820 3332 A Kernel panic on boot

[Sr. Robot]

Hi, got an 820-3332-A that kernel panics when botting OS. I cleaned old solder on U8900 and replaced with new one. It solved the problem at first but then it came back. I replaced the solder again but to no avail. There's continuity from all pins of U8900, the only trace i cannot check for continuity is GFXIMVP_UGATE1.

U8900:

GPUVCORE_EN: 3.32 v

PPVIN_S0_GFXIMVP_R: 12.52 v

GPUVCORE_PGOOD: 3.3v

 

[2informaticos]

Mentioned trace is probably good.
An high-MOSFET with floating Gate will get burn usually.

 

[Sr. Robot]

Do you mean the Q893´s mosfets? How can i find the bad one?

 

[2informaticos]

If GPUVCORE_PGOOD has correct value, then you also have good GPU core voltage.

Test if kernel panic comes in safe mode too.
Also try Windows Live, or Linux.

GPU disable is easy to do on this board.
Trying that will confirm where is the problem.

 

[Sr. Robot]

It boots in safe mode, i enabled the graphics switching option and now it boots normally, did a gpu stress test and it didnt crash.

Upon turning graphic switching back off, it still boots all the way without crashing.

 

[2informaticos]

Then bad GPU...

 

[Sr. Robot]

Yeah, seems like it. Thanks