820-00164-A Green light, fan spin, no boot.

[Sr. Robot]

Hi, hot an 820-00164-A board with no visible damage, green light and fan comes on, but no image, chime or boot. Doesn't boot on SMC bypass mode.

Replaced BIOS chip, no change

PPVCC_S0_CPU: 1.8v

ALL_SYS_PWRGD: 3.3v

SMC_RESET_L: 3.4v

 

[2informaticos]

Do you get PLT_RESET_L?
Did you test the board alone on the desk?
How the fault appeared?

 

[Sr. Robot]

PLT_RESET_L is 3.3v

User says he was just using it and it shut down.

 

[2informaticos]

Did you test USB activity on both ports?
Check all voltages from page 11.

 

[Sr. Robot]

Yes, USB ports have power.

All voltages from page 11 present.

 

[2informaticos]

"USB ports have power"
I didn't ask that.
You have sufficient time in the forum, to know how to check for USB ACTIVITY (not power).

 

[Sr. Robot]

Yes, im sorry.

It has USB activity.

 

[2informaticos]

Then the board boots.

Check for external video.
If needed, force it disconnecting internal LCD.