820-3209 chime but no boot


New member
Hello guys,

I just got a new board which has no apple logo on startup. It chimes, video is there, the fan is spinning and VCore is present. But it doesn't boot.
When I measure the power rails, I get only 0.8V on PPVCORE_S0_CPU_REG (instead of 1.25V). I thought there could be an issue with Q7510 and Q7520, so I replaced them but nothing changed. Does someone have a clue?

Thanks a lot!!!


New member

thank you, you were right! By pressing the alt key, I was able run the ASD EFI Test which passed (after 1 hour - slowest part of the test were the memory tests).
The thing now is, that I can't install OSX because its so so slow. The mouse is lagging and everything takes way too long.
When I check the sensor readings in the ASD EFI, I can't find a sensor which seems not normal - everything looks fine.
Does anyone have an idea what could cause this?

Thank you!


New member
Ok thank you, I forgot to mention that the battery was dead because I thought this couldn‘t be the problem.
I will put in a new battery and keep you informed.

Thanks for your help!