820-3330 Stuck on Apple logo

[Don Anton]

Hi,

This is a clean board.

How ever P!V5_GPU_S0 was not there. after replacing Q8360 and Q8361 I got 1.35v on this rail and it turned on.

It was working fine with out having any issue but start crashing with audio editing and now half way stuck on apple logo.
Before it crashed I check ASD OS test and it all passed couple of times. However Internal graphic test graphic were bit scattered.
YOu cant feel much heating on GPU rams or GPU as 2011 boards. As soon it turn on P!V5_GPU_S0 is 1.5v then after chime goes to 1.35v.



Any clue?

 

[2informaticos]

Some tips available on Internet to disable GPU on this board...

 

[Don Anton]

HI, I dont want to disable this chip as this is 2012 board. I have done many of them reprogamming MUX chip, but this one customer needs the dedicated GPU for external display. I can replace GPU on this but GPU seems to be good. P1V5_GPU_S0 is 1.35 as schemetics but saw on Louis videos it should be 1.5v?

 

[2informaticos]

Check the note about VID0/1 combination at page 78...