820-2915 strange GPU behaviour

ALB-Repairs

Member
Hi
I have an 820-2915 that came in with no power. It had no signs of liquid damage, however 2 of the three GPU rails where dead short to ground. It had signs of an apple refurb previously.

i fitted a new GPU, shorts gone, however it very rarely produces an image at all. The fan spins up twice like other 2915's that recognise a gpu.

The confusing part starts here-
Regardless of weather there is an image it boots fully and gives a keyboard backlight. When i have had it displaying, it would boot white and then loose display, but rather than restarting it would continue to boot and remain on with a keyboard backlight, neither internal or external display works.

Ive reflown the VRAM, the GMUX, checked for missing components around the GPU and Vram, checked the power rails.ect.

I even pulled the replacement GPU off and checked the solder joints/site and couldn't see any issues. Im assuming this board has bitten the dust, but due to the obscure nature of this one i thought id ask.

Maybe it was something to do with the initial GPU being shorted? Id love to say i messed this GPU up, but ive done plenty of 2915's before and never really seen the strange mixture of faults this machine is presenting.
 

dukefawks

Administrator
Fuck those apple refurb boards. I do not touch them if they have 2016/17 GPUs as they have all weird failures like this. Avoid....
 
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