A1278- 820-2879-B Chime, FAN high speed, white light on, NO video, NO backlit

[lordhex]

A1278 - 820-2879-B Chime, FAN high speed, white light on, NO video, NO backlit

Hello,

I have a MBP Mid-2010, that powers on, chimes, fan starts spinning at low speed then turns on high speed. The white light in front next to IR sensor gets bright lit, after chime, dims a little but doesn't turn off completely.

It does charge, the light on the charger turns orange if the battery needs charging and green when done.

The screen backlit does not turn on, external monitor does not work either. Does not boot, at all.

The CAPS lock LED does not turn on/off.

It had liquid damage 10 years ago, however, was professionally cleaned and been working fine until couple weeks ago. I did take it apart, cleaned the logic board again, but still does not boot.
I did reset NVRAM/PRAM and SMC.

Any help would be greatly appreciated. I do have the board view and schematic (attached).

[ajbernasko]

Re: A1278- 820-2879-B Chime, FAN high speed, white light on, NO video, NO backlit

it should be a problem with the u1400, check shorts on U9000 pin 4&5, Q9807 pin 5. all does not turn and leaded to the u1400. A rework for the u1400 should work or just need to replace u1400

[lordhex]

Re: A1278- 820-2879-B Chime, FAN high speed, white light on, NO video, NO backlit

Thank you so much for your response. I will take a look again, right now its on a shelf. Few months ago was doing that, and in addition a resistor in the middle of the board was getting hot to touch (I forgot the numbers now) and that's (and other reasons) what probably was causing the fan to speed up to the max. Its interesting that it failed suddenly. One morning it stopped booting.