hybridfree/eevblog-posts huggingface dataset:
PCB Repair (lost SMC cap) - Page 1
Forum section: electronics / repair

author: skymont
author_rank: Newbie
timestamp: February 04, 2025, 10:40:42 pm
content: I accidentally knocked off a capacitor while plugging the power cable back in, my hand slipped and the tool smacked off the cap, Im not too familiar with sourcing new parts, I know its a 603 size, 150uf ceramic capacitor, and the battery is 7.74v. the capacitor is right after the battery cable so its definitely getting 7.74v.can anyone help me find a replacement capacitor? dont care if I have to spend $50 on a book for smcs

author: ataradov
author_rank: Super Contributor
timestamp: February 05, 2025, 12:49:31 am
content: 150 uF capacitors don't exist in 0603 package. And how do you know the value? It is typically not printed on the ceramic capacitors.

author: skymont
author_rank: Newbie
timestamp: February 05, 2025, 03:33:22 am
content: thats what the muiltimeter read, fluke 87. I just double checked like 10 of them, they all read 148-152 uf.after double checking the sizes, micrometer measured .074 by .037 inches, which is imerial 603 or metric or metric 1608

author: ataradov
author_rank: Super Contributor
timestamp: February 05, 2025, 04:07:08 am
content: Are you measuring in-circuit? That measurement is meaningless.

author: gamerpaddy
author_rank: Regular Contributor
timestamp: February 05, 2025, 10:31:39 am
content: probably just a decoupling cap, slap in a 100nF 0603 in there and call it good.you can even fit a 0805 in a 0603 footprint.ive repaired multiple wifi routers with 100nF caps on the dc-dc converters that failed until i had the idea to measure a good one to see if its even the right value .. it should be 2.2uF...oopsbut nevermind it still worked just fine on all of them..

author: skymont
author_rank: Newbie
timestamp: February 05, 2025, 09:34:57 pm
content: I found out the problem, its a me problem, clearly ive lost my mind. obviously is possible to have them wired in parallel on a circuit board, dont know why I thought I could get an accurate measurement off the board lol.aaaaanyways, any recommendations on where to buy the part after I un**** my brain and get around to pulling one off for proper a measurement?also, does voltage rating matter a lot? is it safe to go over but not under? do I need to at least be close but above?also how far off my measurement capacitance wise is accaptable?

author: ataradov
author_rank: Super Contributor
timestamp: February 05, 2025, 10:17:55 pm
content: There is a good chance you don't need that cap at all. But generally pick anything with a higher voltage and basically any capacitance in a 1-10 uF range if that makes you feel better.
PCB Repair Kits - Page 1
Forum section: electronics / repair

author: Laval
author_rank: Regular Contributor
timestamp: June 21, 2024, 12:37:28 am
content: I had to repair a couple of PCBs in the past few months (mostly lifted SMD pad and a cut trace). They were not particularly difficult repairs but it's something I don't do very often so I guess I'm not used to it. After a quick search I came across PCB repair kits sold by various manufacturers (PACE, Circuit Medic). The thing is, they are very expensive and I'm not sure they are really worth the money. They may do a nice job though. So my question is: has anyone ever used such tools and if so, are the results any good ?Just a couple of example.https://www.circuitmedic.com/https://www.testequity.com/product/612PT077-6993-0077?gad_source=1
Peak Atlas LCR40 - Page 1
Forum section: electronics / repair

author: tarsus
author_rank: Newbie
timestamp: April 01, 2020, 09:10:15 am
content: Hello, I have a Peak Atlas LCR40 which has not been used for some years. The battery was removed some years ago and i have put a new battery in but the screen remains blank. I there anything that i can do. It was working fine some years ago. Thank you for any advice.

author: giosif
author_rank: Frequent Contributor
timestamp: April 01, 2020, 10:03:18 am
content: Maybe the unit still turns on but the LCD is either not working or contrast needs adjustments.Try turning the unit on and looking at the LCD from different angles.

author: tautech
author_rank: Super Contributor
timestamp: April 01, 2020, 10:08:11 am
content: Quote from: tarsus on April 01, 2020, 09:10:15 amWelcome to the forum.Peak Atlas are members here and they started this thread:https://www.eevblog.com/forum/buysellwanted/special-offer-to-eevblog-forum-members/Their contact details are in this post:https://www.eevblog.com/forum/buysellwanted/special-offer-to-eevblog-forum-members/msg2785626/#msg2785626
PeakTech 2025 multimeter shows 330mV after power on - Page 1
Forum section: electronics / repair

author: maelh
author_rank: Regular Contributor
timestamp: October 31, 2022, 05:42:39 am
content: Hello,My PeakTech 2025 multimeter shows about 330mV after I power it on (and set it to volt measurement), with and without leads attached.It very slowly goes down to a lower value, when I short out the leads this happens much faster (than without shorting the leads) and reaches 0mV. After separating the test leads it shows some minor mV variations as you would expect from environment noise.What could be the reason for this initial power up voltage?I already exchanged the fuses, just in case they might have been the issue.Is there something relatively simple I can check to find the cause of this behavior?

author: mcinque
author_rank: Unknown
timestamp: October 31, 2022, 11:49:35 am
content: Does it change the symptom in DC or AC mode?Does this initial issue happen also in other modes (ohm etc.)?

author: maelh
author_rank: Regular Contributor
timestamp: November 01, 2022, 07:15:06 am
content: AC has less resolution so it's hard to tell.Seems to be a bad contact issue.When I turn the dial from V to Ohm usually it shows 0 Ohm, in seldom cases it was also showing significant resistance.But usually when I go from the Ohms setting to the V setting it has a value of a few mV only, as it should.You can see how it quickly goes from 300 or 600mV to almost zero almost instantly.So I think it's a bad contact/issue with the dial.Though when I leave it on the volt setting, the voltage slowly rises, so it's probably a bit more complex.The COM plug solder joint is broken, I will fix it and see if it makes a difference.

author: electr_peter
author_rank: Unknown
timestamp: November 21, 2022, 01:20:00 pm
content: What is PeakTech 2025 input impedance on different voltage ranges? It could be that mV DC range has high (~1-10 GOhm) impedance and may show peak of the range due to offset currents (or some stray charge).Such is the case with Amprobe AM-240 DMM. Turning knob OFF to DC V shows 320mV on 400 mV DC range (this range has high input impedance). 320 mV initial offset (or input "charge") disappears after range change, function change, etc. It is not an issue or problem, just a design artifact.
PeakTech 4120 generator failure - Page 1
Forum section: electronics / repair

author: ferdieCX
author_rank: Regular Contributor
timestamp: October 26, 2023, 09:06:04 pm
content: Hi to all,In the university where I teach, we have a PeakTech 4120 that is failing to properly startup.It is a chinese product that probably sells under other brands. I have seen a two channel model rebadged as TektronixDoes any one of you have any technical information or clue about this device ?Thank you in advance

author: coromonadalix
author_rank: Super Contributor
timestamp: October 27, 2023, 04:49:05 pm
content: could be his one ?In their 1000 seriesAFG1062must be similar to the AFG1022 series ?? but tek on their site have multiples warnings of not messing with the wrong modeldo not flash on 1062 etc ...Anything can be done under the hood, change the front panels pcb ... remove some buttons etc .... rebrand it and voila ?can you open the case and show us any pcb markingswith free registration you have acces to their FW but no 5 Mhz model as far as i knowdownloaded their 1022 fw1.211.221.231.241.27

author: coromonadalix
author_rank: Super Contributor
timestamp: October 27, 2023, 05:00:32 pm
content: reserved 1

author: coromonadalix
author_rank: Super Contributor
timestamp: October 27, 2023, 05:01:28 pm
content: reserved 21.27Maybe you can or someone else can extract the boot filesor help youis it under warranty ??have you contacted Peaktech ??

author: The Soulman
author_rank: Super Contributor
timestamp: October 27, 2023, 05:18:28 pm
content: It's not a tek, it's a Owon, likely "inspired" by the tek design.https://www.owon.com.hk/products_owon_2-ch_arbitrary_waveform_generator_without_counter

author: ferdieCX
author_rank: Regular Contributor
timestamp: October 28, 2023, 01:35:34 am
content: Although it was almost never used, the instrument is about two and half years old, so no warrantyI opened it, and it is not very service friendly.You have to dismantle it almost completely to gain access to the board.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 28, 2023, 01:45:38 am
content: wow what a strange setupan arm cpu moduleyear 2010 is that itmaybe some Owon FW updates ??thread of it herehttps://www.eevblog.com/forum/testgear/owon-ag1012f-arbitray-waveform-generator/you see the pcb hardware ... only thing i see, there is a 3 pins holes in row and we see TX RX on them, maybe some console port ??
PeakTech 6225 Lab PSU with a drift problem - Page 1
Forum section: electronics / repair

author: YadiYada
author_rank: Contributor
timestamp: September 10, 2019, 09:37:44 am
content: I set this PSU to a voltage (tried different starting points: 5V, 12V, 15V or 30V) and a load of 200mA or 2A.The originally set voltage drifts down by about 120mV over the course of 20-30min or so. I have two of these PSUs and they do the same.Any clever ideas on how I could "fix" that? Including schematic for reference (I know the schematic shows MCH-K305D but that seems to be the OEM's).

author: ArthurDent
author_rank: Super Contributor
timestamp: September 11, 2019, 10:21:16 pm
content: The schematic you show is not for the actual power supply but just for the metering section of the supply. The two leads that go from CN0 on the top left then down between the V/A metering sections are the inputs to the meters that would connect to the sensing area of the actual supply which isn't shown. There should be more schematics.

author: YadiYada
author_rank: Contributor
timestamp: September 18, 2019, 04:24:18 am
content: The second page of the attached PDF is showing the main diagram.
Peculiar case of R&S SMP03 - Page 1
Forum section: electronics / repair

author: CrazyTiger
author_rank: Regular Contributor
timestamp: January 28, 2024, 11:49:48 pm
content: Hi All,I was passed down a scrapped R&S SMP03 with failure written down as YFOM failure during internal Cal, somewhere around Mid November last year. When I first got the unit. The instrument was able to pass the internal adjustment, level and frequency were spot on all the way to 27 GHz.End of December 2023. I moved all my instrument to a temporary rack, as i was doing the flooring at my room. During this time, to save space on the rack, all the instrument was stored on its side instead of its normal resting position. Mid January I started to move back things and started to power up instruments. This time the SMP03 came up with YFOM failure, FM coil warning.WARNING 134 FM input of YFO module overdriven;ERROR 180 Calibration failed; YFOM: pretune;So I started opening up the instrument and my suspect was the FM coil of the YIG oscillator itself.The instrument levels were still good, but the frequency was off by around 60MHz. A dead FM coil would lead this, as the main coil handles the coarse setting and FM coil will do the fine adjustment. According to the service manual the FM coil should measure somewhere around 1.5 ohm, mine was measuring 0.5 Ohm(not sure if the manual is correct on this). So my theory was a shorted FM coil could do it. A shorted YFOM coil will draw higher current, so the warning made sense for sure. Removing the control voltage of the FM coil, took out the warning. Further proving the FM coil is indeed over driven.But still there was the case of why the instrument worked when i received it. So i inquired how the instrument was stored in the first place. Prior to error, the instrument was in storage for long sitting on its side. So when they tested, it has failures. Then it was awaiting to be scrapped on its normal position before it came to me. Which made wonder if I rest it flat, would that fix it. So the entire last week it was siting on its default position. Today morning I powered it up. It passed all internal calibration and frequency is spot on. So seems like God of Gravity did some magic.I could live with this, but a failure like this eventually will be permanent at some point. I tried to very gently knock the yig, to see if that changes the state, seems like it does nothing. I am yet to measure the fm coil resistance again. Another post by member in the forum measured about the same as me, but seems like he is facing same problem like mine. Any ideas?https://www.eevblog.com/forum/testgear/rs-smp02-err233-ypll-unlocked/

author: m k
author_rank: Super Contributor
timestamp: February 01, 2024, 11:17:51 am
content: Tilt it only a bit and see what happens.Not very effective if you must wait weeks before next set.Maybe it's a secondary thing.There are sort of heavy parts and pcbs are sort of wide.My experience is from lower frequency things but a connection problem can be *very* delicate.
Pedelec battery BMS - Page 1
Forum section: electronics / repair

author: HansGruber
author_rank: Contributor
timestamp: September 22, 2021, 07:57:08 am
content: I am trying to repair this battery for a pedelec:https://www.batteries4pro.com/en/Mobility/electric-bike/3,17085-battery-36v-145ah-yamaha-winora-y280-type-li-ion-x-haibike-sduro-3052351243985.htmlThe battery is from a colleague and he told me that the battery gauge LEDs always indicates that the battery is fully charged. After inserting the battery, the pedelec does not accept it. That's all the information that I have.After opening the thing up I saw something very obvious, at the 10S balance charge connector the two highest voltage rails shorted at the connector. Removing the cable destroyed the connector since it was secured with some goo, but it's donzo anyways.Here is the BMS without my comments:https://imgur.com/a/y9eDvYdPlease look into the image with my comments here.My plan is to completely remove the connector and solder the cables directly to the B1-B10 testpoints. I measure the individual voltages of the 10S cable, I've noted it in my comments. Can someone tell me if the cells are still good with these values ? It's 37,8V for a 36V battery. I've also measured all the powerrails I could find. They all seem to be okay 13V, 5V, 2.5V. The LED gauge shows 2/5 LEDs (now, after restarting it) for 37,8V with disconnected 10S cable, is that plausible ?My biggest concern is that the internal battery voltage is 37,8V but I only measure 15,5V on the connector to the pedelec. There is also a communication line between the power lines. Will it negotiate the voltage with the pedelec ? If not, I am not sure what could cause the voltage drop. Maybe someone has better knowledge how these things work.
pedestal fan ALL 3 TRIACS FOR LOW, MED,HI . all on @ same time. start cap ok.  - Page 1
Forum section: electronics / repair

author: Pressing multilayers Do I
author_rank: Newbie
timestamp: February 24, 2024, 04:52:44 am
content: ALL 3 TRIACS FOR LOW, MED,HI . all on @ same time. start cap okmotor shaft free. motor does not turn at all when fan on.ic ok it is only commanding 1 triac.I am yet to pull triac and test.Any thoughts, thanks.
Peekel CA 252 carrier frequency amplifier - Page 1
Forum section: electronics / repair

author: Strand17
author_rank: Contributor
timestamp: July 16, 2020, 08:39:57 am
content: Hello,At work we have several CA 252 carrier frequency amplifiers (Trägerfrequenzverstärker) and some of them are misbehaving occasionally. We have the “D” and “F” options, so it is the DCA 252-F to be precise. For no apparent reason the selection of the amplification range can change from the one selected with the knob to a different range. Unfortunately, the fault is intermittent and I cannot provoke it to happen.Peekel Instruments has closed business and none of the related companies I have contacted wants to service CA 252’s or have any technical documentation on them.Does anyone know where I can find schematics for the CA 252 amplifiers? Recommendations of any repair companies in Germany or elsewhere in Europe which can service our CA 252’s would also be highly appreciated.Thanks in advance!Jonas
Peg Perego Thomas 6v ride on train board - Page 1
Forum section: electronics / repair

author: RS200
author_rank: Newbie
timestamp: January 02, 2021, 06:26:16 pm
content: HiIn need of some help.I have an old ride on kids train and have decided to get it out for my granddaughter to use, but after connecting a new battery it doesn't work. I took the train apart and powered the motor direct and this works so i pulled the circuit board (pic attached) to see if i could see anything obvious. Are the 2 transistors to at the top right of the red plug supposed to get roasting hot?Any help would be much appreciated as i'm no electronics wizz and these parts are now obsolete.ThanksDan

author: CJay
author_rank: Super Contributor
timestamp: January 02, 2021, 06:29:59 pm
content: Quote from: RS200 on January 02, 2021, 06:26:16 pmPost a pic of the track side of the board and give us a clue what connects where? (It should be pretty obvious if we can see the back of the board but it might be useful)l?I don't think the transistors should get hot.

author: RS200
author_rank: Newbie
timestamp: January 02, 2021, 06:34:14 pm
content: Thanks for the reply. Pic or tracks attached.

author: CJay
author_rank: Super Contributor
timestamp: January 02, 2021, 07:32:23 pm
content: OK, bad news, the black blob is an IC, if that's gone then you may be out of luck.The transistor marked Q2 seems to be getting *really* hot by the look of the solder on the pads, it controls the relay.I'm guessing this thing only does forward unless there's a switch elsewhere to select reverse.Have you got a multimeter and can you solder?If you can desolder one end of D5 I think you might find it's gone short circuit.Do not run the board with it disconnected.

author: RS200
author_rank: Newbie
timestamp: January 02, 2021, 08:37:53 pm
content: Yes i can solder and have a multimeter, how do i check for a short on the D5 resistor?

author: RS200
author_rank: Newbie
timestamp: January 02, 2021, 09:42:44 pm
content: I tested the diode (D5), after watching a youtube video and it works ok.

author: Meteor40069
author_rank: Newbie
timestamp: February 02, 2022, 02:16:27 pm
content: New member hereJust been asked by a friend to repair one of these. Sounds and light work but not the motor.After checking all the obvious things (battery, wiring, switches, etc.) I had a look at the PCB. No signs of overheating but I found the relay not operating because Q2 was open circuit.Original was an MPS8050. NPN 1.5 AmpNearest I had was a BC338 0.8Amp, but with reversed pinout, EBC instead of CBE.Fitted that and now the motor runs (but the switch on the top of the cab seems a little intermittent)Just hope the BC338 survives, but it's only switching the relay. I didn't measure the relay coil but would expect about 100mA
perfecting a replacement part for the HP 1727A/1715A oscilloscope - Page 1
Forum section: electronics / repair

author: Alex_Baker
author_rank: Frequent Contributor
timestamp: May 29, 2022, 05:23:27 pm
content: Hello everybody.This is a continuation of the long saga that is my 1727A storage oscilloscope from HP. As it stands everything is in pretty good shape except for the vertical output IC, which is a proprietary IC from HP and is thus likely unobtainable, though if anybody has one they could sell, let me know. Long story short I am starting this topic to perfect the replacement circuit for the aforementioned IC, all relevant pictures will be linked at the end, including the circuit schematic.To start out with I just used a couple of IRFZ44N mosfets that I already had, and they yield great results up to 150kHz. Beyond that the amplitude of the trace on the screen starts to decrease(and distort slightly), and by the time I max out my signal generator at 5MHz, the trace is pretty small. So what would cause that to happen? Are the Z44N fets not able to turn on all the way at that speed? Any insight would be appreciated.

author: bdunham7
author_rank: Super Contributor
timestamp: May 29, 2022, 05:30:55 pm
content: I'm going to guess that the circuit driving the original chip doesn't have a low enough source impedance to drive the gate capacitance of your MOSFETs at high frequencies. You probably need another stage.

author: Alex_Baker
author_rank: Frequent Contributor
timestamp: May 29, 2022, 09:19:00 pm
content: The IRFZ44N that I used is supposed to have a max gate charge of about 63nC, and I am aware that the Z44N is no dainty mosfet. The mosfets that the original designer of the circuit used was something close to the STD16NE, which is supposed to have a max gat charge of about 32nC.how much difference do you think that would make? I will do some testing to see if I can come up with some numbers, I also attached the original HP schematic of the vertical output board, which I should have done on my last post.
Perseus SDR receiver, errors.. internal, firmware, rate and others.  Solved - Page 1
Forum section: electronics / repair

author: Wim13
author_rank: Frequent Contributor
timestamp: September 24, 2020, 03:39:30 pm
content: I share this solved problem, perhaps someone is looking for the same issue...I have a Perseus SDR receiver for already 7 years, worked al these years perfect.But last months it worked sometimes not, all kind of random software errors, like internal error, firmware not loaded, bit rate,windows sometimes did not recognized the USB device, reported unknown device.Spend a lot of time with reinstall software,drivers etc...nothing worked,The strange tihing was that sometimes it worked well for an hour.Finanal, i found the error, it was the original power adapter, the elco's inside after 7 years....The power adapter gave only wierd 4 Volt , has to be 5 Volt...Replacing the power adapter for an other 5 Volt 1 Amp (600-700 mA for the perseus) solved all problems.At first I did not suspect the power adapter, because it powered correct up, and sometimes it worked oke,all errors looked software related.
Perth WA - Instrumental Repairer for an Audiometer? - Page 1
Forum section: electronics / repair

author: DMoyle
author_rank: Newbie
timestamp: March 30, 2024, 07:06:55 am
content: Hi all!Wondering if anyone can point me in the right direction for a Perth electronics repairer?I have an Otometrics audiometer that appears to have a power supply issue—it turns off and reboots randomly, particularly when producing a tone.It is not critical if it is repaired or not but hoping to learn through the process more than anything else.Any info is appreciated!Cheers David

author: David_AVD
author_rank: Super Contributor
timestamp: March 30, 2024, 08:50:19 pm
content: There looks to be a few in the Perth region.This oneseems to have good reviews.
PES51 repair - looking for a suitable glue - Page 1
Forum section: electronics / repair

author: mazurov
author_rank: Frequent Contributor
timestamp: January 29, 2022, 12:52:18 am
content: After 17 years my trusty soldering iron became loose in a typical place (see picture). I'm trying to find a glue that:1. Heat-resistant to ~200C2. Bonds well to Bakelite3. Bonds well to steel4. Available in the USABack in Russia I would use the product called БФ-2, it covers 1-3 but since it's flammable I'm not sure I can send it via mail. It's 98% PF resin, 2% PVB. Does anyone knows about similar product available in the states?Thank you!

author: jdragoset
author_rank: Frequent Contributor
timestamp: January 29, 2022, 01:16:54 am
content: https://www.pcepoxy.com/products/permanent-repair/pc-superepoxy/

author: pqass
author_rank: Super Contributor
timestamp: January 29, 2022, 01:26:10 am
content: You could wedge a few strands (pulled from standed wire) between the handle and the metal, push the two together snuggly, then cut off the excess.

author: jpanhalt
author_rank: Super Contributor
timestamp: January 29, 2022, 01:34:03 am
content: Does this fit that description of PV (aka novolak) and PVB ( aka polyvinylbutyral ):https://www.sbhpp.com/products-applications/catalog/item/fers-t840-40%3Fcategory_id=6.htmlI am sure there are others. Google "formaldehyde resin glues" may find something similar. They were used widely in wood boat and aircraftconstruction.Edit: As for that repair, your application does not appear to require much strength. Loctite/Henkel make a line ot adhesives that are sold to keep threaded fasteners from coming apart ("lock tight nuts"). Some are rated for high temperature. I believe what we called the "green" version will work on engines that get quite hot.
PET 2001-8 Repair: Bug in Schematic? - Page 1
Forum section: electronics / repair

author: NivagSwerdna
author_rank: Super Contributor
timestamp: April 12, 2020, 12:21:00 pm
content: I've just bought a non-working Commodore PET 2001-8Looking at the schematics....http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/pet/2001/320008-2.gifI'm trying to work out the decoding for RAM chips I2 and J2.... I think there might be an error on the schematic... specifically I think pin20 of both I2 and J2 should be nBA10?If anyone is familiar with this bit of vintage tech I would appreciate a suggestion as to a forum where I could ask my question.Thanks in advance

author: Andy Watson
author_rank: Super Contributor
timestamp: April 12, 2020, 02:18:33 pm
content: I can't see a source for nBD10 on the diagram - pretty sure it's a typo. J2 is labelled correctly. Pin 20 is a positive chip-select - I would expect a positve/true BA10 to select for the range 400-7ff.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: April 12, 2020, 04:03:43 pm
content: I'm now 99.999% sure it should be BA10.Thanks
Pevono Power Supply, common failure, how to repair. Upgrade discussion - Page 1
Forum section: electronics / repair

author: JBurdman7
author_rank: Newbie
timestamp: November 16, 2020, 10:48:45 pm
content: I'm referring to the Pevono PS305 line of budget bench power supplieshttps://www.amazon.com/Pevono-Digital-Adjustable-Switching-Regulated/dp/B076TMJB35/ref=sr_1_1??tag=parts099-20, also sold as "Sky TopPower" STP30* modelshttps://www.amazon.com/Adjustable-Switching-Regulated-Alligator-Spectrophotometer/dp/B07GCJ5QHF/ref=sr_1_1?tag=parts099-20and the 4 digit / 60V / 10A variants. Before people complain about my cheap PSUs, I also have an Agilent E3631A for when I care to send the very best, which, TBH, is not all that often. I use two Pevonos pretty hard.The Pevono units have a major problem with the STP75NF75https://www.st.com/resource/en/datasheet/stb75nf75.pdfoutput transistor shorting. I have fried the output MOSFET on one or the other unit every year so far. It's easy to do. I suspect that just going in to current limit while set to the highest voltage can kill them but I have not tempted fate to test my theory. At least the safety kicks in and kills the output. 12VoltVids on YouTube covers the repair hereThe transistor is right on top so repair could not be easier.The diagram for the STP75NF75 shows a body zener. I don't know the Voltage of it. I was wondering if anyone here had a suggestion as to what could potentaially be added to help increase the life of these MOSFETs. Perhaps a power diode to shunt any reverse connections. Maybe a 45ishV zener external and in parallel with the body zener in case an inductive spike is coming from the unit itself? I have a 45V zener but it is tiny and perhaps adding that would just be asking for trouble. There are 40VBO BJTs as per Kangaroo Dave's shunt suggestionbut they run $12 each. I don't see that making sense. While downtime is annoying, the STP75NF75 can run a buck each from some suppliers.Any thoughts? Please share.

author: akimpowerscr
author_rank: Regular Contributor
timestamp: November 17, 2020, 09:18:33 am
content: Welcome to the forum.Don't you think it would be necessary for you to provide the diagrams of this power supply so that your questions can be answered?

author: JBurdman7
author_rank: Newbie
timestamp: November 17, 2020, 07:14:40 pm
content: Quote from: akimpowerscr on November 17, 2020, 09:18:33 amI'd be glad to if I had them. It's just a cheap switching supply. This is literally the only PDF I know of online about the unit, and it is uselesshttps://componentfun.com/media/resources/PevonoPS305manual.pdfThere are a few caps across the output. I don't see any reverse polarity protection or anything else. It seems to rely on the STP75NF75 body zener for protection and that is not cutting it.
PFAFF 1475 CD sewing machine - motor problem - Page 1
Forum section: electronics / repair

author: MrWifiHifi
author_rank: Regular Contributor
timestamp: June 24, 2024, 09:52:12 am
content: HelloThis sewing machine came to me for repair. It has exactly this problem.When I step on the pedal, the motor starts up nicely, but as I press more on the pedal, just before the end, the motor starts to full speed and stops. I have the machine disassembled at the moment, on the main board I found transistors that provide control pulses. After measuring with an oscilloscope, I came to the conclusion that the microcontroller turns off these control pulses for the motor. So I don't know if some sensor is to blame or if the microcontroller is faulty. I don't have a schematic of the main board for this machine.Has anyone encountered a similar problem, or how to proceed further? Or does anyone have schematic for that main board?

author: Qw3rtzuiop
author_rank: Frequent Contributor
timestamp: June 24, 2024, 11:19:33 am
content: I had some troubles with that machine too. But i dont know if the fault was identical. However you can measure the resistance of the pedal at the connector. Its just a variable resistor. I my case the conductive layer was depleted. There are spare parts available:https://www.naehzentrum-braunschweig.de/Zubehoer-nach-Modell/Pfaff/Pfaff-1473/Pfaff-Widerstandsbahn-Anlasser::17605.htmlhttps://www.naehzentrum-braunschweig.de/Zubehoer-nach-Modell/Pfaff/Pfaff-1473/Kontaktfeder-Anlasser-Pfaff-ATK-0001-ATK-0033-ATK-0080-ATK-0070::17635.html

author: MrWifiHifi
author_rank: Regular Contributor
timestamp: June 24, 2024, 11:59:22 am
content: I measured pedals resistance and it is OK, also measured voltage on pedal when machine is powered up. I suspect there is something wrong in analog part of circuit (there is 1x LM358 and 2x LM339), or worse, the 8051 on board is loosing bits in program memory. Or it might be some dirty sensor or something.

author: Qw3rtzuiop
author_rank: Frequent Contributor
timestamp: June 24, 2024, 02:08:23 pm
content: But did you measure over the whole range of the pedal? If the machine receives one short full speed impulse it does one stitch at that high speed.

author: MrWifiHifi
author_rank: Regular Contributor
timestamp: June 24, 2024, 04:12:16 pm
content: Yes, I measured it over the whole range of pedal. When pedal is not pressed, the output is open. If I start to push on a pedal, the wiper comes on resistive track. From minimum (around <1kohm) to maximum (around 20kohm). When pedal is fully pressed, the output is shorted.I measured pedal and also voltage on the pedal when machine was turned on. On pedal there is some kind of ramp signal which is changing amplitude with pedal position. When motor turns of, there is still signal on pedal.As I said earlier, I measured ot with scope, the microprocessor which is generating pulses for triacs is turning off those pulses, but I don't know why.
Phase Perfect dpc-a10 Hall effect sensor ID - Page 1
Forum section: electronics / repair

author: Hardplates
author_rank: Newbie
timestamp: August 17, 2019, 04:04:30 pm
content: Hi,I am new to the forum. I am trying to repair a digital phase converter for myself. It has to current sensors that monitor L1 and L3(the manufactured leg) I believe inside them is a hall effect sensor that has the marking 16L which I cant find anything about. I believe when the previous owner was changing the AC capacitors they bumped this sensor and broke the 5 volt and signal pins off it internally. With the L1 one removed the LEDS don't even come on when I power the board up on the bench so it would makes sense that it wont try to generate the 3rd leg if it doesn't see the L3 sensor there. There are no factory markings on the sensors other than a white dot and 125 hand written on the top (I assume they were a hand matched pair?) I do have the L1 one that is functional. Does anyone know how to figure out what I need to replace the broken part?Thanks,Paul

author: fzabkar
author_rank: Super Contributor
timestamp: August 17, 2019, 04:33:22 pm
content: The logo looks like Allegro.You might start looking here:http://pdf.datasheetz.com/data/Integrated%20Circuits%20(ICs)/Power%20Management%20-%20Specialized/A8424EESTR-T-datasheetz.pdfAFAICT, the part marking usually (?) corresponds to the last 3 digits of the part number.

author: Hardplates
author_rank: Newbie
timestamp: August 17, 2019, 05:28:10 pm
content: The only one on the list that ends in 16 seems to be a 4 pin but thank you. The good current sensor seems to put out 4.6 volts regardless of if I have a live current drawing load ran through it or not.....maybe I'm testing something wrong.

author: Hardplates
author_rank: Newbie
timestamp: August 17, 2019, 09:28:54 pm
content: It appears to be an overload protection circuit that shuts down over 125 amps. A simple resistor works as a jumper while I'm searching for the main problem. If anyone knows anything about the blue phase perfect converters I would love to learn about them. The manufacturer chooses to no longer support them and no one else makes anything like it.

author: fzabkar
author_rank: Super Contributor
timestamp: August 18, 2019, 01:05:07 am
content: Could the sensor be an A3516L (A3516LUA)?https://www.allegromicro.com/~/Media/Files/Datasheets/A3515-6-Datasheet.ashxIt might help to know the date codes of other chips in your device. Then you could search for likely candidates at the Wayback Machine.http://web.archive.org/web/*/allegromicro.com

author: Hardplates
author_rank: Newbie
timestamp: August 18, 2019, 01:14:18 pm
content: That appears to be the one! Thank you much.
Phenolic Case Repair (Simpson260) - Page 1
Forum section: electronics / repair

author: SG-1
author_rank: Regular Contributor
timestamp: June 28, 2022, 07:28:00 pm
content: Hello friends, I am restoring an old Simpson 260 series 8M. Am looking for guidance on repairing the phenolic case. It is cracked & broken at one handle attachment point. Does anyone have any suggestions on an adhesive to reassemble the pieces? Will probably use fiberglass screen & epoxy inside to increase strength, just have to carefully watch clearances.

author: Gyro
author_rank: Super Contributor
timestamp: June 28, 2022, 07:47:00 pm
content: I would use epoxy for the general gluing too.

author: BrokenYugo
author_rank: Super Contributor
timestamp: June 29, 2022, 07:09:55 pm
content: Epoxy (high strength slow cure) and good prep work, everything rough and degreased.

author: Oilngas
author_rank: Contributor
timestamp: June 30, 2022, 01:55:07 am
content: Not sure if this is what you need, but a new case back is only $19.86 here...https://www.metersales.com/shop/product/03-320525r-31903?category=138&search=simpson#attr=43436,164312,151029
Philips 3226 Oscilloscope VDR repair - Page 1
Forum section: electronics / repair

author: jpwolfe31
author_rank: Contributor
timestamp: September 27, 2021, 08:39:20 pm
content: I just finished a minor repair to a Philips PM3226. I purchased this used about 25 years ago.However, it is not clear exactly how this repair worked and am looking for some advice.Only 1/2 of the x axis on the scope was working. I traced the problem down to a VDR in the x final amplifier. This VDR and several others used in the scope were not specified beyond the word “VDR”. All are brown with a black band, red top and a white dot on one side.My preference would have been to replace the VDR with a new one. However, I was not able to locate the same part.I found this thread that addressed the VDR issue and it stated this VDR had the following specs: asymmetric VDR with a reference of 1.35V at 1mA - Red top = 1.35V @1mA, Black = 10%, White spot is the cathode. (http://www.tv-forums.com/forum/TV_Equipment_C4/TV_Repair_Forum_F3/VDR_Philips_4822_116_20063_P144808/)The last poster in the thread stated he fixed a bad VDR in the y output amplifier of the same scope by leaving the VDR in place and adding two signal diodes in series across the VDR leads to keep the voltage across the VDR to less than 1.5 volts.I tried this and it worked for my issue as well. The scope appears to be working fine now! See attached pdf showing the x final amplifier and the diode additions. I also attached the amplifier description and the full schematic from the manual if this might be of interest.Two questions.1. I would have preferred to replace the bad VDR with one that had the same specs. Is it possible to find a replacement with just the info above? In my searches, I did not see any VDRs specified this way.2. What is the VDR intended to do in this circuit and how have I compromised the circuit’s function by adding the diodes?Appreciate any insights. Thanks!

author: jpwolfe31
author_rank: Contributor
timestamp: September 29, 2021, 04:49:56 pm
content: I was able to find this Philips color code chart for caps, VDRs and resistors. The part at issue is the 1.35 volt asymmetric VDR varistor in the lower left.
Philips 3230 dual beam oscilloscope vertical position  - Page 1
Forum section: electronics / repair

author: MrElectric
author_rank: Contributor
timestamp: February 14, 2020, 06:24:56 pm
content: I bought a used Philips 3230 dual beam oscilloscope. All seems to work ok. However, it seems like the vertical position of the traces gets lower every time I start it. First, it was possible to move both traces both up and down, out of sight. But now I can only see one of them, and it's so low down that I can not move it to the center any more, only down, out of sight. I'll try letting it cool down for a few hours to see if that makes any difference. I wonder if some (or all) of the capacitors should be replaced.There is a high pitched noise when turning the unit on. Not sure if it's the vacuum tubes heating up, or if there is a bad capacitor somewhere. I have heard similar noises from other electronic equipment where the sound was caused by bad capacitors.I think I'll start by replacing the electrolytic capacitors in the Y-amplifier. I'll remove a couple of them first, to do a leakage test. If they are leaky (which I suppose they are), I'll replace all of them. All of these capacitors are axial, mounted standing, with one leg bent over. I'll check the hole spacing to see if might be neater to replace them with radial electrolytic capacitors instead.
Philips 32pfs4132/12 LCD TV repair - Page 1
Forum section: electronics / repair

author: shybear
author_rank: Newbie
timestamp: January 26, 2021, 07:33:39 pm
content: hi,this TV comes with power ON red LED blinking.Power board model is 715G7734-P03-005-002H and schematics (also in Service manual!) is different but not su much.So for reference I worked on 715G7734-P01-005-002H and I find Q9101 defected even if it was no burnt.Then I checked all others components around it also on SMD side and changed as well IC U9101.-See reference picture for all tested (OK) and changed (CH) components.All seems to be fine but TV still doesn't power on and power ON led still blinks.So I tested voltages on exit connector CN9101 and instead of 12V as written I've:around 8V without cable on the other board connected that goes down to around 4V if I attach the cable.There is an other strange thing no matter if power board is connected or no, main capacitor C9801 doesn't discharge and stay at 300V.I think that primary side is ok then now I'll try to looking some problem on secondary side, any help will be reapply appreciated.

author: fzabkar
author_rank: Super Contributor
timestamp: January 27, 2021, 04:28:55 am
content: What is the VCC voltage for IC9101?

author: shybear
author_rank: Newbie
timestamp: January 27, 2021, 12:49:35 pm
content: Quote from: fzabkar on January 27, 2021, 04:28:55 am...moving on repair search I wanted to desolder mosfet Q8601 / AOD2922 but even if I didn't force it so much one pin a part of plastic broken so I can't say if it was bad or good. Anyway I tested all SMS resistors around it and D8601 is ok.Replying to you, I powered the board without broken mosfet (I've to buy it) and on CN9101 voltages are just mV but Vcc on pin 5 of U9101- PF9005AG (that is the 3+3 pin not 4+4 as the posted picture) is 12V so I suppose its right!I also checked all SMD resistors that exit from IC to point (A) that go to diode bridge.On C9801 there are 300V that doesn't discharge for itself when power is moved off.

author: fzabkar
author_rank: Super Contributor
timestamp: January 27, 2021, 09:29:47 pm
content: When the supply is regulating, I expect that the Vcc pin (pin #6) should get around 16V or so from the auxiliary secondary winding of the transformer.Unfortunately the only information I could find on the PF6005AS IC is this brief datasheet:http://www.powerforest.com/upload/userfiles/1443694534890020877.pdf

author: shybear
author_rank: Newbie
timestamp: January 27, 2021, 10:30:58 pm
content: Quote from: fzabkar on January 27, 2021, 09:29:47 pm
Philips 40HFL5010L/12 TV repaired - Page 1
Forum section: electronics / repair

author: samnmax
author_rank: Regular Contributor
timestamp: September 09, 2021, 09:34:07 am
content: Hello,Yesterday I found this 40" TV on the street, it was clear that someone thought it could be repaired, as it was nicely placed, prominently, on an edge besides the rubbish bins.I quickly found the issue: shorted SMD diode on secondary side. Sorry, no solder side picture, but it was under the red circle in the attached image.It was a SK510C, replaced with a THT SR510. I drilled a hole to pass a leg through and soldered the other leg to some bridges.It's a hotel TV from 2017 with some commercial features that are useless at home, and the SmartTV is atrocious and obsolete. However, a 40" FullHD TV for free is not badCheers
philips 43pus7908/12 doesnt turn on  - Page 1
Forum section: electronics / repair

author: loordgek
author_rank: Contributor
timestamp: August 01, 2024, 02:09:48 pm
content: i have 12v 5v 3.3v 1.8v and 1voltthe standby led does not turn onthe tcon board does not get power, it is held back by a mosfethttps://alltransistors.com/mosfet/transistor.php?transistor=20438at gate and source i have 12 volt but i dont know if if it is a NO or NC mosfetif somebody has a schematic available

author: m k
author_rank: Super Contributor
timestamp: August 09, 2024, 07:01:15 pm
content: How is drain?Take it out and short the holes.
PHILIPS 55PFL7008K/12 - Page 1
Forum section: electronics / repair

author: aqarwaen
author_rank: Regular Contributor
timestamp: December 28, 2019, 07:30:58 pm
content: does anybody know where i can get replacement board for 55PFL7008K/12i am suspecting that any board may dead,since i only black get screen and can hear sound...tried very single remote key,only one working is power key...also then i connected xbox one hdmi cable with hdmi port what tv currently has connected it started black screen started flickering brightly,it did not happen with old cable,then i connected it with backdoes anybody else think it board issue? or maybe it is just software issue??http://www.p4c.philips.com/cgi-bin/dcbint/cpindex.pl?ctn=47PFL7008K/12&dct=PSS&scy=GB

author: kosomsk
author_rank: Regular Contributor
timestamp: December 29, 2019, 08:27:05 am
content: Hi! Search "QFU1.2 issues" ) But there is bad answers
Philips 60PFL6008H/12 - Front Red LED blinking 2 times - Page 1
Forum section: electronics / repair

author: tchoy668
author_rank: Newbie
timestamp: December 25, 2022, 03:56:19 pm
content: The Philips 60PFL6008H/12Hello,I am trying to repair this Philips Smart TV (model 60PFL6008H/12). The red led blinks twice. With the power supply connected to the mainboard, I measured the +3.3V and +12V on the output connector of the PS board. When the power supply is disconnected from the mainboard, the +3.3V is present while the +12V is absent. I suppose it is normal since no standby signal was applied.However, in the "hot" side of the PS board, I noticed the black, discolored diode D601. This diode is marked as "MUR460". When unsoldered and tested with a multimeter, the diode reads open 487ohms in both directions, not sure is the diode ok or not. when the diode is connected in the circuit and powered up, there is 430V on one end and floating voltage at the other end when the AC power just connected.at this time +3.5V and +12V are measureed at IM90 pins, and +28V on the other Display board.When pressed on the power on button, and the front LED light starts blinking 2 times in sequence, the +12V at IM90 connector is goes to 0V, and 28V also drop to 1V. at this time both side to the D601 didoe the votage is the same 428V respect to ground. the Recover circuit seem like not functioning.May i know is this diode defected? or other components giving problem.Thank you!

author: modoran
author_rank: Regular Contributor
timestamp: December 25, 2022, 06:23:51 pm
content: If that reading of 487 is in both ways then the diode is faulty. It remains to be seen if thats the only fault or not.

author: tchoy668
author_rank: Newbie
timestamp: December 26, 2022, 03:18:24 am
content: Thanks. Getting the new MUR460 diode to replace, see any other issue.

author: tchoy668
author_rank: Newbie
timestamp: December 27, 2022, 07:39:14 am
content: I have replaced the MUR406 diode, the red led light no more blinking but the whole screen no display.The standby +3.3V still there, when power up, the led blink once then off.how to dianose from here? any suggestion?Thank you!

author: tchoy668
author_rank: Newbie
timestamp: January 09, 2023, 09:24:24 am
content: When the AC power applied. All the votages are present:3.5V, 5V, 12v. 24V all at the plug pins and can be measured.At this time LED is off.a minutes later or press the remote power on button, the front LED starts blink twice again and all voltages go to off, accept the 3.5V remainspls advise what are the possible cause?Thank you
Philips 6700 series TV - Page 1
Forum section: electronics / repair

author: justaguy
author_rank: Contributor
timestamp: June 24, 2024, 07:01:39 am
content: Dear forumers,I have a Philips TV series 6700 (pn 43PUS703/12) which is giving problems. From time to time (like once per week) is showing symptoms like: slow to respond to the remote, takes ages to switch channel, loses connection to the wifi a/o the philips hue bridge, shuts down completely, apps (like prime video) freezing. Removing the power for a minute solves the issue.To me sounds like a sw problem, like fw or cache corruption, but may have hw roots like a flash or capacitors aging. I am waiting for the symptoms to become worse and more frequent before opening it up, but in the meantime I´m asking you for some advice.Is it maybe a known defect? Is there a service menu that allows me to perform some kind of self-test? Or a deep reset procedure?Thanks!
Philips SBC 550 frequency counter schematic wanted ?? - Page 1
Forum section: electronics / repair

author: oz2cpu
author_rank: Frequent Contributor
timestamp: November 23, 2022, 09:26:30 pm
content: problem with prescaler, set or reset stuff, so i really need a schematic,anyone ??

author: MikeK
author_rank: Super Contributor
timestamp: November 23, 2022, 11:54:11 pm
content: If you don't get a response, you might check the source links in this video: