Lenovo Legion 5 15ACH6H boot problem

[sopik78]

Hi friends,
I have a big problem with Lenovo Legion 5 15ach6h, MB Hy660 (661 ...) NM-D562 Rev 2.0.
Originally, the defective EDP cable found, also a defective LCD panel. After the replacement, the image goes to the BIOS, but it is not possible to boot the system, or install the system, always falls, or restarts directly. Occasionally different BSOD (attached in the attachment).
So far tested:
- RAM exchange
- disconnecting all peripherals
- Disconnect the battery
- I have another with a different defect, so the swap of KBC
- Another nvme disk, test in the second M.2
No change.

Any suggestion, what else to try, or where could there be a problem?

[sopik78]

Re: Lenovo Legion 5 15ACH6H boot problem

Schematic and boardview attached

Link to schematic -> https://www.badcaps.net/forum/troubl...-and-boardview

[Bonzas]

Re: Lenovo Legion 5 15ACH6H boot problem

it can be dead soc or gfx, just for make sure check all caps filter on gpu & gfx core. I got problem like yours before on ROG and Legion, First i assume dead gfx before i found culprit caps on gpu core fet

[mcplslg123]

Re: Lenovo Legion 5 15ACH6H boot problem

Very likely SOC fault

[sopik78]

Re: Lenovo Legion 5 15ACH6H boot problem

Thanks for the answers.
So GPU or SOC is not very good news, both are very hard to find and very expensive
I would need to be sure which one is faulty, but the GPU probably won't turn off so I can only test with the Vega chip.

In addition, a different solder is used on this board, apparently it melts at a much higher temperature than the usual PB free. Or is it only very difficult with Kingbo RMA 218 flux?

[mcplslg123]

Re: Lenovo Legion 5 15ACH6H boot problem

Yes, the solder is very difficult to melt on many gaming motherboards. I beleive its SOC or corrosion somewhere in S0 rails.

[ivanl]

hello, I have a problem with starting MB. 3.3v, 5V, 1.7V, 0.7V, and 0.2 (batt) work for me, after pressing the button, the light turns on, about yellow, but it doesn't go any further. on branch FBVDDQ man 0ohm, on NVVDD I have 0.23 ohm, no voltage. I'm guessing that the gpu or its memory is faulty, I tried to put 0.7 V into the fbvddq and it takes a maximum of 2.5A, but nothing heats up. advise what to try next? well thank you

[DeXXter]

Did u solve your problem? For what I know that laptop has an AMD cpu with fch integrated, so I don't think the chipset is the problem there. Did u tried using a linux distribution?

[DeXXter]

hello, I have a problem with starting MB. 3.3v, 5V, 1.7V, 0.7V, and 0.2 (batt) work for me, after pressing the button, the light turns on, about yellow, but it doesn't go any further. on branch FBVDDQ man 0ohm, on NVVDD I have 0.23 ohm, no voltage. I'm guessing that the gpu or its memory is faulty, I tried to put 0.7 V into the fbvddq and it takes a maximum of 2.5A, but nothing heats up. advise what to try next? well thank you

Did u solve your issue?, if you have 0ohm on FVDDW that's vram power supply short (and probably gpu short too).