820-00164 light on charger, short fan spin, no chime.

[ajdoc]

Light on charger, short fan spin, no chime.

Found very small liquid damage on R7611 and C7616 which was burned out. Replaced and still same issue.

Got light on USB.

Any idea please?

 

[2informaticos]

USB mouse test is tricky.
If fan stops, I suppose board is not working.
Does the mouse get light if you disconnect/reconnect it?
Is alwaus better to test with OSX pendrive (with link LED).

Do you have voltage on all coils, including CPU?
Check at least for pulse on the coils...

 

[ajdoc]

"Does the mouse get light if you disconnect/reconnect it?"
Yes

Got stable 1.80V on PPVCC_S0_CPU at C1031

Voltage is stable on all coils:
L7310 at 1.80V
L7320 at 1.80V
L7430 at 1.21V
L7630 at 1.06V

 

[2informaticos]

Do PRAM reset, if possible.
If R7611 was open, that means overvoltage ocurred on 1V05 power rail.

"Is alwaus better to test with OSX pendrive (with link LED)."
Also check external video.

 

[ajdoc]

Cant do PRAM reset. Nothing happens. Fews secs and is turned off. No chime. Checked on ext keyboard and same story.
Nothing on ext display.

 

[2informaticos]

Try new BIOS.
You can also reflow PCH/CPU with good flux; just in case has some crap under...