820-3023-A ALL_SYS_PWRGD missing


Hallo everybody,

I got another problem with a MacbookAir (820-3032-A).
Is seems to get in S0 state (taking 300 mA) but not powering on. I noticed that ALL_SYS_PWRGD is missing so i checked the needed rails and found PP1V05_S0 beeing low (0.22V).
So I checked where PP1V05_S0 (resp. PPCPUVCCIO_S0_REG) is created and found Q7630.
I coudl measure the fallowing voltages for Q7630:
Pin Voltage
1/2 8.4
3 0.28
4 0.26
5 0
6/7/8 0.22

Can anybody help me with some hints for further steps?

Thank you and best regards


Staff member
Stop to check Gate voltage on any MOSFET from a buck-converter.
You must check U7600 voltages, which controls Q7630; pins 3, 13, 14.

Do you get voltage at L7330 and L7720?


Thank you for your reply and your advice!

I checked U7600:

Pin 3: 3.3V
Pin 13: 5.18V
Pin 14: 5.17V

Seems to be normal? Has enable Signal and gets Voltage.

I get 1.81V at L7720 and 1.52V at L7330.