820-00840

[iFix]

Powers on on battery or on charger fan spins no backlight voltage and no chime...

 

[2informaticos]

Board turns on every time now?
Do you get USB activity, external video?

 

[iFix]

Yes turns on every time fan spins for a bit and turns off and CPU stays cold. No external and USB only the type c hub lights up but when i plug in a mouse nothing happens

 

[2informaticos]

"fan spins for a bit and turns off"
So doesn't really turns on, just trying...
When fan spins, check which coils get voltage.
Did you try known good BIOS?

PLT_RESET_L comes high?

 

[iFix]

Getting back to this one

I have on all coils voltage besides CPU and backlight. PLT_RST_L is 0v measured on R2014. Bios I haven't tried still

 

[iFix]

I just tried a new bios but still the same...

 

[2informaticos]

"I have on all coils voltage besides CPU and backlight."
Steady voltage, not pulsing?

 

[iFix]

No all steady like it's powering on and staying stable. PLT_RST_L comes from SMC right?

 

[2informaticos]

Before L7210/20, you must get voltage at L7370 and L7730; check that.
If yes, check U7100 voltage; pins 41, 42, 48.

 

[iFix]

L7730 i have 1v and on L7370 0v.
U7100 Pin 41 13v, pin42 5v and on pin 48 0.8v

 

[2informaticos]

You don't have ALL_SYS_PWRGD.
Check the power good signals of U7800 (1 OF 10) block.

Be aware, voltages generated by U7800 don't have accessible power good signal.
So check in pages 61 & 62 if all voltages are correct.

 

[iFix]

The client decided to replace the board. Thank you