820-00165 fan spin, no chime, no image

[ajdoc]

Liquid damage on J6100 area.

Light on charger, no fan spin.
J6100 removed.
5V S5 was pulsing from 0V up to 5V every second.
There was short on PP5V_S4RS3 - C7550 was bad.

After that got fan spin, no chime, no image/bkl, USB activity works, caps lock LED off, CPU warm.

There was no corrosion around U6100 and diode mode reading are correct.
Just in case changed U6100 and U1900 and got quarter fan spin.

Any idea?

 

[2informaticos]

Check what happened to get quarter fan spin.
Start reballing SMC, once you've found corrosion not too far.
Check all SPI Bus Series Termination resistors and their traces.

 

[ajdoc]

R6131 on SPI line was bad - replaced and all works fine now.

Many thanks and have a great weekend