hybridfree/eevblog-posts huggingface dataset:
Integrated Amplifier - Page 1
Forum section: electronics / repair

author: yalect
author_rank: Regular Contributor
timestamp: April 19, 2020, 04:24:32 pm
content: Hi,I would like to ask you that I have an oldSansuiintegrated amplifier, I am looking for its daigram to fix problem happened in.may I can find some PDFs or websites that provide me daigrams?Thank you

author: feedback.loop
author_rank: Frequent Contributor
timestamp: April 19, 2020, 04:36:00 pm
content: You did not even mention the model.

author: yalect
author_rank: Regular Contributor
timestamp: April 19, 2020, 04:43:26 pm
content: Thank youSansui A40

author: bob91343
author_rank: Super Contributor
timestamp: April 19, 2020, 05:20:02 pm
content: https://www.hifiengine.com/manual_library/sansui/a-40.shtml
Intel NUC NUC10i5FNH wont talk to DVI-D display - Page 1
Forum section: electronics / repair

author: gbrowne
author_rank: Newbie
timestamp: November 12, 2022, 02:54:26 pm
content: I need to connect a second monitor to my NUC NUC10i5FNH.It's a Samsung Syncmaster 204Ts and it works fine with my old Dell Precision M6400 when I connect the monitor DVI input to the Dell DP port via a DP/HDMI convertor widget (the Dell doesnt have HDMI).When I connect the monitor to the NUC using a DVI-I to HDMI cable nothing is seen. I have tried a DVD-I single link cable and a DVD-I dual link cable, but no show. Any tips or pointers would be great. So far the NUC has been a doddle to set up with Ubuntu 22.04.1 !Cheers, G
interactive ultrasound pen -parts replacement search - Page 1
Forum section: electronics / repair

author: kokodin
author_rank: Regular Contributor
timestamp: February 03, 2023, 08:33:14 am
content: helloI am currently trying to fix what highschool students have broken, ebeam system 3 interactive pen.System works on a basis of emiting ultrasound bursts of noise and measure how loud they are by 2 microphones determining the difference in volume and how long the detected soun is as coordinate system while emiting infrared information which button is pressed.Unfortunetaly students have decided to "take apart" one and only pen we have for ebeam system. We have imitation systems and we had spare parts pens for those , this is how i fixted this one 10 years ago. But this time i run out of spares and parts, and i can't even find anything similar. If anyone have an idea what it can be replaced with i gladly test your idea.Missing/broken part is a ring made out of plastic film covered with some metalisation , working as piezo emiter of some sort.Shape is kind of important because it needs to evenly transmit sound in all directions , otherwise it would only work at far end of the screen and loose all accuracy close to reciever or one of the microphones loosing line of site to the other one. I determined pen itself is electronically ok by replacing broken emiter with inards of arduino ultrasound proximity detector, but the small piezo emiter in shape of a metal disc work only in one direction and can't be installed inline of the pen, because tip piece go trough the center .to make things worse company who made it halted production in 2019 and so did all the competetion, so getting spare parts become even harderif there was some piezo strip i could buty and just wrap it around the emiter post it probably would work but i have nothing.
Interesting Product - Page 1
Forum section: electronics / repair

author: raptor1956
author_rank: Frequent Contributor
timestamp: October 31, 2023, 07:31:02 am
content: I just happened to see a YT Short from a company called "Omnifixo" -- it's a soldering aid like Helping Hands but, well it looks like a great idea. Anyone know about them or have any experience using them?https://www.youtube.com/shorts/3UV0yA0uNZYBrian

author: Swake
author_rank: Frequent Contributor
timestamp: November 01, 2023, 06:34:38 pm
content: Interesting 'wrist' holders. But 4 holders for 55eur is expensive for what it is, especially because there is only one horizontal height possible.

author: RAPo
author_rank: Super Contributor
timestamp: November 01, 2023, 06:46:50 pm
content: I have this tool. Works really great; easy to adjust.I remember pondering over the price, but it has paid back itself.

author: Swake
author_rank: Frequent Contributor
timestamp: November 01, 2023, 07:01:44 pm
content: What are you using it for?

author: RAPo
author_rank: Super Contributor
timestamp: November 01, 2023, 07:08:54 pm
content: Soldering and everything where you need a third hand.The magnets are powerful.Added info: I had a CVA that left my left hand without much power and control. It's a godsend for me.Quote from: Swake on November 01, 2023, 07:01:44 pm

author: PlainName
author_rank: Super Contributor
timestamp: November 01, 2023, 09:27:24 pm
content: Got this as well. Only thing that gets me is that you expect the bottom grip to move when you press the lever, but it's the top one that does (doesn't take too long to gain new muscle memory). Otherwise it is great.Has hidden talents: magnets can make croc clips stick to the uprights so they don't drag down whatever tiny wire they're gripping. The grips can be reversed so they are close to the base rather than sticking out (but you lose most of the flexibility). And apparently you can put power through them to simplify getting volts onto PCBs. Or something.I find the base just the right size, and adjusting the angle and direction of the grips is so much simpler than any other helping-hand-style thing I've tried (and got a few, trying to find The One that works). Price held me off for a while but don't regret getting this, unlike some other kit that looked good but lives only on a shelf.
Interesting SDG2042X Power-Up Problem - Page 1
Forum section: electronics / repair

author: Unknown
author_rank: Unknown
timestamp: August 30, 2019, 06:06:26 am
content: My Siglent SDG2042X waveform generator has an interesting issue. About 1 out of 5 times when I turn it on the fan comes on (so I know the power supply is working), but the screen never turns on, no buttons illuminate, and no relays click - in other words, the machine doesn't boot. After prodding around a bit I found that unplug the power cord, waiting 5 sec, and trying again will get it to happily boot every time.This doesn't make sense to me, especially considering I thought it had a hard power button. Do any of you have any ideas as to what the root cause could be?

author: tautech
author_rank: Super Contributor
timestamp: August 30, 2019, 07:05:07 am
content: Yep, weird.Do you have the latest firmware installed ?23R8
Intermittant Astron RS-35A - Page 1
Forum section: electronics / repair

author: bcr751
author_rank: Newbie
timestamp: February 17, 2024, 10:46:43 pm
content: Occasionally, the output on the above power supply drops from 13.8vdc to zero. It is only being used to power a ham receiver, no transmitter is connected. So far, I have been unable to sneak up mon this problem to find out the cause. I am a bit short on technical knowledge. Could someone please point me in a direction that may help me find the cause of this problem.Doug

author: coromonadalix
author_rank: Super Contributor
timestamp: February 18, 2024, 07:20:30 am
content: Bad solder joint, bad connection on the output jack .... visual check on all parts, transistors, screws ... solder on pcb

author: p.larner
author_rank: Frequent Contributor
timestamp: February 18, 2024, 12:04:52 pm
content: try removing the covers and tap around all the boards and see if you can invoke the fault condition,be carefull of mains voltage tho.
Intermittent Current Switches HP 3466A DMM [FIXED] - Page 1
Forum section: electronics / repair

author: enut11
author_rank: Super Contributor
timestamp: December 21, 2019, 08:43:40 pm
content: I am in the process of restoring an old HP 3466A DMM (1974 manufacture I think).Most of the DC amps switches are intermittent, especially the 2mA one.Measuring the 2mA shunt resistor gives wildly varying results. It should read 100 ohms and only does so if I short the appropriate switch pins (see yellow crocodile clip).The switches seem to be sealed so no easy way to clean them.Can these switches be disassembled without de-soldering from PCB?enut11

author: enut11
author_rank: Super Contributor
timestamp: December 21, 2019, 08:54:16 pm
content: HP3466A main board. Some of the amps push button switches behave intermittently.

author: wn1fju
author_rank: Frequent Contributor
timestamp: December 21, 2019, 09:56:14 pm
content: My 3466A was even worse than yours - none of the switches worked correctly. I surmise they tarnished from sitting around unused for decades.What I did was to drill very small holes at the top/back of each switch. That allowed me to flood it with contact cleaner. No problems at all after that.In my case, the 3466A wasn't a piece that I was too excited about, so the prospect of actually ruining it by drilling holes wasn't upsetting. You mayfeel otherwise in your situation.

author: enut11
author_rank: Super Contributor
timestamp: December 21, 2019, 11:55:03 pm
content: This thread (post #14 and #16) shows how to repair sliding push-button switches after removing them from the PCB.https://www.eevblog.com/forum/testgear/hpagilentkeysight-34401a-2w-problem/However, I am still hopeful of finding a solution that does not involve un-soldering switches or drilling holes in them.enut11

author: enut11
author_rank: Super Contributor
timestamp: December 22, 2019, 12:05:46 am
content: a better view of the recalcitrant switches.

author: enut11
author_rank: Super Contributor
timestamp: December 27, 2019, 10:56:55 pm
content: I eventually removed one of the switches to see if it could be disassembled and cleaned.Sadly no go, no way to get into it without breaking the top cover, so it was back to plan B?

author: enut11
author_rank: Super Contributor
timestamp: December 27, 2019, 11:03:59 pm
content: This involved drilling a small hole at the top back end of the switch and flushing it with contact cleaner.Thanks for the tip @wn1fjuI found that if I pushed each switch fully in while drilling, this minimised any plastic swarf entering the switch.My HP 3466A multimeter now works well on all ranges.Happy ending
Intermittent LeCroy PP002 probe autodetection pins - Page 1
Forum section: electronics / repair

author: pipe
author_rank: Contributor
timestamp: December 07, 2021, 07:43:07 pm
content: I just acquired a LeCroy 9354AL with threeLeCroy PP002probes (couldn't find the fourth). However, all the probes have a dodgy and unstable X1/X10 auto-detect which is annoying in this unit since the manual selection menudisappearsif it believes it knows better.The fault seems to lie in the probes themselves and not in the scope - they are even unstable when I measure the resistance between the pin and ground. Attached is a crappy photo for people who wonder which pin I'm talking about. Apparently I couldn't get the "Inline expandable thumbnail" to work.I could just tape them over (or break them off! But I don't want to do that...) but I would much rather spend some time and effort trying to restore them. However, I can't find a way to get into these things, and before I break them by accident I wanted to check if you guys have any pointers.I'd be interested in photos from dismantled probes, maybe a probe-specific service manual, or information about similar probes. I have of course spent some time searching for this but didn't even find information about the resistances required to identify, or if this some sort of standard.

author: shakalnokturn
author_rank: Super Contributor
timestamp: December 07, 2021, 10:22:05 pm
content: I haven't had the problem with any of my Lecroy probes but don't own any PP002.On the PP006 a 1/10 probe, it's 11.1k between identification pin and shielding.Before pulling it appart I'd try a drop of contact cleaner on the pin and between the BNC lock and outer conductor then spin them a little, including the pin.Make sure not to get any cleaner in the compensation bloc.

author: tautech
author_rank: Super Contributor
timestamp: December 08, 2021, 09:01:32 am
content: Quote from: shakalnokturn on December 07, 2021, 10:22:05 pmThis ^OP, as a sanity check 10k between the sense ring and the BNC GND/outer should sense 10x at the scope. Generally there is some tolerance in the sense pin resistance.Sometimes the sense rings can get tarnished and some rotates of the probe connector can help to polish them up for better/reliable sense pin contact.

author: pipe
author_rank: Contributor
timestamp: December 29, 2021, 06:06:23 pm
content: Quote from: shakalnokturn on December 07, 2021, 10:22:05 pmThanks, I tried this on one probe before I made this post, and it didn't seem to do much good. Now I tried that same probe again after repairing a knob on the front panel of the oscilloscope - and it now works perfectly! I guess it just needed some time to soak in.I now did the same to my other probes and I was far more liberal with the solution this time, almost drenching the pin (and only the pin, careful with the compensation block as you say). It cured all my probes.
"Intermittent Noise" is a bit of an understatement on this one... - Page 1
Forum section: electronics / repair

author: klausman
author_rank: Regular Contributor
timestamp: May 03, 2025, 01:44:47 pm
content: Harman Kardon PM655 Vxi. The small pushbuttons on the front panel are infamous for becoming dodgy (and are of course unobtainium). But my scope says there is a massive DC offset problem as well. Time to dig in!
Intermittent Power within device - Page 1
Forum section: electronics / repair

author: GregB10
author_rank: Newbie
timestamp: August 24, 2023, 07:53:01 pm
content: Mother-in-laws garage door opener works fine until there is a break in power (power outage, or unplug). With power to the unit, it takes a month, or longer before the circuit board LED's light back up, and opener functions again.Have cleaned all connections, and even re-flowed solder joints. Can't see any perceptible capacitor swelling.I'm sure it's something simple. Would rather repair than replace entire PCB. Thanks!

author: Kim Christensen
author_rank: Super Contributor
timestamp: August 24, 2023, 08:05:09 pm
content: Does it have a wired switch in the garage?If so, is this button also affected by the the 1 month delay, or is it just the remote?
Internal wire in a moving head - Page 1
Forum section: electronics / repair

author: Vicus
author_rank: Regular Contributor
timestamp: May 03, 2025, 06:07:39 pm
content: I need to replace some wire in a moving head that broke. I figured out that are probably PTFE or TFE insulated and have very fine strand, more or less from 0,1 to 0,15mmq of total area but with 0,05-0,07mm strand. The wire need to be tough enought so they don't brake with multiple bending and the rubbing action. I can find fine stranded wire, like the Stabuli 60.7170-21 with a TPE insulation but this insulation is way too grabby and the wire don't slip each other. Or I can find TFE cable like the Belden 83043 but the strand is too thick. Any idea of where I can find a suitable wire? Thanks.

author: neillnz
author_rank: Contributor
timestamp: May 04, 2025, 08:09:39 am
content: I used to service Martin equipment here in NZ. Whenever I needed that wire I purchased it as a spare part. I have never come across the same type of wire that was not a spare part. I feel your pain. If the manufacturer of the product you have is not willing/able to provide spares have you considered purchasing a spare part from another model/brand and use the wire? Sorry not very helpful, I hope you find what you need.

author: Vicus
author_rank: Regular Contributor
timestamp: May 04, 2025, 05:03:21 pm
content: Manufacturer have a spare parts catalog but there is no wiring. Also there is an upgrade in which the motor driver board is moved from the base to the arm so le wire that is subject to torsion stress. I did buy the board but I have to made some new wire. The support replay me to send the macchine back and they will do the job. Unfortunatly this is my job I don't want to pay some one else to do it.If I can't find I'll try with the TPE insulated wire wich I read that is exellent for abrasion resistance.
International Rectifier IR 5905 What is it? - Page 1
Forum section: electronics / repair

author: tru3533
author_rank: Regular Contributor
timestamp: December 14, 2018, 06:53:49 pm
content: Hello,Trying to identify this component: International Rectifier IR 5905Located in an Engine Control UnitWhat is it? Ay idea?

author: JKKDev
author_rank: Regular Contributor
timestamp: December 14, 2018, 07:29:25 pm
content: I'd guess it can't be too far fromthisone. Look for IRF 5905 if you want to try to find the exact thing but I can't find it.

author: tru3533
author_rank: Regular Contributor
timestamp: December 14, 2018, 09:17:04 pm
content: IRF4905 is a P-Channel and 5905 can be a N-Channel? so difficult to conclude what it is

author: JoonasM
author_rank: Newbie
timestamp: March 18, 2021, 02:04:09 pm
content: Up!Having probably same control unit and this IR 5905 is burnt down. I cant find any data about it except it can be IRFC5905 which is of course obsolete and informational part on Infineon site is: 55V Size 230x170 Gen 5 HEXFET CHIP PACK, Package Equivalent IRF5705.This IRF5705 is also mysterious as I can't find any info on that one also.Any suggestions?Thanks!

author: JoonasM
author_rank: Newbie
timestamp: March 18, 2021, 03:24:19 pm
content: Hi again! I did farnell search with what I know and woopydoo there is only one option at Infineon products range:https://uk.farnell.com/infineon/irf3805strl-7pp/mosfet-n-ch-55v-240a-to-263/dp/2839478?st=irf3805strl-7ppAint it nice? Only package available is correct TO-263 aka D2PAK with relatively low resistance and heavy duty 240 A of current lifting which sure does this heavy lifting excavator doAnd most importanly isn't this coincidence in the end there 5905 -> 3805Well I hope I'm right! I hope to post it here how did it go.

author: lukipl
author_rank: Newbie
timestamp: October 27, 2022, 09:44:21 am
content: Hello tru3533,Did you solve the problem? What MOSFET did you use?Or maybe someone has photos of this plate from the bottom. I have a damaged measuring resistor. It is in the middle of the plate near the transformer

author: fzabkar
author_rank: Super Contributor
timestamp: October 27, 2022, 05:34:07 pm
content: Check out the 1994 product catalogue (page 65 onwards):https://mirrorservice.org/sites/www.bitsavers.org/components/internationalRectifier/"SMD-220" is a similar looking package style, but I don't know its dimensions.Could "519C" be the part number rather than "5905"? (probably not -- other IR devices have the part number on the top line)The part numbers in the catalogue would suggest that "5xx" corresponds to a 100V device. The "C" appears to indicate "low charge". A "9" prefix indicates P-channel.
Intron DSO 2020A Service Manual Required - Page 1
Forum section: electronics / repair

author: IntronDSOs
author_rank: Newbie
timestamp: August 05, 2021, 11:12:19 am
content: I need Service Manual or Schematic Diagram of Intron DSO 2020A . Kindly send it to me if somebody have it, will be much appreciated.Thanks and Best Regards
Intron Instruments DSO-2000A Oscilloscope both channels tilted - Page 1
Forum section: electronics / repair

author: jakekoo
author_rank: Newbie
timestamp: January 30, 2020, 05:38:38 pm
content: I got this oscilloscope in really good condition and about everything seems to work except both of the channels are tilted by the same degree. I find just about nothing about this Intron Instruments by googling. All the trimpots are marked only by some number and letter combinations. How should I proceed?Oh, first post here. I'm electrician and know the hazards here.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: January 31, 2020, 04:47:03 am
content: Most likely the yoke has turned on the rear of the CRT.Im no expert on CRT but have tinkered with them a little over the years, this is what it seems like to me.

author: m3vuv
author_rank: Super Contributor
timestamp: January 31, 2020, 07:42:47 am
content: has the crt come loose and rotated?

author: jakekoo
author_rank: Newbie
timestamp: January 31, 2020, 09:05:48 am
content: There was trace rotation potentiometer on the back panel which solved the problem.This potentiometer is rare on oscilloscopes from this era but this being kind of digital makes it possible.

author: tggzzz
author_rank: Super Contributor
timestamp: January 31, 2020, 01:34:04 pm
content: Quote from: jakekoo on January 31, 2020, 09:05:48 amNo, and no. They were common and are nothing to do with it being digitising.

author: shakalnokturn
author_rank: Super Contributor
timestamp: February 02, 2020, 01:28:51 am
content: There is no "yoke" on this type of CRT.At least in the era ofroundCRT's you could do a physical trace-rotate
Inverter Control Board Troubleshooting - Page 1
Forum section: electronics / repair

author: lost_sock
author_rank: Newbie
timestamp: June 28, 2023, 10:11:58 am
content: Hoping someone might be familiar with these inverter control boards. The same board looks to have been used by many of the inverter manufacturers, must, power jack, powerstar, aims, cosuper, devel. But I can't find a schematic for it anywhere!The unit I have is a cosuper LPT5000-224. 5000W 24V low frequency, 230V input. The problem is with AC input voltage measurement, it pretty consistently measures around 5v higher than the actual input but still functions fine, every now and then the reading drifts way off though, like +30V and the inverter will throw a fit beeping and switching to battery thinking the AC input is out of spec.Maybe of interest, the MCU is a MC908MR32CFUE.A visual inspection doesn't show any bulging caps or heat discoloration. I tested the long strings of same value resistors as I've read these are the voltage dividers but all seemed to be fine. I had a look under a microscope for cracked joints and didn't spot anything, but I may very well have missed something because I wasn't focused in any particular area.Does anyone possibly have a schematic for these boards? Or possibly some pointers of which components I should be looking at for the AC input voltage detection?Pics:https://imgur.com/a/64HEtqk

author: fzabkar
author_rank: Super Contributor
timestamp: June 29, 2023, 01:22:30 am
content: ISTM that the strings of resistors should be the obvious points of reference. I would follow the outputs of the dividers and see where they go.Just FYI ...https://magnizon.com/uploads/certificates/49/APS%20Series%2012V%20DC%20report1.pdfhttps://magnizon.com/uploads/certificates/49/APS%20Series%2012V%20DC%20report2.pdf
Inverter Fans running continuously 1000 watt device. - Page 1
Forum section: electronics / repair

author: tytower
author_rank: Contributor
timestamp: October 09, 2019, 07:44:27 am
content: I have a new inverter 24Volt to 240 Volt.It was quiet during operations for a few weeks but now the fans come on and stay on whenever the unit is switched on.Looking inside I see a 2 wire device attached to the heatsink but one only.I have had it apart but did not take a pic of the insides .I have one of the outside though .Anyone with experience on this model or perhaps on generic brands on ebay who might help me work through some tests to find out how its controlled?Is it likely to be microprocessor controlled nowadays or would the old transistors voltage change be used ?

author: amyk
author_rank: Super Contributor
timestamp: October 09, 2019, 11:33:53 am
content: Quote from: tytower on October 09, 2019, 07:44:27 amThat's not very useful. More detailed pictures would help greatly.You'll have to do some reverse-engineering of the circuit to figure out.

author: tytower
author_rank: Contributor
timestamp: October 10, 2019, 08:29:26 am
content: Got a few more . closeup is where the sensor attached to heatsink comes from board. Board says RT1 and there is 104 marked so 100K thermistor I assume?

author: tytower
author_rank: Contributor
timestamp: October 22, 2019, 10:04:12 pm
content: So not a lot of response?
Inverter repair on L6599AD - heating transformer - Page 1
Forum section: electronics / repair

author: Brilliant_Tankers
author_rank: Newbie
timestamp: April 05, 2024, 07:08:06 pm
content: Hello friends,I need help in repairing a plate from a bakery oven, model PE1725D0-V1.The plate was damaged as a result of flooding. I have replaced the components marked in red. Instead of L6599AD, I used L6599D and diodes other than the indicated markings.The result is that the inverter started and I have 12V at the output(probably the correct value). However, the main transformer reaches a very high temperature. After a few minutes it is over 80 degrees. Could I have made a mistake, wrong selection of components or have something else damaged? or is it due to the design of this inverter? I attach the documentation of the driver and ask for hints.https://www.st.com/resource/en/datasheet/l6599.pdf

author: m k
author_rank: Super Contributor
timestamp: April 10, 2024, 07:53:49 pm
content: Can you see the type of the transformer?Many transformers are designed to be hot, over 100C is not yet abnormal.

author: Brilliant_Tankers
author_rank: Newbie
timestamp: April 11, 2024, 05:26:36 pm
content: Hello,thank you for your interest.The transformer is marked ICES-EBM CN017325(probably)It seems to me that it heats up too fast and too much. The resistance, measured on the secondary side on the capacitor is about 1k, so it doesn't seem to be overloaded. I am attaching a photo from a thermal imaging camera.

author: m k
author_rank: Super Contributor
timestamp: April 13, 2024, 09:01:57 am
content: Seems that the net is not exactly full of datasheets of these transformers.You can start checking how secondary side reacts when load increases.All energy goes trough that transformer, so it can be as it should.TL431 is referencing how PS2561 is driving the switcher.Transformer's secondary side before diode pair should have a clear effect when load changes.Output voltage should also be that 12V and not follow the load.
MagnaSine MS2012 Inverter Repair Rectifier Identification  - Page 1
Forum section: electronics / repair

author: gr8lakehome
author_rank: Newbie
timestamp: May 29, 2024, 10:55:20 pm
content: Hello everyone, Bought a defective Magnasine Inverter MS2012 to repair. 12VDC to 120VAC , Low AC ouput under load 27VAC , dual fans dead, replaced operate ok, No Fault Codes at all on ME-MR remote.Pulled FET board for component troubleshooting. ALL 20 FETs , no short but on the underside 3 physically blown and shorted rectifiers .I'm guessing they are of the MR750 Family but unsure which specific one , MR750 ,MR751, MR752. No markings what so ever , even under magnification. I'm hoping someone may know so am reaching out .
Inverter Transformer 2200 Series Oscilloscopes, primary resistance - Page 1
Forum section: electronics / repair

author: THM60
author_rank: Contributor
timestamp: December 08, 2022, 01:46:39 pm
content: Hi,I suspect the primary winding of the Inverter Transformer in my Tek 2230 is shorted. When measuring its resistance between terminals 1 & 2 with my DVM, I find 0,7R. What do you think ?Part number is120-1439-01(photo attached). In the worst situation, is this transformer on the unobtainable parts list ?Thanks !

author: TheMG
author_rank: Frequent Contributor
timestamp: December 08, 2022, 02:16:31 pm
content: Not impossible but rather unlikely.A low DC resistance is normal for such transformers. Since they operate at high frequencies the number of turns is small when compared to a 50/60Hz transformer, so the DC resistance being less than 1 ohm is actually not unexpected.

author: WattsThat
author_rank: Frequent Contributor
timestamp: December 08, 2022, 02:36:49 pm
content: <1 ohm is expected, not shorted. Do waveforms 42/43/44/45 match what is shown in the service manual?

author: THM60
author_rank: Contributor
timestamp: December 08, 2022, 03:38:49 pm
content: Thanks for responses.Quote from: WattsThat on December 08, 2022, 02:36:49 pmI can't check that for the time being as the fuse keeps blowing. Two of the three neon bulbs flash (DS858,DS870) and fan shudders one or two times but scope doesn't turn on.

author: jonpaul
author_rank: Super Contributor
timestamp: December 08, 2022, 07:58:56 pm
content: get service manual follow PSU tests and troubleshooting flow chartj

author: floobydust
author_rank: Super Contributor
timestamp: December 08, 2022, 09:51:45 pm
content: From my notes, Pre-regulator transformer T906 (120-1439-01) readings:T906 1,2 3.50mH 2.05 ohms Primary WindingT906 4,5 3.75mH 1.57 ohms Reset WindingT906 9,10 4.50uH 0.22 ohms Tank WindingT906 6,7 452uH 2.00 ohms Aux Windinganother person's measurements:https://www.eevblog.com/forum/repair/tektronix-2213a-scope-exploding-power-supplies!/msg864495/#msg864495I say don't run the scope if DS870 (CRT cathode-grid protection neon) is lit steady. You can see polarity by which pole (-) is lit.I'd suspect the -2kV rail, it might have a heavy load (cooked focus divider resistors) or that output on the HV multiplier (rectifier) has failed where it outputs AC.

author: THM60
author_rank: Contributor
timestamp: December 09, 2022, 01:00:17 pm
content: Thank you so much, I'm going to investigate further with the figures you indicated in hand

author: marcumr
author_rank: Contributor
timestamp: December 09, 2022, 01:53:25 pm
content: Hello.Check out that yellow tantalum, mine had a hole in the bottom and shorted out

author: THM60
author_rank: Contributor
timestamp: December 09, 2022, 02:29:59 pm
content: Hi again Floodybust,I've removed T906 from the main board (pain in the back) for measurements. Inductance and resistance as follow.
Inverter with shorted output cap - Page 1
Forum section: electronics / repair

author: St3venAU
author_rank: Newbie
timestamp: September 16, 2019, 04:06:30 pm
content: I have a 12VDC to 240VAC inverter that has a failed (shorted) output cap. It’s a 0.01uF cap rated for 400VDC. I was wondering if since this cap is across the AC output of the inverter, wouldn’t it make sense to use an AC rated cap instead of DC?Do you guys think that this (https://www.altronics.com.au/p/r3102a-0.01uf-x2-pcb-mains-suppression-capacitor/) would be a suitable replacement, or should I stick with a 400VDC rated cap?Original Cap:

author: james_s
author_rank: Super Contributor
timestamp: September 16, 2019, 04:23:12 pm
content: Typically film caps are good for ac or dc, typically the dc rating will be higher. I'd use one soecifically rated for ac though, cheap capacitor may be why it failed.
Invertor 48V /220V - Page 1
Forum section: electronics / repair

author: Jane
author_rank: Frequent Contributor
timestamp: July 12, 2024, 08:16:07 pm
content: The invertor has 2 air fans that start only when quite a high electricity consumption is needed . Otherwise the fans are quiet. It worked that way for about 2 years. Now,however, the fans work all the time.On the enclosed pictures you can see a region where fans are connected. It seems quite simple. Anyone knows the principle , how the fans are controlled?Thank you

author: Kwakerman
author_rank: Regular Contributor
timestamp: July 13, 2024, 10:00:36 am
content: Looks like you have a temperature sensor attached to the heatsink (first picture top heatsink). Might be for overtenp protection or fan control (or both). Suggest you try and find a circuit drag for it.

author: Jane
author_rank: Frequent Contributor
timestamp: July 13, 2024, 02:44:46 pm
content: Thank you for the reply.Can you please mark in the picture where do you think there is the sensor?

author: voltsandjolts
author_rank: Unknown
timestamp: July 13, 2024, 03:49:09 pm
content: It's here:

author: johansen
author_rank: Super Contributor
timestamp: July 13, 2024, 06:29:51 pm
content: the traces on the board run all the way to it.looks like the fans get power from a rectifier and aux turns on the transformer.

author: Vovk_Z
author_rank: Super Contributor
timestamp: July 15, 2024, 10:20:44 pm
content: Yes, fans get power from a main transformer. The higher load the higher FAN voltage. But there possibly is BJT transistor which controls swit hing on and off of a FAN. And possibly it became shorted.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 16, 2024, 08:09:49 am
content: yep i would have said the same thing, come from the main ac voltage then rectified as DC, a crude way to make them work ... and they are 2 wires only ...the thermal sensor should be used in the main controller section

author: BrokenYugo
author_rank: Super Contributor
timestamp: July 16, 2024, 02:11:48 pm
content: From the pics I would guess transistor Q33 is either shorted or whatever can turn it on is.

author: Jane
author_rank: Frequent Contributor
timestamp: October 03, 2024, 11:58:53 am
content: Finally I checked Q33 and Q31 transistors and they are good. I measured the temperature sensor, which is NTC termistor. It has only about 5kOhm. Is it not small value and because of that it is the culprit why heatsink turns all the time?
Ionic Breeze - Page 1
Forum section: electronics / repair

author: JustMeHere
author_rank: Frequent Contributor
timestamp: March 29, 2020, 05:27:34 am
content: I have an old Ionic Breeze in which both wires broke (no clue how). Does anyone know what type of wire can be used to repair?

author: james_s
author_rank: Super Contributor
timestamp: March 29, 2020, 05:51:53 am
content: From what I could find, it's .009" wire, I suspect it's stainless as some people said they tried guitar string and that failed quickly.
Ipad 1 wifi logic board short - Page 1
Forum section: electronics / repair

author: some guy on internet
author_rank: Newbie
timestamp: May 03, 2025, 11:49:23 pm
content: I have this iPad one logic board that has a short but i don't know how to fix it, i accidentay screwed in a screw where a shouldn't have and then the motherboard got damaged

author: Haenk
author_rank: Super Contributor
timestamp: May 04, 2025, 05:28:10 am
content: Please note that these are multilayer PCBs - so the damage you see on the top layer is likely not the only damage. The top layer might be fixable with enough skill and good tools, the lower layers are extremely hard to fix, getting that fixed is going to be expensive (if possible at all); only few people would even dare an attempt.The bent PCB maybe is easier to fix, maybe not. It requires an experienced tech to take a look at it.Fixing these issues usually means "replace those parts". Which might even be more expensive than just buying a new (used) iPad. A repair on PCB level would cost hundreds of USD, maybe even into a four-digit amout.
ipad 2 activation lock - Page 1
Forum section: electronics / repair

author: m3vuv
author_rank: Super Contributor
timestamp: August 26, 2021, 11:30:06 am
content: I have a friends ipad 2 A1395 thats locked,he has had it for a few years and was using it,he said one day it went wierd on him and locked him out,he has tried all his passwords he can remember but no go,if connect it to my pc and can see the pics he has on it,sort of confims he was using it to take pics at least,is there any way to sort this,ive watched a pile of youtube vids on this and downloaded a few softwares to unlock it but just says device not supported although its supposed to support this model,any idear what i can do,he is a good friend tho and i want to help him out.

author: Simon
author_rank: Unknown
timestamp: August 26, 2021, 12:07:28 pm
content: contact apple? They kind of pride themselves on security and any decent security these days cannot be broken with some dodgy software you may find online. If you do find some chances are it will lock your computer and demand a ransom

author: amyk
author_rank: Super Contributor
timestamp: August 26, 2021, 01:42:35 pm
content: Quote from: Simon on August 26, 2021, 12:07:28 pmThe Chinese repair industry would like to have a word with you...I'm not sure if this exact case is possible but I recommend looking into the darker parts of the Internet.
Ipad 6th Gen A1893 Component Identification/Sourcing - Page 1
Forum section: electronics / repair

author: pdjames14
author_rank: Newbie
timestamp: December 13, 2021, 06:04:58 am
content: Im looking to identify and source the component labeled as L8512 in this image. Its on an Ipad 6th Gen A1893 model. the component is blown and im not sure exactly what it is, or where I can source it. I will pay for any help in sorting this out!!! Thanks in Advance!

author: pdjames14
author_rank: Newbie
timestamp: December 13, 2021, 06:05:31 am
content: https://imgur.com/a/NSJNeti

author: fzabkar
author_rank: Super Contributor
timestamp: December 13, 2021, 06:52:13 am
content: It's an inductor. I would expect that the associated components, most likely a DC-DC converter or MOSFET, would also be damaged. There is a real risk that the load ICs may be damaged as well.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: December 13, 2021, 11:52:20 am
content: it's likely area of DC mulplier i.e. array of repetitive DC doubler by C pumps methodjust by E comp. labelL is an inductor, Y is a crystal, C capacitor
ipad mini 1 startup  - Page 1
Forum section: electronics / repair

author: leewald
author_rank: Newbie
timestamp: May 08, 2019, 03:17:32 am
content: New to this forum and just dabbling in repairing tablets and phones.I've got an Ipad 1 mini and really need to get some files off of it. Can't power it on tho. my question is this: does the iPad need the main charging port connected in order to power on? someone tried to replace the charge port and ripped a bunch of pads off. I've charged the battery by just connecting power directly to the battery but can't power it on. was wondering if it needs the charging port connected in order for it to turn on?

author: sokoloff
author_rank: Super Contributor
timestamp: May 08, 2019, 03:30:58 am
content: A charged iPad will definitely turn on without being plugged in.

author: leewald
author_rank: Newbie
timestamp: May 08, 2019, 04:27:34 am
content: yes i believe that too, but what about without the charge port. if the whole charge port assembly is missing?

author: notsob
author_rank: Frequent Contributor
timestamp: May 08, 2019, 04:52:23 am
content: for some basic info have a look at ipadrehab on youtube. I think Jessa also has info available on her website as well

author: neil
author_rank: Contributor
timestamp: May 08, 2019, 09:50:29 pm
content: notsob is right to point you toward Jessa's video collection on YT. Two of her videos that might help are "Battery data lines--how water damaged batteries kill phones with error 26" and "iPad mini suddenly won't turn on? Change Power Management ic".
ipc level  lifted pad repair - Page 1
Forum section: electronics / repair

author: ant17
author_rank: Regular Contributor
timestamp: July 06, 2022, 11:23:47 pm
content: hi guys in doing some repairs i have come across a few lifted pads and i have tried using pad strips to replace a pad using a green uv curing solder mask method. but have had limited sucess so i looked up the ipc standards for rework and found they use an epoxy but they don't say what one. has anyone had great sucess repairing pads more permanently with epoxy and what one was it that you used

author: C-47
author_rank: Regular Contributor
timestamp: July 07, 2022, 12:40:12 am
content: I'm in the same boat on pad repair, so far Permabond 920 at least on paper, looks good and doesn't cost a fortune, but yet to try it, as awaiting some answers relative to shelf life from the supplier here in Oz, temp rated to 250 deg C. Also keep us posted if you also find something. Alan.

author: ant17
author_rank: Regular Contributor
timestamp: July 07, 2022, 03:24:20 am
content: i have heard circuit works cw2500 can take heat as high as 316 degrees for short periods about 28 dollars aud havenot tried it yet
iPhone 11 battery connector pinout - Page 1
Forum section: electronics / repair

author: 2X
author_rank: Frequent Contributor
timestamp: July 09, 2023, 03:36:40 pm
content: Hello,I measure the battery of an iphone 11 and I measure in all pins 0V. Does anyone knows what voltage I have to measure in every pin (attached photo)? On android batteries where have 4pin one is Positive, one GND, one Battery Status and one Battery Temperature. On this battery there are 6pin.

author: Jane
author_rank: Frequent Contributor
timestamp: July 12, 2023, 07:38:10 pm
content: You'd better ask in a forum about cell phones e.g.https://forum.gsmhosting.com/vbb/f1086/

author: Alfi1966
author_rank: Newbie
timestamp: July 14, 2023, 07:22:40 am
content: You will not measure a voltage when unconnected. If the data lines are not talking to the charge controller the FET's in the battery pcb will not open.Found some info here. Hope it helps:https://logi.wiki/index.php/File:iPhone_11_Connector_1.jpg

author: 2X
author_rank: Frequent Contributor
timestamp: September 17, 2023, 08:06:21 pm
content: With only connected the connectors 1 & 2 the current that draw the iphone is about 500mA (if I disconnect the connector 1 the current falls to zero). This current is normal with olny these connectors connected? Also, there is a way to fix the Charging Flex (if it is indeed the problem there)?

author: 2X
author_rank: Frequent Contributor
timestamp: October 11, 2023, 09:02:51 pm
content: Finally I changed only the LCD screen and worked flawless.
iPhone 7 question on audio ic - Page 1
Forum section: electronics / repair

author: CoopedUp
author_rank: Regular Contributor
timestamp: October 23, 2019, 04:21:28 am
content: I have this iPhone 7, it boot loops. There is no shorts on the bb power chip so after more looking could it be the audio ic? There's a small chip in the edge of the ic, I'm not sure if it was there before or if I accidentally chipped it. Would recalling or reflowing the chip potential fix it, am I missing something, would I need to jumper one of the pins, could I buy a new recalled one? If anyone knows anything about iPhone 7 repairs I would gladly take advise. Thanks

author: CoopedUp
author_rank: Regular Contributor
timestamp: October 27, 2019, 04:16:49 pm
content: Still troubleshooting but on other news. i fixed a MacBook air with a short on pp4v something or other. It ended up being a clump of capacitors that were shot.
iPhone NAND BGA110 pinout - Page 1
Forum section: electronics / repair

author: fzabkar
author_rank: Super Contributor
timestamp: November 09, 2021, 09:59:15 pm
content: Does anyone have a BGA110 pinout for the NAND flash memories used in iPhones?Typical NANDs are listed on this page:https://multi-com.eu/,details,id_pr,22521,key,jc-p11f-bga110-programmer-for-iphone-8-8-plus-x-xr-xs.html

author: rvalente
author_rank: Frequent Contributor
timestamp: November 09, 2021, 10:29:29 pm
content: Quote from: fzabkar on November 09, 2021, 09:59:15 pmI know nothing about iphones, but I'd try to PM some utube channel, specially those who support the right to repair act. E.g ipad rehab, they may send you a schematic

author: hpibmx
author_rank: Regular Contributor
timestamp: November 10, 2021, 12:12:29 am
content: Quote from: fzabkar on November 09, 2021, 09:59:15 pmYou can download phoneboard it’s free and the have it there models using this nand.here is picture of it though.

author: fzabkar
author_rank: Super Contributor
timestamp: November 10, 2021, 05:55:58 pm
content: Many thanks.
IR1155S direct equivalent - Page 1
Forum section: electronics / repair

author: suntime
author_rank: Contributor
timestamp: March 28, 2025, 10:40:03 am
content: Hi,Does anyone know if there is a direct equivalent to the IC IR1155S?Since the IR1155S is discontinued and I need to repair powered speaker power supplies, I need to find some alternative.Thanks.

author: Swake
author_rank: Frequent Contributor
timestamp: April 02, 2025, 06:25:56 pm
content: Try the Aliexpress route. OK, this will be a little bit of a gamble of course given their reputation, but it is a 5€ gamble. Not the end of the world and if you carefully select a seller with good reputation and lots of sales, chances are high you'll find a working chip.

author: Vicus
author_rank: Regular Contributor
timestamp: May 10, 2025, 05:56:20 pm
content: I have the same request. And no, thanks but Aliexpress is not an option.

author: JoanBS
author_rank: Contributor
timestamp: May 10, 2025, 07:33:25 pm
content: Have you tried at RS-USA?https://us.rs-online.com/product/infineon/ir1155strpbf/70608184/or Heisener:https://www.heisener.com/ProductDetail/IR1155STRPBF

author: Vicus
author_rank: Regular Contributor
timestamp: May 10, 2025, 07:56:45 pm
content: I'm in Italy. RS italy report it as obsolete, not available.
IR2153 based SMPS repair + checking the IR2153. (Class D amplifier).   - Page 1
Forum section: electronics / repair

author: Yamin
author_rank: Frequent Contributor
timestamp: April 19, 2021, 11:28:36 pm
content: Hi guys, I've got in a Proel stage 4 class D amplifier in for repair. The fuse blown and I measured a short upstream from the bridge rectifier +Ve and -Ve. The two shorted components were the High and Low Mosfets. Gate-drain-source shorted on both. After removing the two mosfets the short has cleared when measured from the rectifier.I haven't figured out the root cause for the failure but I have measured one dual diode on the secondary side (channel 1) which is shorted. I would need to further investigate.My question is what other things I should look for while trying to fix this? I don't want to be just replacing MOSFETs just for them to blow up. What would be the best strategy?Could this short on the secondary side cause this kind of failure of the transistors?I tried to look for schematic for the model but couldn't find one, by the looks of it it looks like a standard IR2153 circuit with feedback.Thanks for the help.P.s: there is some kind of 'oilish' substance on the dual diodes on both the channels.

author: Yamin
author_rank: Frequent Contributor
timestamp: April 20, 2021, 10:07:18 pm
content: In addition to my post 1, I also wanted to ask about how to check the IR2153 using an external power source.At this point I have got the shorted MOSFETs out of circuit. I soldered to wires to VCC and COM pin of the IC and applied 10V from a bench power supply.I measured the voltage at Gate - Source pads for the high and low transistors.High = 0.0V (G---S)Low = 4.9V (G---S)I haven't got access to an oscilloscope at the moment but its my understanding that I should be able to measure something around 1V or something if its properly switching.First question is whether I'm doing this right?Second question is can I assume that the IC is toasted?Visually the IC looks okay and the diodes and resistors to the gate measures out ok.
IR2153 / LM311 class D amplifier repair - Page 1
Forum section: electronics / repair

author: Herschel
author_rank: Regular Contributor
timestamp: June 23, 2025, 05:36:04 am
content: I bought a 400watt(not actually 400watts) class D audio amp which is based on IR2153 and a LM311 comparator. So, I was running it on ±42 volts(max it could handle is ±45volts), also i noticed that the 13005 transistor which regulates supply for ir2153 gets really hot. But I never mid about that because i was running it below the ±45volts limit. one day when I turned it on, the amplifier just stopped working.found out to be the 13005 transistor shorted out, damaging the IR2153, 2N5401 and overloaded the lm311 comparator which eventually got damaged. But there wasn't any magic smoke. later I replaced all damaged parts and upgraded the 13005 to 13007 transistor. now i can even run it at ±56volts.But now when i tried to increase the volume, the low frequency part of music starts to get crackling for some reason.first I suspect it was of fake Lm311 or IR2153 or 2N5401 i replaced with but not(all the chips except the power mosfets were sanded out to prevent servicing), I tried changing them with different batches but no difference.So I upgraded the 10uf capacitors powering the LM311 to 100uf but nothing changed.I was running it on ±56volts but nothing was getting warm except the 13007 transistor I replaced.is it something to do with the snubber network? it doesn't had one. the same amplifier is reviewed on YouTube by multiple people, but they supply it with ±40 volts like i did before. I dont remember, it slightly crackled at full volumes. but i thought it was due to a weak powersupply...I did add snubber networks to each of the mosfets and the problem only appeared at higher volumes than beforethe circuit diagram i attached(clossest one I could find) has a mje350 transistor, this amp had a 2n5401. the output seemed to have a 2x 1uf capacitor instead of 3