hybridfree/eevblog-posts huggingface dataset:
Dell monitor PSU Ilpi-395 V.a  491a012f1400h03 - parts recognition  - Page 1
Forum section: electronics / repair

author: sdancer75
author_rank: Frequent Contributor
timestamp: August 10, 2024, 01:02:30 pm
content: Can someone take a detailed photo of the burned parts on the downside surface of this dell's monitor PSU Ilpi-395 V.a 491a012f1400h03 ?

author: DavidAlfa
author_rank: Super Contributor
timestamp: August 10, 2024, 01:14:25 pm
content: New one for just 11 euro:https://www.aliexpress.com/item/1005006291283437.htmlThey seem to be 2R2 resistors, bu when these burn is due a major failure, so check the transistors, diodes, etc.

author: sdancer75
author_rank: Frequent Contributor
timestamp: August 10, 2024, 02:13:54 pm
content: I have already ordered one from AliExpress thanks.Yes, I am pretty sure that all neighbor components have burned, I was just trying to recognize some of them until I receive the replaced one.

author: MathWizard
author_rank: Super Contributor
timestamp: August 12, 2024, 06:11:34 am
content: So it looks like a 3-terminal mosfet with some high voltage on it, and was it 2 source resistors in parallel that got toasted ? Do you know the supply voltage for the mosfet ? The gate drives on a lot of these types of things are all pretty generic, and the same.Was it a main's powered Dell, so with some internal step-down type converter, or did it have a power pack ? Or was it a mosfet in a latter stage, running the backlight voltage rails ?Oh nevermind I didn't look at David's post pic with the main's plug.
Dell Optiplex 390 Desktop PC - Page 1
Forum section: electronics / repair

author: Carl E
author_rank: Regular Contributor
timestamp: June 29, 2020, 08:23:16 pm
content: Hello,This forum was so helpful in fixing a 2231 O'scope, I thought I'd try the forum again. My Dell Desktop died.It starts up for about 2 seconds and then turns off. I have to push the start button several times before it wakes up. I've replaced the Cmos battery and that didn't fix it. I'm ready to buy a new supply but I'm hoping someone may have a suggestion of anything else to check before I lay out some cash.Any help is appreciated.Carl

author: up8051
author_rank: Frequent Contributor
timestamp: June 29, 2020, 08:45:29 pm
content: Probably dried capacitors in the power supply.I had similar symptoms in the Dell Optiplex 755, five capacitors replaced and PC works agin.

author: Carl E
author_rank: Regular Contributor
timestamp: June 30, 2020, 12:07:11 am
content: SOLVED,Well it looks like this is a glitch in the ""I didnt ask for this software update that you just rammed down my throat'. After removing the power cord for 30 minutes, it booted like normal. I did check all the voltages on the power connector and they were in spec.Bad Microsoft !!Thank you all for the reply.Carl
DELL P2416Db LCD monitor LED backlight HELP please - Page 1
Forum section: electronics / repair

author: davebullock
author_rank: Contributor
timestamp: January 24, 2022, 03:58:39 pm
content: HiCan anyone help me please with my broken Dell monitor LED backlight SMPSU please?My monitor went dead and I quickly found that the on board mains fuse had blown.I checked all the usual suspect, mains bridge, HV capacitor switching MOSFET and all were OK.So I then began looking at the LV side.There is a 16 pin DIL SMPSU? IC that seems to power the LCD panel ( LTM238DL01-C01) LED backlight system.It has a mass of SMD components around it but it drives a power MOSFET with a 'catch diode' that supplies the LED's through a BLE-6PINS-CCAACC connector.I found the power MOSFET completely short circuit.Expecting a short circuit on the embedded LEDS in the LCD panel I measured all combinations of the 6 wires and they all seemed open circuit.So, suspecting the MOSFET died of old age I replaced it and the on-board mains fuse.Sadly the MOSFET just went short again but this time burnt out the pair of R33 source resistors (connected to GND) and the X10 (12.4 Ohm?) gate series resistor!I am now stuck.The DIL16 SMPSU/LED controller IC has no markings, I can't find any power supply schematics for my Dell P2416Db monitor.Can anyone help me please?Thanks in anticipationDave
Dell PA-1131-02D2 Power adapter repair - Page 1
Forum section: electronics / repair

author: toza27
author_rank: Newbie
timestamp: November 30, 2023, 10:44:33 pm
content: Hi.I'm trying to repair a Dell laptop adapter model PA-1131-02D2, and I can't find anywhere a circuit diagram or datasheet for the LTA301N, which is the main chip on the board. The problem with the adapter is that it has a fluctuating output. I would be grateful for a link or advice.
Dell Precision 5570 Repair - Page 1
Forum section: electronics / repair

author: CoopedUp
author_rank: Regular Contributor
timestamp: March 08, 2025, 09:29:54 pm
content: Greetings, I am making a new topic as I fell like I need to start over. So my laptop I bought has had a shorted capacitor and blew out some ferrite beads. I fixed all of that just to find out the GPU seems to be shorted out. I removed the coils for its power supply and when I got the battery put back into the laptop and plugged it in I was able to get the keyboard to light up and I saw a very dark faint dell logo. I assume this means it is trying to boot with the integrated graphics but what I want to know is why is it so dark and ccan I fix it?

author: Messtechniker
author_rank: Frequent Contributor
timestamp: March 08, 2025, 10:30:15 pm
content: Seemingly there is no display backlight. So first check the supply voltage for the backlight.

author: CoopedUp
author_rank: Regular Contributor
timestamp: March 10, 2025, 11:03:19 am
content: after a bit more messing around I was able to get it to pop into the bios and display but the keyboard doesnt work and it only seems to do anything when plugged in. the bat light just blinks orange when I try to turn it on unplugged on the battery alone
Dell Precision M6600 USB port boom! - Page 1
Forum section: electronics / repair

author: Jester
author_rank: Frequent Contributor
timestamp: July 06, 2022, 06:55:32 pm
content: I just purchased this camera from Amazon :https://www.amazon.ca/Camera-Charger-Hidden-Reader-Included/dp/B097P9N5TP/ref=sr_1_10?crid=3VIXK6UKTHICJ&keywords=Spy+Camera+-+Hidden+Camera+-+USB+Charger+-+Hidden+Camera+Charger+-+USB+Charger+Camera+-+Surveillance+Camera+-+Hidden+Spy+Camera+-+Hidden+Nanny+Cam+-+Full+HD&qid=1657133323&refinements=p_85%3A5690392011&rnid=5690384011&rps=1&sprefix=spy+camera+-+hidden+camera+-+usb+charger+-+hidden+camera+charger+-+usb+charger+camera+-+surveillance+camera+-+hidden+spy+camera+-+hidden+nanny+cam+-+full+hd+%2Caps%2C85&sr=8-10It’s mains powered and I was stupid enough to plug it into my Dell laptop without testing the voltage on the USB connection. The instant I plugged it in, there was a fairly large arc and the laptop shutdown.Looks like the USB port I plugged into is part of the motherboard.I’m not optimistic, anyone know how to troubleshoot this?

author: abdulbadii
author_rank: Frequent Contributor
timestamp: July 09, 2022, 04:59:18 pm
content: There some n-Port USB Hub IC directly connects to the USB jackcheck, likely broken some of it
Dell Printer Keypad repair (C1765nfw) - Page 1
Forum section: electronics / repair

author: XPModder
author_rank: Contributor
timestamp: May 05, 2023, 11:15:07 am
content: Hello,I have a Dell C1765nfw multifunction color laser printer. This printer is working perfectly fine with the exception of the buttons, which do not work at all.The printer does not have a soft power button, but rather a good old power switch, which is not part of the keypad/display assembly and obviously works fine.I got the printer for free as 'not working' as the display was not working correctly a little while ago. I already repaired the display problem (found a cheap replacement display, as the COG controller of the original was faulty) and also replaced the ribbon cable from the main PCB to the keypad/display pcb with a new one, as the old one was delaminating... (yes, the replacement is the exact same pin pitch and count and is fully seated at both ends.)After fixing the display and flashing the newest firmware version, I found out that the keypad is not working. The printer does not respond to any button presses at all, no matter what button(s) I press.I have now also replaced a 74HC244 and a 74HC174 on the keypad pcb, as I suspected one or both of them to be bad, but that did not fix the problem either. I did measure the voltages on the supply pins and they seem fine. The 5V rail is slightly high, but still easily within tolerances.I checked all resistors and diodes, as well as checking for diode drops across the transistors, both on the keypad board and on the main board next to the corresponding connector and they are all fine.There is also no visible damage to any of the boards or components.As I was unable to find any good documentation on this printer, I do not have the schematics and have not (yet) gone down the rabbit hole of reverse-engineering the entire board.The photos are all of the keypad/display pcb. The orange ribbon goes off to the LCD and the white one goes to the main board of the printer. Its a one-sided board, so nothing on the top, apart from some leds, buttons and a connector for a buzzer...Any ideas what the problem could be?I hope its not something broken with the application processor on the main board, but I dont think it is, since everything else works just fine...
[Solved] Dell R610 Motherboard VRM repair - Page 1
Forum section: electronics / repair

author: gnif
author_rank: Unknown
timestamp: May 09, 2025, 03:24:14 am
content: Hi All,I have a Dell R610 that died with a blown mosfet on CPU1. I know this system is very old and not really worth repairing, however i'd like to give it a shot anyway and see if I can bring this system back to life.I have removed the blown MOSFET which removed a short on the CPU power rail, however I now need to replace it, and the driver IC which is clearly also blown (hole in it). The problem is, I can't identify the part.It's a 8 pin DFN package with the markings:747C9125If I can't identify it or source it, I guess I will just transplant one from CPU2 and run it with a single CPU, but ideally i'd like to recover it if I can.

author: amyk
author_rank: Super Contributor
timestamp: May 09, 2025, 03:33:09 am
content: L6747C

author: gnif
author_rank: Unknown
timestamp: May 09, 2025, 03:34:14 am
content: Legend, thanks!
DELL SE2416H - Page 1
Forum section: electronics / repair

author: Jane
author_rank: Frequent Contributor
timestamp: April 06, 2022, 05:53:23 pm
content: Hello ,monitor DELL SE2416HWhat do you think the problem, like that at the video below, is caused by?The monitor is only pluged in to mains ( no other input) and turned on.Anyone experienced a such problem?

author: bob91343
author_rank: Super Contributor
timestamp: April 07, 2022, 05:21:26 am
content: Some kind of oscillation, maybe due to loose mounting screws on a circuit board.

author: Rasz
author_rank: Super Contributor
timestamp: April 08, 2022, 08:44:52 am
content: glass-tcon connecting ribbon or internal glass defect, very low probability of tcon and zero probability of scaler board/input defect

author: Jane
author_rank: Frequent Contributor
timestamp: April 12, 2022, 10:14:00 am
content: The monitor works from the very beginning properly but only for one or two seconds only.On T-CON there is an very hot (shorted?) IC marked as SM4047 .Anyone know what kind of IC is that?Thanks

author: Rasz
author_rank: Super Contributor
timestamp: April 12, 2022, 11:14:59 am
content: same defecthttps://www.reddit.com/r/AskElectronics/comments/na3idv/trying_to_fix_my_monitor_asus_vc239h_need_help/SM4047 is a DC converter for multiple supplies running the panel, they are also called Gamma correction buffers, VCOM generators etc.example pinout for similar SM4053 parthttps://www.pinterest.com/pin/471541023488781596/what on the tcon boardGetting hot means something is shorted, most likely inside the panel or chip on flex buffers. Replacing this chip 99.9% wont fix the issue, replacing whole panel or one of the flexes by specialized shop will, but this is uneconomical outside of Asia (India-China).There are also hackers (india/russia/china, its a true dark art) able to figure out which line is blown and bypassing it manually - this usually results in slightly darker picture with slighly visible gamma issues, but otherwise still working monitor. Example:TLDR: buy a new monitor.
Dell U3014, LG panel, repair advice sought - Page 1
Forum section: electronics / repair

author: gjvc
author_rank: Newbie
timestamp: October 06, 2020, 11:39:50 pm
content: Hello,I have a Dell U3014 monitor, revision A04, manufactured September 2014. The display started malfunctioning about six months ago and it now looks like the attached picture. The vertical white section moves from side to side, which I assume is the artifact of the "no signal detected" alert moving around.I have attempted to repair this already by changing the timing controller card, but the output is the same before and after. Now I'm out of ideas (although I saw a video about replacing a diode on a similar Dell model), and I am now seeking suggestions from the good people here on how to fix it.For interest, the panel itself is made by LG, but I'm not sure of the model right now, because the back is still on the casing (it's pretty tricky to get off and on).Thank you very much for any suggestions or advice.

author: wraper
author_rank: Unknown
timestamp: October 06, 2020, 11:45:19 pm
content: If there are no issues with power coming to T-CON, then IMHO LCD panel is dead.
Dell XPS 13 9343 - Page 1
Forum section: electronics / repair

author: sauce
author_rank: Newbie
timestamp: October 06, 2022, 04:04:32 pm
content: Hi,I try to repair the motherboard of a Dell XPS 9343.The reference of the motherboard is LA-B441P.I think PQ201 is shorted so I need to replace it.But there is a missing component on the board someone could tell me the name I don't have the boardview only schematic.In red on the picture.Thank you,Eric

author: nvmR
author_rank: Regular Contributor
timestamp: October 06, 2022, 07:18:04 pm
content: OP, Not sure I understand your postThe red circled component is a capacitor, and it is there in the picture. If you fear it is shorted, you can desolder it and test it out of circuit, and also test the pads on the board - to see where the short is coming from.Are you trying to find out what is PQ201 ?

author: sauce
author_rank: Newbie
timestamp: October 06, 2022, 07:27:06 pm
content: Sorry the picture is not my motherboard, it's a picture from another post.On my motherboard this capactor is missing so I would like to know its value but there is no name for this capacitor on the motherboard.

author: nvmR
author_rank: Regular Contributor
timestamp: October 06, 2022, 07:55:14 pm
content: It isn't that uncommon to see missing ICs or caps on a board, look above PL701 in the left hand side of your picture. Usually, an extra capacitor in parallel won't dramatically change things, especially considering the big black electrolytical smd cap near it.Are you going to replace PQ201? Have you tried measuring voltages with the board turned on?

author: sauce
author_rank: Newbie
timestamp: October 07, 2022, 05:18:55 am
content: Yes the 3 capacitors are in parallel so I don't think it will be annoying if I don't change it.I bought this laptop dead it was in quite good condition so I try to repair it.No power, no LED.But one motherboard inspected there was missing at least 2 components. The capacitor (not so serious) and PL104 (very annoying - only 7VDC instead 19V for DC_IN) !So I replace PL104 for the moment by a simple wire.19V is ok but I had a strange think near PQ201 and charging chip BQ24777. The voltage on ACDRV was the same as DC_IN so not norma I think.I measure resistance between Gate and D1 and it was 60ohm it's seems low, isn't it ?So I removed it and order a new one.Is there something I can neasure on BQ24777 with PQ201 removed to confirm ?PS : sorry for my english I am french
DELL XPS 9570 burns MOSFET when using thunderbolt dock - Page 1
Forum section: electronics / repair

author: RJSC
author_rank: Regular Contributor
timestamp: September 03, 2021, 10:38:30 am
content: I bought a Dell WDTB19 Docking Station to use with my XPS 15 9570 (also bought used a week prior) but noticed the battery discharging all the way to 0% when using the dock and the laptop heating up abnormally next to the thunderbolt port.Then I found out about the PQ208 MOSFET burning up in this laptops after a BIOS Update.There are many other reported cases at Dell's forum:https://www.dell.com/community/XPS/XPS-15-9570-TB16-USB-Type-C-no-longer-charging/td-p/7317594/page/7On the Dell's forum, their solution was a motherboard replacement under warranty, but mine is out of warranty now.Dell doesn't seem to recognize it's their fault and at least warn users not to upgrade the BIOS and use a thunderbolt dock.How it looked at the start:After I desoldered the MOSFET (PCB is charred underneath and the big pad lifted)I am yet to understand how this happens.Below is a part of the schematic (page 57).PQ208 is part of a Back-to-Back MOSFET switch arrangement that connects the USB Type C Vbus to the the same part of the charging circuit as the DC barrel jack.Maybe during firmware update the microcontroller handling EN_PD_HV1 released the signal but I can't see how it would have burned the MOSFET since power flows from source to drain and it wouldn't be flowing through the body diode to heat the mosfet up.I would do some bodge wiring of a mosfet here, but this trace and MOSFET handles 6.5A to power the laptop and recharge the battery.The Drain pad is lifted, I dont know of any glue that will handle the reflow temperatures of a new MOSFET here.Do you have any suggestions for repair?Full PDF schematic is attached for looking around.

author: Fraser
author_rank: Super Contributor
timestamp: September 03, 2021, 10:48:49 am
content: This is indeed an unuasual fault and I regret that I cannot help explain it.I can, however, advise that Cyanocrylate glue (superglue) is used to re-adhere copper pads to a PCB and it does normally survive reflow temperatures despite a notional maximum temperature of 250C. I would suggest use of a soldering iron for reflow in preference to hot air, where possible, though.

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 03, 2021, 01:51:51 pm
content: Check the signal at the gate and PR288.If by any reasons it's not switching correctly, ex. floating, the mosfet is likely to blow up due overheating.
Dell XPS 9570 motherboard CPU voltage regulator magic smoke release - Page 1
Forum section: electronics / repair

author: TimSmall
author_rank: Newbie
timestamp: October 24, 2023, 07:10:35 pm
content: I have a Dell XPS 9570 laptop (~5 years old, Core i9), a few days ago one of the VRM mosfets had a really bad day. Image attached...I was running a compilation job on it at the time, and was out of the room. Settings were at their default with respect to cooling etc. and it wasn't undervolted. When I came back into the room, it was turned off, but still pretty warm. Had I been in the room I may have been able to power it down earlier, but maybe not - difficult to tell how quickly it went.I found the schematic online, and the package which let go was an OnSemi NCP302045 - "The NCP302045 integrates a MOSFET driver, high-side MOSFET and low-side MOSFET into a single package." - one of the 4 in a row which makes up a 4 phase VRM for the CPU's VCOREB. Helpfully, the 302045 includes over-temperature protectionLooking at the heat damage with reference to the 302045's pad/pin layout, it looks like this may have been a short to ground (so maybe a source-drain short on the low-side mosfet). That may have stopped the CPU vcore getting whacked with 5v.I'm pretty much assuming the degree of PCB heat damage is likely to have put this beyond repair, but just thought I'd get another opinion on that since the damaged area is right at the edge of the board. A replacement board is about €300, so I'd probably be up for diving in on the off chance...
Dell Z9100-ON AVR54 Bug? - Page 1
Forum section: electronics / repair

author: hurryman2212
author_rank: Newbie
timestamp: January 26, 2024, 12:30:35 pm
content: I cannot find any Z9100-ON AVR54 fix method (i.e. location of suitable faned-out LPC_CLK0 and 3.3V location to connect pull-up resistor) despite the fact the teardown (https://electronics360.globalspec.com/article/12270/teardown-dell-z9100-network-switch;See attachment too) of it shows it uses two SPI ROMs (probably boot ROM, not the SATA M.2 SSD) connected to probably-sourcing-LPC-clock Actel-Microsemi FPGA SoC & Dell has issued the advisory about AVR54 issue on this model too.Since I am getting the one with B0 stepping, I want to know how to fix it. Is it OK to put the resistor on any faned-out location of LCK_CLK0 (probably TPM header will be the easiest but I don’t know that 12-pin header is TPM one. I do have an oscilloscope to distinguish the clock source though) and 3.3V (probably one of M.2 pins)?
Dell/LITEON 53WG5 PS-3231-9DA PFC TOP PSU works for a few seconds and turns off - Page 1
Forum section: electronics / repair

author: karapuzo
author_rank: Newbie
timestamp: November 07, 2020, 08:21:59 pm
content: Hello,I would appreciate if someone could point me in the right direction diagnosing a fault with a PFC PSU and potential things to check.Dell/LITEON 53WG5 PS-3231-9DA PFC PSU , works for a few seconds and turns off using the relay. (under load or without load, same behavior).After that it will not turn on for about 30 seconds and the same behavior persists.The TOPSwitch TOP266VG chip is very hot, even without load. I suspect it goes into thermal protection mode or some other protection mode (unclear why).The capacitors are visually ok. Tested most of the capacitors out of circuit, all fine. Transistors are not shorted, rectifier ok, discrete diodes ok, the capacitor shows 380 volts dc (meaning boost and rectifier work).Didn't find dry solder joints, output voltage while the PSU is on is normal, 12v, 5v.Tried looking for the schematic but couldn't find it.Pictures attached, much appreciated.

author: karapuzo
author_rank: Newbie
timestamp: November 08, 2020, 06:57:35 pm
content: Couldn't diagnose it, will be looking for a small factor psu to replace it.Meanwhile I butchered an old ATX PSU I had lying around, fits like a glove.

author: e-newbie
author_rank: Newbie
timestamp: October 23, 2024, 10:40:31 am
content: Hi,I have exactly the same problem. Will probably purchase a new one.But actually I would like to use an old supply like ou did.The 8 pin header seems not to be standard. The white wires are +12V I think according to the ATX spec this is -5V!)? The violet one is +5V (standby) ?Kind regards

author: Harry_22
author_rank: Frequent Contributor
timestamp: October 24, 2024, 01:50:03 am
content: Hi!So two identical blocks have the same manifestations of a malfunction. The power supplies worked properly, but at some point they began to “deteriorate”.This may mean that the parameters of some element have changed catastrophically. Electrolytic capacitors are most susceptible to this, especially if they are installed near a heat source.
Delta ADP-185bf power supply - Page 1
Forum section: electronics / repair

author: donnos
author_rank: Newbie
timestamp: May 09, 2022, 01:25:12 pm
content: Hi All,i am a Mac repair guy, so i have a bunch of this 185W 12V power from IMAC that went bad from customers, I'm trying to repair these PS so that i can reuse them for other projects.Please Note that i'm good in dc electronics but not so in AC. watching several videos on how SMPS work and roughly get the idea which are the main components but still blur in most of other stuffI have roughly diagnosed the PS and found that the MOSFET(IPA60R199CP) blew and it took out together the Diode(S8JC Liteon) and the fuse. i got them all replaced and tested output, everything good so far, i get 12V at the output.Issue is when i connect the PS to a DC Electronic load, i'm only able to get as far as 12V 7A(84W) before the MOSFET blows again.I realised that the coil and Diode that i replaced is getting warm @60C even at 12W load.I have several known good PS that i can use to swap parts around to confirm which the culprit is.this PS uses a NCP1605 for pf correction and L6599AD PWM controllers. in order to find out which is the bad component, I have tried replacing above mentioned parts + full bridge rectifier + Highside smoothing capacitor(measured at 380V underload and tested no issues).Icing on the cake is that there is no schematic for this PS.the tracing i found so far bridge rectifier -> coil -> diode -> capacitor(rated 450v 68uf) in parallel goes to NCP1605 and source of IPA60R199CP.So i need guidance or indication where should i look into that is causing this issue.
Delta Electronics power supply-looking for info... - Page 1
Forum section: electronics / repair

author: bob47907
author_rank: Newbie
timestamp: December 10, 2020, 01:10:31 am
content: I have a handful of Delta Electronics DPST-1150AB power supplies. These were used in Cisco Catalyst 3750 switches, and I'm looking for pinout information. Thus far, I've not been able to find any technical information about these PS.Thanks for any help!

author: bob91343
author_rank: Super Contributor
timestamp: December 10, 2020, 01:42:20 am
content: Did you tryhttps://www.deltaelectronics.com/
delta elektronika SM 3540 capacitor replacement - Page 1
Forum section: electronics / repair

author: roggii
author_rank: Newbie
timestamp: September 11, 2022, 12:26:32 pm
content: I was in the process of recapping my SM3540 since one capacitor had already failed.It was there when I found a cap with 3 legs and I'm not sure if I can just replace it with a modern counterpart. Two of the legs are connected to the minus rail, so its job is to increase current handling? It is situated right on the output board.Type: 674D 820µF 50V DCI did not find anything to be special about this thing on the internet or am I missing something?I would go ahead an replace it with a normal electrolytic cap 820µF/50V/105°C.Maybe somebody can prove me wrong:)

author: TheMG
author_rank: Frequent Contributor
timestamp: September 11, 2022, 03:04:59 pm
content: The extra pin is probably for added mechanical stability, since it's a physically large radial cap. No indications that this is a dual cap or anything special.

author: roggii
author_rank: Newbie
timestamp: September 12, 2022, 06:51:11 pm
content: Yeah you were right. Tore it apart for fun, the pin is just connected to ground.

author: srb1954
author_rank: Super Contributor
timestamp: September 12, 2022, 10:12:54 pm
content: Quote from: roggii on September 12, 2022, 06:51:11 pmJust check the PCB layout and make sure the two ground legs of the the capacitor aren't used to jumper between two different parts of the circuit.
Delta Source - ADP-30GF - Page 1
Forum section: electronics / repair

author: veigalex
author_rank: Newbie
timestamp: February 14, 2025, 05:04:28 pm
content: Delta Source - ADP-30GFGuys, I have a power supply like this, it is used in a Cisco SG300-28, but it suffered a discharge and the Q2 exploded. I don't think of anything like that.The IC used is a uc3843b and the FET is a K2544.Would anyone be able to help?
Denon 1508 protection fault repair notes - Page 1
Forum section: electronics / repair

author: fixy88
author_rank: Contributor
timestamp: September 29, 2021, 06:42:54 am
content: Denon AVR-1508 going in to protection mode on power up. Checked power supply found 7815 regulator on power supply board faulty and outputting 22v. Replaced reg and also reflowed any suspect solder on board. Amp now working.

author: David_AVD
author_rank: Super Contributor
timestamp: September 29, 2021, 09:06:25 pm
content: Also quite common on AVRs of that era is bad 7915 regulators with KIA branding.

author: fixy88
author_rank: Contributor
timestamp: September 30, 2021, 04:59:37 am
content: Quote from: David_AVD on September 29, 2021, 09:06:25 pmThis was a KIA, but the 7815. They run them so hot, it's no wonder they failed. I've also had a later Denon with a failed 7805.
Denon AVR-1610 red light flashing protect mode successful repair - Page 1
Forum section: electronics / repair

author: fixy88
author_rank: Contributor
timestamp: March 09, 2020, 04:59:58 am
content: Just placing this here in case someone else is repairing this unit.Symptom: Amp goes into protection mode and red ring around standby/on button flashes quickly.Cause: In this case the middle 7812 regulator labelled IC1700 was faulty and 100uf 35v electrolytic capacitor C1702 was shorted on the small power pcb in the top left corner.
Denon AVR-1910 power amp repair - Page 1
Forum section: electronics / repair

author: Rutherberg
author_rank: Regular Contributor
timestamp: February 15, 2018, 10:53:53 am
content: Hi,I have a Denon AVR-1910 here with a pair of power transistors shorted on the front right channel (Q1201 & Q1202), resulting in blinking red led when powering up the unit.Is there other components to check/replace by default when power transistors are shorted ? I attached the power amp schematic.Thanks in advance

author: willb
author_rank: Regular Contributor
timestamp: February 15, 2018, 12:00:40 pm
content: I've repaired a lot of these Denon receivers with failed outputs. You definitely want to check R1231FR, R1232FR, R1238FR, R1239FR, R1236FR, R1237FR, and D1201/1202- Z1201/1202. The emitter resistors always go open on these, and I usually find at least one of the SMD zener diodes to be shorted.

author: mzacharias
author_rank: Frequent Contributor
timestamp: February 16, 2018, 08:08:14 pm
content: I could fix these and similar models all day long. Did warranty work for Denon for over 20 years. Retired now but I still keep a stock of those output transistors, some original zeners, etc and a few scrap boards around for the odd small parts. I miss doing these on a regular basis. I do occasional work for a couple shops in town but rarely any blown channels anymore.

author: rfengg
author_rank: Regular Contributor
timestamp: February 22, 2018, 11:49:25 pm
content: Glad you could trace it to the output transistors.As far as I know, the protect kicks in when the Safe Operating Region of the transistors is exceeded, thermal excess or when there is average DC on the speaker outputs.I fought a losing battle with my AVR 1512 which used to kick into protect randomly.So what did I do?Disabled the ASO_DET line which was the offending signal causing it to go into protect and have been using the amp fine for 2 years now......of course, with a fire extinguisher next to the 1512, just in case.............

author: apellegr06
author_rank: Newbie
timestamp: August 06, 2020, 12:24:56 pm
content: Hi,@Rutherberg Have you finally found the problem ?Because I have a similar one.RegardsAlain
Denon AVR-2312 CI Red Light Blinking - Page 1
Forum section: electronics / repair

author: jemp
author_rank: Contributor
timestamp: September 17, 2021, 10:59:23 am
content: I have a Denon AVR-2312 , since 10 years..a very fine amplifierLast week it went down after 2 minutes to red light flashing...the it went faster and faster..Seemed tot be a ASO Failure according to service manual...tried everything , check speakers and so on.. nothing worked.So opening and found a superbe article online after quite a while searching...https://yesthomas.com/Electronics/201702%20Denon%20AVR3312%20Blinking%20LED.htmlthis was my problem.. I put this here.. since it could help someone..So I repaired it for 15 cents...Tnx to this guy from Sydney, that I can't address myself to him directlyJP
Denon AVR-x2000 fault - Page 1
Forum section: electronics / repair

author: cpposteve
author_rank: Regular Contributor
timestamp: January 24, 2020, 01:07:44 am
content: Hi all.after a bit of help here.i bought this 7ch amp broke. and having a bit of a mare trying to fix it.i fixed the original fault with the help of the service manual where one of the ksa992f transistors went short circuit and kept blowing resistors.on powering it back up it now doesnt cut off after 2 seconds and flash red. but instead now it starts to blow the big transistors on the board.in the picture you will see two 22r resistors marked in pink. when powering the amp up it sits there happy for a while, then after about 5-10 seconds these resistors start to glow and pop, taking out the large transistors marked in orange. and while on its travels it takes out part of the resistor network in blue.its really bugging me as looking at the schematic it would apear to me there is a short on the 2sc3694 (Q445).but i have tested all 7 of these and they are working fine.amps are not my forte so any help in diagnosing this would be a great help.cheerssteve

author: mzacharias
author_rank: Frequent Contributor
timestamp: January 25, 2020, 01:09:56 am
content: Bias transistor 2SC3964, output transistors, diode string associated with the bases of the output transistors (probably at least two bad) all four emitter resistors. Check the remaining transistors and there may be burned resistors associated with them. If so replace those transistors and any such resistors.Check carefully for potential bad solder connections with the outputs to the main amp board.

author: cpposteve
author_rank: Regular Contributor
timestamp: January 25, 2020, 08:38:48 pm
content: cheers for your reply.the bias transistor all seem fine.the diode string is not fitted to this model.the emittor resistors are burning up along with the output transistors, which is the issue im having. i cant fathem out why they randomly popping when switching on,i have checked most of the other associated resistors and all seem fine. ive also checked all of the voltage regs and they all seem good too. im really stumpedsteve
Denon AVR X4400R  - Page 1
Forum section: electronics / repair

author: ats3788
author_rank: Contributor
timestamp: November 06, 2023, 02:51:26 pm
content: HelloI have a DEnon AVR X-4400R and due to a short circuit on the terminal.I have a scratching noise in the channel, the distortion factor is very high.I have all the datasheets from Denon.The question to you.Could this be the preamplifier or should I suspect the fault in the de-amplifier?Stupid me I dropped this Baby while we where moving.

author: Swake
author_rank: Frequent Contributor
timestamp: November 07, 2023, 09:06:23 pm
content: What terminal is short with which other?'scratching noise' on only one channel? or all channels? Also on the headphone output? Also on the tape record outputs or similar?What is the physical damage after the dropping?

author: ats3788
author_rank: Contributor
timestamp: November 08, 2023, 08:47:01 am
content: Thanks for answering I did not test the Headphone output.The Damage is not so bad, it is only the right Speaker Terminal Front to the right I will test the Headphone output and inform right here.

author: Swake
author_rank: Frequent Contributor
timestamp: November 08, 2023, 09:14:43 am
content: Before powering up again:If you think that broken speaker terminal has a short to something else, make sure to remove that short first. A short might damage the output transistors. It is possible that there is some form of short protection but that is likely not a perfect thing so don't count on it to save the output, certainly not in the longer term.

author: ats3788
author_rank: Contributor
timestamp: November 08, 2023, 09:37:53 am
content: I just tested the Headphone OutputI think it's OK I will Test it with a sinus Generator and my OzzyNo Shortcut on the Speaker Terminal anymore.Thank you for helping I have basic experience in ElectronicI know everything about it, but I can't read the circuit properly.I'm not in a hurry I still have my Onkyo Baby SR 600E.

author: ats3788
author_rank: Contributor
timestamp: November 08, 2023, 02:38:30 pm
content: That was a pretty well hint. I connected my sinus Wave Generator on the Input Chanel The Right Channel is Ok the Left channel has the noise can't even see the Sinus on my Rigol Ozzy.
Denon DCM-380 CD Player Dead (PS ok) - Page 1
Forum section: electronics / repair

author: fuzzoli
author_rank: Regular Contributor
timestamp: February 12, 2023, 02:42:58 am
content: I was given a Denon DCM-380 5-Disc CD player and it's observably dead. Easy, must be the fuse! Nope -- fuse is good, so...- +3.3, +5, +12, and -12v supplies all measure good, as do the two supplies going to the "Front Section".- The ICP-N38 circuit protection devices all measure within specs (about 0.4 ohms).- There is no response to any button presses, no visible motion of motors, and no other detectable sounds of gears or servos.There are /RST and PWDN pins on the main micro (IC502), so I was thinking a bad part was holding the proc in a reset/powerdown state, but that also does not seem to be true (/RST and PWDN are both a 5v). There is no observable waveform across the processor's crystal (I'm not even sure it would be measurable on the scope even if working).I was hoping for a quick repair, but it's not looking that way any longer.Any thoughts?The manual is here:https://www.manualslib.com/download/1258750/Denon-Dcm-380.htmlThanks!-Frank

author: shakalnokturn
author_rank: Super Contributor
timestamp: February 12, 2023, 10:03:07 am
content: You should see something on the quartz if your oscilloscope has sufficient bandwidth and your probe isn't loading it too much.No clock fits with your symptoms...
Denon PM-770 Amplifier - Page 1
Forum section: electronics / repair

author: EifX
author_rank: Contributor
timestamp: April 22, 2020, 12:54:02 pm
content: Hi there girls and guys,I am a little at lost with this amp. I am recaping the amp an came over some caps in the machine that are lower in capacitance then it is stated in the service manual and parts list. I took out of the machine 0,47uF/50v but the part list and schematic states 220uF/16v.Now the caps in the machine don't look very old (the amp is from 1984) but the company that makes these caps (Nippon Chemi-Con Corparation) is around sinds 1931. Even the printed icons on the pcb for the dodgy caps are much larger then the cap that was soldered in.Does anyone has some advice on how I can tackle this and determine what the truth is here?
Denon PMA 860 loudness switch - Page 1
Forum section: electronics / repair

author: aycaramba
author_rank: Newbie
timestamp: September 21, 2022, 11:26:53 am
content: Hey!I am looking for a replacement loudness switch because the old one is probably worn out and makes both channels play unevenly when pressed. Does anyone know where I could buy one?Thanks!

author: vf33184
author_rank: Contributor
timestamp: September 21, 2022, 11:54:41 am
content: Did you try to clean the switch with Deoxit or similar contact cleaner solution? It seems that contacts are dirty or oxidized.

author: aycaramba
author_rank: Newbie
timestamp: September 21, 2022, 03:40:13 pm
content: I will clean it soon, but first I wanted to ask if somebody knows where I can buy this kind of switch in case I destroy something
Denon SC6000 RJ45 Link socket - Page 1
Forum section: electronics / repair

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 03, 2024, 05:11:30 pm
content: OK, so I need to replace the RJ45 link socket on a Denon SC6000.After searching Mouser, I came up with this which is an identical size and footprint.https://www.mouser.co.uk/ProductDetail/960-TMJ0162GDNLOnly it doesn't work (and the right yellow LED is the opposite polarity of the original)A bit of Googling the data sheet shows the pinouts are clearly not compatible with the Denon configuration you can see in the photo of the PCB.https://www.taoglas.com/datasheets/TMJ0162GDNL.pdf.Section 4.1 shows the pinout.The Denon has I presume 4 pairs of data lines.Now this is when I realise that I don't have a clue about any of this, the RJ45 is not the Universal connector I presumed it was, and I'm not even that sure what T10/100 base blah blah is either.So the question is, what should I actually be looking for in my Mouser (etc) search parameters?What are Denon doing here?

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 04, 2024, 09:59:27 am
content: So I've managed to find almost what I'm looking for now.This datasheet has circuits C & D which appear to be very similar with what I pulled from the Denon.https://www.mouser.co.uk/datasheet/2/706/fastjack_gigabit-520265.pdfThey show Pin one as VCC, though in the Denon it is connected to ground along with pin 10.
DER EE DE-5000 LCR meter not measure capacity - Page 1
Forum section: electronics / repair

author: mikelv
author_rank: Newbie
timestamp: January 24, 2025, 07:51:16 am
content: Hello , recently I have adquired DE-5000 , but measuring capacity at one point, I lost the reading and could no longer take capacity measurements, although it does take the others measures correctly.Does anyone have schematics or what I can check?The capacitor I was measuring was discharged,but due to the fault,it seems that voltage was introduced.What do you think?thanks

author: benj38
author_rank: Frequent Contributor
timestamp: January 27, 2025, 10:29:08 pm
content: Can you successfully perform the short/open calibration procedure as specified in the user manual?

author: coromonadalix
author_rank: Super Contributor
timestamp: January 28, 2025, 02:16:35 pm
content: the de-5000 are based on 2 ic's solutionhaven't see schematics for themyou have some thread about the de-5000 if you do a search, you have some parts as input protection, but i think it's basic in a senseas to get them if they are blown, you have to ask Cirustek i think, apparently a member here got some from them ?

author: ass20
author_rank: Regular Contributor
timestamp: February 15, 2025, 09:40:58 am
content: you can use schematiс from mastech ms5308

author: coromonadalix
author_rank: Super Contributor
timestamp: February 15, 2025, 12:01:33 pm
content: do you have a link to it ? never saw any leaked one about theses models

author: JimKnopf
author_rank: Frequent Contributor
timestamp: March 05, 2025, 06:11:51 pm
content: @mikelv Open the device and have a look at the resistors below the DM5000 IC.I accidently tested a charged cap a while ago. I had to replace 2x 1000 marking resistor and 1x 01C and 1x 01D if i remember correctly.After that it worked like new.

author: MarkF
author_rank: Super Contributor
timestamp: March 05, 2025, 06:34:13 pm
content: Someone on the forum posted a schematic of the frontend awhile back.See attached.Edit- Oh, this is just for the power supply. Failure if battery is put in backwards???
DER-EE DE5000 CAL failure (FIXED) - Page 1
Forum section: electronics / repair

author: Lorenzo_1
author_rank: Regular Contributor
timestamp: January 30, 2021, 02:42:04 pm
content: My DE5000 LCR meter failed CAL repeatedly on Short setting, while passing CAL on Open setting. Had been working reliably for a couple of years and used frequently. Battery change made no difference and meter failed CAL the same way at same time with both the standard TL-21 short leads and the TL-22 tweezer set, which made me suspect the meter itself. Have always been careful to avoid testing possibly charged capacitors.After some exploration, Short CAL came good by inserting copper wire directly into +/- terminal connectors, bypassing the leads/3-blade adapters. Turned out both TL-21 and TL-22 leads had simultaneous soldering/wiring faults. The TL-21 set failed because of bad solder joints and a broken wire at both the crocodile clip and on the PCB inside the 3-blade connector. The TL-22 set failed from a broken wire on one of the two PCBs in the tweezers. The tweezer set took a few attempts to repair because the wires are quite fine and inflexible. Found it necessary to desolder all four wires and two ground sheaths, cut them all the uniform length and resolder. Refreshed solder joints on all the PCBs while I had them apart. A bit fiddly, but worked fine in the end.Thought this might be useful for others who use this meter.
Desktop PC Power Supply - FORGE - Page 1
Forum section: electronics / repair

author: 2X
author_rank: Frequent Contributor
timestamp: June 15, 2020, 06:37:55 pm
content: Hi,I had a power supply from a desktop PC where the 3.3V volt was 3V. After I measured the components that involved in 3.3V output and was ok (resistorw caps and diodes) and I decided to disconect the resistor where parallel with the output capacitor and worked fine... the resistor was the right value (according to the colours which had on it) when I measured with the multimeter... finally I put a 33ohm resistor (yellow circle) and works fine and the PC starts ok and keeps the 3.3Volt now. Does anyone know which is the use of these resistors at the output capacitors on 3.3V, 5V & 12V (yellow and red circles)?

author: TheMG
author_rank: Frequent Contributor
timestamp: June 16, 2020, 02:48:57 am
content: What was the original value of the resistor?Those resistors are there to ensure a minimum load on the outputs of the power supply.The fact that you changed the resistor value and now it works, is just a symptom of some other problem.

author: 2X
author_rank: Frequent Contributor
timestamp: June 16, 2020, 08:15:09 pm
content: Quote from: TheMG on June 16, 2020, 02:48:57 amThe old resistor was 10ohm. With multimuter I measured 8ohm. The new one that I put was 33ohm. Thanks a lot for the reply.
Desoldering Gun Yihua 948 vs Zhongi ZD-8965 - Page 1
Forum section: electronics / repair

author: hgryska
author_rank: Newbie
timestamp: August 30, 2024, 06:27:58 pm
content: I ordered both desoldering stations and could compare:Base StationPro 948: Good build quality with complete metal housing. Transformer for galvanic isolation.Con 948: Large and heavy. Transformer doesn't seem to have enough power and additional switch mode power supply for the pump can improve suction power.Pro 8965: Stylish and small due to switch mode power supply. Pump is decoupled from housing by springs and therefore very quiet. Gauge for suction pressure.Desoldering GunPro 948: 90W. Much better handling (shorter and thinner). Glas tube easy to remove for cleaning. Heater has more thermal mass. Heater exit pipe has much more thermal mass which minimizes clogging.Con 8965: 80W. Handliing not so good (longer, thicker, sharp edges of handle inlay). Heater exit pipe is longer and has less thermal mass with higher risk of clogging. Glas tube removal is pain in the ass due to long heater exit pipe.Conclusion:My ideal desoldering station would be a combination of the 948 gun and the 8965 base station. The 8965 desoldering gun sucks and is a show stopper. I decided for the 948 and plan the following mods:Install relay and MeanWell switched mode power supply RS-25 (12V, 2.1A) to drive the pump motor (output voltage set to 13.0V).Decouple pump from housing by 4 springs (5x25 mm, 0.7 mm wire diameter). The springs are connected to 4 studs in a spider configuration around the pump so that there is some clearence between pump and bottom.

author: geralds
author_rank: Contributor
timestamp: July 16, 2025, 12:47:13 pm
content: Even though an old post, have you done the mods to the 948 that you mentioned? What has been your experience with it? I am thinking of doing sth similar to my 948.Many thanks