820-00165 no backlight

[2informaticos]

So missing EDP_BKLT_EN.
BKLT_PLT_RST_L present?

Try PRAM reset 2-3 times.
Any history available?

 

[Neil250]

BKLT_PLT_RST_L present ----> 3.32V

No spill,

Initially, no fan spin.
Corrosion was noted at C7400 and C7425
Both replaced.
Now fan spin with dim back light.

PRAM rest no improvement

change U7701?

 

[2informaticos]

No pulse at all on EDP_BKLT_EN in the first seconds at least?
Check it when hear the chime.

 

[Neil250]

Replaced U7701
Machine now boots and works