tlough75
Member
I have on the bench an 820-3332, so it is an Early 2013 15". the first time I saw it on my bench the screen would randomly flicker and the laptop would crash. I resoldered U8900 and it seemed to fix it, but a week later it is back on my bench. According to the customer, after it is running for a while it would crash. I myself only got it to crash once with a GPU Kernel Panic error, saying something about "mux-reg 3" or something of that nature. I measured PPVCORE_S0_GFX_PH1 and it has 900mV even though the screen went black, but after the screen turned off. After few moments the whole machine would turn off. I noticed the battery has a "service me" label but I assume this is a separate issue. So far at idle, I am able to run it for the past hour without the SSD and no crashing. I don't see in "About this Mac" if this machine has a discrete GPU. Any Ideas? Or is the GPU toast?