Macbook A1466 820-00165 No Power. PPBUS_G3H is at 8.2V

[Instafixx]

Hello,
This macbook came in for no power. The board is clean . no corossion.

PPBUS_G3H is at 8.2V
PP3v42 is 3.4V
SMC_Reset_L is is 3.4V

Where do i start checking.

 

[2informaticos]

Check R7100 first.

Check AVREF_SMC and 1V25_S5_SMC
Do you have oscillation at Y5110?
Check when pressing power button too.

 

[Instafixx]

R7100 is okay.

Didoe Mode Reading is .543.
Voltage is 3.4V

AVREF_SMCis 3.3V
PP1V2_S5_SMC_VDDC is 1.23V

I dont have the tools to check oscillation.

1 more thing. i did not have the Magsafe light yesterday but today there is light on the charger

 

[2informaticos]

Do you get correct SMC_RESET_L signal no?
What is the exact PPBUS_G3H voltage (without battery)?

 

[Instafixx]

PPBUS_G3H is 8.19V Exact.

What do you mean by correct smc-reset signal ?

 

[2informaticos]

3.3V?

 

[Instafixx]

Yes its 3.3V

 

[2informaticos]

"I dont have the tools to check oscillation"
No need to use oscilloscope for that.
When Y5110 oscillates, you should find 1-1.2V DC voltage there.

Check voltage and diode mode to ground on SCL/SDA lines o9f battery bus.
If both look good, you should try to reball/replace the SMC.

 

[Instafixx]

Very strange - but i just plugged in the chagrer and now u get 8.6V on the PPBUS_G3H nd i get a fan spin.

The fan spin increased gradually.

Installed the board back to the chasis. Switched on.

 

[Instafixx]

Obviously it wont last. What should i do. Should just wait for it to go back dead.

 

[2informaticos]

Try reballing SMC...