QN75QN85BAFXZA no backlight

[howardc64]

2+ year old TV with many (720? 65" version has 720) mini LED dimming zones. TV boots, has sound, panel picture can be seen with flashlight. No backlight. No TV model sticker on rear panel (Maybe Samsung service removed it, read below). Found the model # through the PSU and zoned LED driver board numbers.

PSU has a click near LED output circuit at 1 second interval, sounded like the 4x barrier rectifier area. Protective pastic liner under PSU shows heat signature on the Schottky Barrier Rectifier in this circuit. Found a shorted diode (2 diode per rectifier, failed rectifier labled...

[davidebeatrici]

Before proceeding with a component level repair, the usual troubleshooting process was followed:

1. Disassemble and unplug everything except the power connector.
2. Replace RAM.
3. Replace CPU.
4. Rewrite BIOS.

Unfortunately the board was still stuck with a 0.75A power consumption at 19V.

After reflowing both GPU and north bridge in one shot (it can't hurt) there was an instant improvement with a constant 1.75A power consumption, but I immediately noticed smoke and the typical smell coming from the GPU area.
I thought to myself "Well,...

[2elw]

Hey,
Does anyone have a schematic or boardview for the HP Elite x2 G4? Motherboard shows "EMP20 LA-G931P". I've gotten 200 of these from my employer to unlock and its been hell since the EC rom is on the back of the board, im trying to find test points or any way to communicate to the EC or its rom without having to dissasemble the whole thing just to get to the back.
Thanks.

[CMCM]

Hello Everybody,

Trying to repair a power supply from a Russound CA4 Multizone Controller (picture attached)

Russound no longer supports it but were kind enough to provide a schematic of the power supply (pdf attached).

The outputs marked 12v and 20v are all measuring only 1v.

The board is clicking, which I think means it is in something called hiccup mode when the flyback transformers switches because of an internal problem or something else on the board Overloading it.

The capacitors physically look clean (no bludgesor leaks) and...

[max2711]

Hi,
i need EC dump for
Lenovo Legion Y540-17IRH-PG0
NM-C541
IT8226E-192
Thank You

[kuba2102]

Hello people. I have undertaken an upgrade from 256GB to 512GB. I have another A2681 board that I sourced NANDs, resistors and capacitors from. Yet when I try to restore the firmware in FDU mode I get the error 0x23 (35) (error formatting the NAND). Could it be the faulty NAND or I have missed something? Thank you...

[circuito]

Hello everyone,

I got a APC UPS SRT2200XLI showing General system error 0008. It's supposed to be related to the logic power supply. I checked all I could, but because of lack of documentation I'm going blind.

Any help will be appreciated.

Daniel






...

[Stachujones]

Hello i have a problem with a ThinkPad X280 with NM-B521 Motherboard, laptop doesnt power on
I dissasembled IT and started Basic trouble shooting
+20v is getting to board so power delivery circuit is working
Next i started looking on the board and i felt a burning hot chip its BD4179 "ThinkEngine"
I desoldered it, no more chips are getting hot
But i founded that on the capacitor marked on the picture there is 0.8 ohm short to ground and it's not capacitor, after desoldering it it's Still 0.8 short

Could anybody help me with fixing this laptop...

[Gado229]

Hello everyone, I have an MSI MS-15P3 Pulse 16 AI C1V that boots, doesn't display, and then the fan spins rapidly.
Can you help me find a working file to flash?
The old main BIOS file is attached.

MSI MS-15P3 Pulse 16 AI C1V
SN: K2411N0110648...

[Chivo77]

hello friends, I have a DELL LATITUDE 5420---MODEL P137G, ST 20TFKN3 LA-K491P REV:2.0 (A01) and its quite a challenge. It powers on with the battery disconnected, lasts on for about 15 secs, and then shuts off. It does the same with battery only (no adapter). With battery and adapter it sometimes starts after hitting the button several times. It displays nothing in every case. Since only the Boardview is available, I guided myself with schematics similar to this laptop (I'll add them down).Some measurements:

1- After receiving power SIO_SLP_S0# goes high and never changes.
2-every...