents soundbar (H&K Harman Kardon Citation Multibeam 700) suddenly started making a popping sound. It seems to come quite regular a few seconds apart. It doesn't come until a minute or two after plugging in the power.Any ideas what it could be? A bad capacitor?Anyone have a service manual for this?
Porsche Climate Control - Page 1
Forum section: electronics / repair

author: gkmaia
author_rank: Frequent Contributor
timestamp: July 07, 2024, 10:59:49 am
content: My climate control has gone kaputs...The control is based on a C515C microcontroller and interfaces with the CANBUS with a TJA1054. According to the datasheet failure scenarios the 1054 seems to be working properly.The display is driven by a PCF8576. As you can see in the video bellow the unit is able to to drive the display and the car's actuators. However I can't control the temperature.And by looking at the cars wiring is possible to see that all that works is connected directly to the unit, while temperature sensors info has to come from the canbus.Is it an indication that there is no hardware issue with the unit? Most likely lost the capacity to communicate with the canbus?https://www.nxp.com/docs/en/data-sheet/PCF8576.pdfhttps://pdf.datasheetcatalog.com/datasheet/philips/TJA1054T.pdfhttps://www.jakelectronics.com/pdf/datasheets/infineon-safc515c8em-datasheets-1499?product=infineontechnologies-safc515c8em-13112211

author: kripton2035
author_rank: Super Contributor
timestamp: July 07, 2024, 11:37:53 am
content: isn't it simply that you're out of refrigering gaz ?

author: gkmaia
author_rank: Frequent Contributor
timestamp: July 07, 2024, 11:57:45 am
content: Quote from: kripton2035 on July 07, 2024, 11:37:53 amProbably not, because I have a canbus diagnostics tool and the car has no issue. It would show in the can bus if the refrigerant pressure was off.

author: Haenk
author_rank: Super Contributor
timestamp: July 07, 2024, 01:14:26 pm
content: Quote from: gkmaia on July 07, 2024, 11:57:45 amSo you can read the actual outside temperature via OBD?And did you scan for further errors via OBD, the pressure sensor should bring up a reading as well?"No issue" is really of no meaning, the temperature sensor might read -50oC - which will make the aircon stop but will not create a fault.From the behaviour I would expect an error inside the airconditioning system, not in the frontend unit.

author: gkmaia
author_rank: Frequent Contributor
timestamp: July 07, 2024, 08:08:30 pm
content: The OBD I have is a Porsche specific one so it access all areas of the car. And yes I can read at least 20 parameters within the AC system. It is very comprehensive and all parameters related to AC seemed to be within spec. But, will review the parameter to make sure they are in spec and not missing anything.Also, if I scan the car without the AC module connected it accuses the module is missing and it could only know that through the canbus as you can see in the diagram attached there are no ID lines. This supports your theory that the unit is working, communicating with the ECU and the problem is somewhere else.

author: EHT
author_rank: Frequent Contributor
timestamp: July 08, 2024, 11:43:48 pm
content: What about power supply and ground lines in some places? Have you also asked in rennlist to see if there is some common problem on that model, perhaps something with the wiring looms or water ingress
Porsche PCCM+ installation help - Page 1
Forum section: electronics / repair

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: October 12, 2021, 12:28:30 am
content: Does anybody know about the Porsche PCCM+ radio?I have one that I must complete a botched-abandoned installation on.I need the antenna jack colors, a reason why there is no audio no through the speakers no matter what I do in the settings-volume menu.The info on these is limited because the Porsche Gods deem it so.HELP please!

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: November 05, 2021, 07:24:31 pm
content: I managed to get the radio installed even with many unknowns.I got it all hooked up with the accessories provided including the "batwing" panel at the bottom of the console tree.There, the USB and headphone box was mounted on the batwing panel, it cost $70 for the blank!Cutting and epoxying the board without the steel box it comes in, the lengthening the cables as no extension cable is made, resulted in the photo seen below.Next, one has to switch between CAN and AMP audio in the menu.I then try to figure out why the speakers don't work.The solution was found at the very end of a YouTube video which shows the same procedure in the leaked PDF instructions for the PCCM+.The answer, follow the manual. After following the instructions for the audio selection, disconnect power to the radio by unplugging the power cable to it.Then apply the power cable again and the sound magically appears from the speakers.I'm done, it's been 3 months working on this.No help from Porsche as they want you to bring it in and after sacred secret scrolls are consulted, and some $thousands$ later, all will be right.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: November 05, 2021, 07:25:52 pm
content: And finally the rest of the photos.

author: EHT
author_rank: Frequent Contributor
timestamp: November 05, 2021, 11:47:31 pm
content: My car has PCM in it; works with bluetooth etc (even Android!). Not sure what PCCM is.I suggest:(a) ask on Rennlist, there are lots of experts there, if not,(b) find an indy garage who specialise in Porsche. They'll charge half the hourly rate of Porsche and probably fewer hours as well.
Portable speaker - Bypassing automatic zero-detect mute  - Page 1
Forum section: electronics / repair

author: batou
author_rank: Contributor
timestamp: February 17, 2022, 02:28:35 am
content: Hi I've recently acquired a 'Marley Get-togther', a fairly expensive and good-sounding speaker that has Bluetooth as well as analog inputs.The mute-circuitry is way too aggressive though - you can't use it to watch a movie at all, or listen to any music with quiet or silent sections. And it has a lag as it comes out of mute.I took a look inside and found an STA559BW '2.1 channel high-efficiency digital audio system Sound Terminal' (https://www.st.com/resource/en/datasheet/sta559bw.pdf). I believe its doing the muting internally, and this is configurable in a register. I traced back the I2C lines and they go to something that I am assuming is some kind of PIC with built-in flash. Part number SS(i?)95f116.I checked the power supply, power-off and reset lines of the STA559BW and none of them are changing as this thing goes in and out of mute.I think the proper way to disable the mute would be to download the firmware of the PIC (if possible?) reverse-engineer it, but I'm not set up for that and that seems fairly involved. What other options do I have? Would there any easy way to spoof an input signal, without causing audible noise or affecting sound quality?Thanks y'all

author: amyk
author_rank: Super Contributor
timestamp: February 17, 2022, 04:25:19 am
content: The '95f116 is probably a MB95F1xx series MCU which seems to have originally been made by Fujitsu, then became Infineon and then Cypress. If it isn't continuously causing activity on the I2C, you may be able to code your own MCU to take control of the lines and flip the appropriate bits in the config registers to disable the automute after the main MCU is done, or even "proxy" the data and modify the config write appropriately.

author: MathWizard
author_rank: Super Contributor
timestamp: February 19, 2022, 12:53:47 am
content: Is there any external RC timing doing the mute time ? Maybe it's not done that way at all, but maybe.
Portable WHM Test Kit & 712 COMPARATOR  - Page 1
Forum section: electronics / repair

author: Smile2016
author_rank: Regular Contributor
timestamp: August 20, 2024, 06:47:42 pm
content: I recently purchased a Portable WHM Test Kit and a 712 COMPARATOR from eBay. I’d like to perform an operational verification, but it’s nearly impossible without a manual. I’m unsure how to set it up. Does anyone have any old documents, schematics, or anything that could help?
Possible? - skiping mains power circuitry and injecting power after rectifier - Page 1
Forum section: electronics / repair

author: mlindroth
author_rank: Newbie
timestamp: October 29, 2021, 02:08:01 pm
content: Hello all,I'm trying to probe a malfunctioning PCB and would like to power it on the bench without having mains voltage on the board. Is it possible to inject 12V power after the diodes in the full-wave bridge rectifier and filter capacitor?Thanks!

author: bdunham7
author_rank: Super Contributor
timestamp: October 29, 2021, 02:11:02 pm
content: Yes, this is a common way to test boards out-of-chassis or when there is an issue with the mains supply. You do have to know for sure what the voltage is supposed to be and have a current-limited or protected power supply. You can also supply the power before the bridge rectifier if you remove the transformer leads. In any case, you should be careful to first check that the problem isn't actually in the bridge rectifier itself.

author: mlindroth
author_rank: Newbie
timestamp: October 29, 2021, 02:14:10 pm
content: Thanks, I have checked it in place hooked up to mains. The transformer is outputting 12V, and the FWBR is working. I believe that for some reason the microprocessor is not outputting PWM pulses, or not supplying 10V to the blower motor.

author: fzabkar
author_rank: Super Contributor
timestamp: October 29, 2021, 08:09:55 pm
content: One possible, remote caveat is that some circuits monitor the frequency of the supply to synchronise their real time clocks or to detect zero crossings for TRIAC switching.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: October 29, 2021, 08:42:15 pm
content: Yes, and there is also the case where the circuitry monitors the AC supply, so if this suddenly disappears, there is a "fast off" circuit that mutes the audio before Big Bangs blow the speakers.
Potentiometer Identification (Albrecht AE4500) - Page 1
Forum section: electronics / repair

author: DefinitivVair0
author_rank: Contributor
timestamp: February 16, 2025, 03:55:52 pm
content: Hi there,I am trying to repair my old Albrecht AE4500 CB-Radio with a broken potentiometer. The potentiometer is for power and volume on the inner, and squelch on the outer knob.Problem is, I can't identify what kind of potentiometer this is. I also can't find anything in the schematics (http://www.elektronikjk.pl/telekomunikacja/cb_radio/cb/ALBRECHT-AE4500-3.pdf), pcb or part itself. Here are some pictures of the potentiometer:https://postimg.cc/gallery/WvtnP29Can someone identify this part or maby an alternative?Thanks in advance

author: Haenk
author_rank: Super Contributor
timestamp: February 16, 2025, 06:25:58 pm
content: the schematic is very low res, Volume might be 50k (A), Squelch 10k (B)(it's bottom middle in the schematics, VR1 & VR2)

author: DefinitivVair0
author_rank: Contributor
timestamp: February 16, 2025, 06:35:42 pm
content: Quote from: Haenk on February 16, 2025, 06:25:58 pmIs that kond of potentiometer a common thing you can buy or is it something wildly specific? For example could I just buy a new potentiometer with those values?

author: Haenk
author_rank: Super Contributor
timestamp: February 16, 2025, 06:55:12 pm
content: If it is damaged and unusable, you could open the two cases and measure the resistive trace, also check for log or lin.It might be hard or impossible to find a direct replacement, it is probably easier to just drill another hole and use 2 separate potentiometers.

author: Harry_22
author_rank: Frequent Contributor
timestamp: February 16, 2025, 07:10:22 pm
content: https://www.ebay.com/itm/134118081391

author: DefinitivVair0
author_rank: Contributor
timestamp: February 16, 2025, 08:37:59 pm
content: So. I measured everything and managed to "fix" it. The inner one was indeed 50kOhm (measured 48) and the outer one 10kOhm (measured 8,4).The problems were:The power switch was offset by 180° to the volume slider (when on it was allways full volume) -> I just turned it back to where it should have beenThe slider on the volume potentiometer was not making proper contact with the resistor -> I bent the lock for the inner axle so that it was pulling the slider stronger onto the resistorBoth of those problems were probably my fault because of a prior try to disassemble the front panel.I'm gona try to get the volume slider to make better contact but I don't want to risk breaking off the thin contact wire completely :/
Pots Wanted - Page 1
Forum section: electronics / repair

author: TonyBe
author_rank: Regular Contributor
timestamp: November 13, 2020, 03:50:43 pm
content: Hi Folks,once again I really hope that you can help me out with this.I'm working on a repair of an ITT Metrix GX240 Generator/ Counter Instrument. All the big issues could be resolve just fine,.. even without a schematic.Sadly I need to change the pots since one is completely broken (PCB with the graphite traces is snapped), and all the others have such a bad feeling to them that i can not resist to put some fresh ones in there.Now the Problem: after browsing through DigiKey, Mouser, TEConn, Piher, Amphenol and Bourns, i cannot found a single Pot that would satisfy the requirements given.Does anyone of you have seen Pots like these and maybe can serve a distributor or manufacturer so that i can search for the ones that i need?Here are the culprits:Several of the Pots are of this type. 4mm Shaft. Some about 37mm shaft length (including the threaded section), and some with about 20mm length.[see=pot(4).jpeg]The important and weird thing is the metal cage, that gives the pot enough strength since the pots are not screwed onto the frontpanel. They just stick out. Note the solder-post of the cage which are in front of the contacts,.. never seen it that way around before.Shaft is attached like this:[see=pot(3).jpeg]Now the ones that are really special:[see=pot(2).jpeg][see=pot(1).jpeg]These are pots with a DPDT Switch, which is actuated by push-pulling the shaft. All pcb print solder mounted.Sorry for the crude pictures.Does anyone of you can give me some advice where i can get those parts?If not directly: maybe you can add some Manufacturers to the list above so that i can browse them?Thank you in advance,kind regards from germanyTonyEDIT: Fail.. i just find out, that the previous owner of the instrument have reverse assembled the pot in pic "pot(4).jpeg",.. so well: the Problem with the strange position of the solder posts of the cage is solved at least,.. anyway: don't know where to find those..Sorry for the confusion!

author: bob91343
author_rank: Super Contributor
timestamp: November 13, 2020, 07:25:09 pm
content: I have some pots like that, salvaged from who knows where. Maybe an old audio mixer, not sure. But they were a popular type a while back. Who made them?
Potter & Brumfield Baby! - Page 1
Forum section: electronics / repair

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: July 24, 2024, 10:48:41 pm
content: I guess they may not break much. But what beauties they are!Behold!https://www.ebay.com/itm/255409247109?itmmeta=01J3KEG8R76Q545SCPF92SFK3AP&B's history may be traced to 1932, when Elbert E. Potter and Richard M. Brumfield established a small manufacturing business in their hometown of Princeton, in southwestern Indiana. At the time, the two young men were employed at the local Hansen Manufacturing Company, which produced small motors for clocks. There, Potter was a toolmaker, and Brumfield, who had studied engineering at Purdue University, worked in the design and drafting department and also operated a die cast machine. During 1932, however, both men were often out of work, as the company was forced to lay off large numbers of its employees in order to withstand the effects of the Great Depression. During these periods of unemployment, Potter and Brumfield decided to try developing a business of their own.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: July 26, 2024, 01:24:24 pm
content: Why are these switches so expensive?......is it because they are old and rare?or because they have phenomenal specifications? Uncle Google doesn't tell me much, other than they are available on E-Bay?

author: Stray Electron
author_rank: Super Contributor
timestamp: July 26, 2024, 03:23:28 pm
content: I tried to buy some of the P&B Time Delay relays in the late 1970s and they were about $40 at that time! And they weren't the fancy ones like these. They were just a fixed delay time. I needed about 8 or 10 of them but when I found out the price, I gave up on that project!But I've seen a lot of very nice P&B Time Delay Relays in mil surplus equipment over the last 30 or so years and at $159 each, now I wish that I had saved them and put them on E-Greed!

author: TimFox
author_rank: Super Contributor
timestamp: July 26, 2024, 04:16:06 pm
content: I bought some P&B CUF-42-70120 relays from a surplus dealer years ago.They use a mechanical DPDT relay ("plate relay" type) operated from 120 VAC through a unijunction-transistor R-C timer with external timing resistor.I had a few of them fail due to the tantalum timing capacitor, which I replaced with a lower value higher voltage unit that fit into the enclosure.When I tried to purchase more, the original dealer was out of stock and the new price was much too high for me.
Potting removal options ?  - Page 1
Forum section: electronics / repair

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: January 28, 2024, 10:21:48 pm
content: Got another repair issue - a potted circuit board , this one has off white color .But would like to hear options , maybe some types more removable , and not, ;( ?

author: Haenk
author_rank: Super Contributor
timestamp: January 29, 2024, 09:03:33 am
content: Is it silicone based, or more like rock-hard stuff?

author: jonpaul
author_rank: Super Contributor
timestamp: January 29, 2024, 10:43:27 am
content: photos?

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: January 29, 2024, 07:15:29 pm
content: Ok have a picture , it is hard - with a little flex , but can not make a mark with finger nail .It is part of a Dewalt 60volt air compressor .My guess is that I turned on with max pressure in tank 120lbs , maybe the high current darw of trying to start against full pressure cause a failure .Tried another battery [ incase the BMS turned off the other battery ] still not working .Looks like a 3 phase motor with control board [ pictured ] between motor , battery , switch & pressure switch --- I did jump the pressure switch incase it was cause " no run " .So figured fault in potted board .Thanks for refplies

author: jpanhalt
author_rank: Super Contributor
timestamp: January 29, 2024, 07:52:14 pm
content: People who clean up fossils do that all the time -- and I mean years of picking. Good luck. There really is no solvent for epoxy, silicone, and numerous other polymers. Removal requires melting, if possible, or denaturation (i.e., chemically burning it, etching), or physically picking it off. Some solvents, e.g., methylene chloride, may make it more flexible so it comes off in larger pieces, but that is still a lot of work. Melting is not practical for epoxy and silicone.

author: inse
author_rank: Super Contributor
timestamp: January 29, 2024, 08:15:00 pm
content: Recently I depotted a high voltage module that I destroyed by drawing arcs.I put it into the oven at 150 degrees centigrade- the compound could easily be scraped off but it smelled nasty.After repair I re-potted it with clear epoxy.Give it a try, nothing to lose.

author: jchw4
author_rank: Regular Contributor
timestamp: January 30, 2024, 05:33:07 am
content: I had some funny experience with that:https://www.eevblog.com/forum/reviews/ikea-ledare-teardown/msg4197535/
Power Bank Repair Help - Page 1
Forum section: electronics / repair

author: thushdt
author_rank: Newbie
timestamp: October 11, 2022, 05:23:15 am
content: I have Remax 20000mAh power bank with not charging problem, when i connect carger 16pin ic getting hot, i try to replace ic but i couldn't find, ic number is "481C00CA", please help me to find equal ic. thank you, sorry for my bad english

author: mariush
author_rank: Super Contributor
timestamp: October 11, 2022, 06:11:05 am
content: Unfortunately slim chances you're gonna find the exact chip used, it's most likely some chinese power bank chip (battery charger + integrated dc-dc converter to convert battery voltage to 5v) so if you're super lucky maybe you'll find it lcsc.com by browsing chips in those categories and picking ones with same footprint