820-00923 - PPBus 0.5v

[Palhano]

The client tried to replace the battery and reassembled everything incorrectly. The Mac stopped turning on.

The CB701 was burnt. I removed it, and the line is free of short circuits. But the PPBus is still missing.

I removed the F7000 and checked the line on the C7050; it had 0.5V. I replaced the U7000 with a new one (Chinese), and the C7050 had 10V, but it wouldn't turn on.

Then I replaced it again with two other ones I removed from the board; both were at 0.5V.

I checked the resistors near the U7000s, all OK.

P_IN - 20V
AUX_DET - 4.1V
SMC_RST_IN - 0
VDDA - 5V
VDDP - 5V
EN_MVR - 5V
SMC_RST* - 3.4V
AUX_OK - 3.4V
AMON - 0
BMON - 0

Any tips?

 

[2informaticos]

What is actual C7050 voltage, with F7000 removed?
If still 0V, replace Q7030/40.
Also check R/C7030/40 and their traces.

 

[Palhano]

The C7050 is still 0.5v. I replaced the Q7030/40 and nothing changed!

I checked the R/C7030/40, everything was perfect.

 

[2informaticos]

Check resistance (ohm scale) over C7020/23.
Also check if board turns on in SMC bypass mode.
Be sure to use 61/87W charger.

 

[Palhano]

3.4 ohms on both C7020/23
SMC bypass mode doesn't turn on. The meter stays at 5.1V, turns off, and returns to 20V, without turning on.
I'm using an original 87W charger. I also tried a parallel charger.

 

[2informaticos]

Check SMC_RESET_L and SMC_ONOFF_L voltages.

 

[Palhano]

both lines with 3.4v

 

[2informaticos]

Check diode mode to ground on U7000's SCL/SDA lines.

 

[Palhano]

Shorted SDA line (diode mode 0.007).
I removed the u7000, it's not the problem. Can I envy the voltage?

 

[Palhano]

It was the D6950 shorting on the SDA line. I replaced it, the short went away, and I have 12V on the C7050. I put the F7000 back in, and the board is working.

Thank you so much! Always a lifesaver!