820-2915-B Green Light, Fan Spin, No chime, No Video

[Sr. Robot]

Hello, hope you guys are all right.

So i have an 820-2915-B with charger light, fan spin, but no chime and no video (no mouse light). Theres no visible corrosion on the board. And i managed to turn it on once but no luck again.

PPVCORE_S0_CPU is 0.78v

U7400 shows no sign of damage at all, and CPUIMVP_VR_ON is 3.3v and PP5V_S0 lines are 5v.

What should i do next?. Could it be a bad CPU?

 

[2informaticos]

"PPVCORE_S0_CPU is 0.78v"
Looks like board is booting.

Did you check both USB ports for activity?
You can try disabling GPU in BIOS, to discard its failure.

 

[Sr. Robot]

Yes, i checked them both and no light on the mouse.

The GPU has failed long ago but it worked all right with software bypass. I cant disable it anymore because i cant even boot in safe mode. The LCD shows no image at all. Shouldnt a macbook 2011 still at least try to boot with a bad GPU?

Thank you.

 

[2informaticos]

VCORE starts with 0.78V, or drops from 1.15V after 5-10s?

 

[Sr. Robot]

I managed to turn it on, i noticed there was a corroded pin on the LCD connector, so i replaced it, and now it chimes and boots.

What i find weird is that there was no chime, no keyboard backlight etc, etc before the LCD connector replacement.