[SOLVED]820-3115 Fan spins on and off cyclically

[dukefawks]

None of the components you listed will affect the board from turning on and giving a display.

 

[jadao]

You are right, I replaced all components listed and everything was working ethernet, audio and so on.

Internal LCD didn't show backlight, and found out LP8550 and c9714 c9710 burning hot. Unplugged power and found out 0.008 short on PP5V_S0 rail.
It was LP8850 internally shorted, when removed the chip I found out precisely VLDO input shorted to gnd, Vin was fine but they are tied together in apple designe. Replaced the chip and everything ok. This area was totally clean!
Passed all EFI/OS.

I think initial issue was PP5VS0 shorted by lp8850, maybe without lcd plugged in, LP8850 didn't draw current that's why fan was able to spin and sometimes speed was dropping and even restarting cyclically.
...
But since it was so clean I can't believe this happen just like that, I noticed the fan connector a little bit messed so maybe a short occured from the fan killing LP8850...

You can close this post since it is solved!