820-2330 need battery to power up


New member
This board power and work ok and recognize battery in OS X but without battery it will not power up. Is that SMC problem?
No green light. Already tried another jack and adapter.

Only with AC adapter:

ppbus 12.59V
3V42 - Present
ACOK - 3.14
=PP3V3_S5_REG - 3.31V
SMC_ONOFF_L - Tried to short to ground but nothing.
Last edited:


Staff member
What resistance do you measure between pins 1 and 2 of Q6910?

What voltage do you get on pins 5 & 2 of Q6920 with charger plugged in?

What voltage do you get on pin 5 of Q6915 with charger plugged in?

Typically, Q6910/Q6915/U6915 all go bad in tandem. Q6910 internally shorts pin 1 to 2 and dies, which keeps it stuck in "off" mode - as a P channel it won't open unless pin 2(gate) is LOWER in voltage than pin 1(source). This doesn't provide power to the voltage divider at R6917 and R6918 that allows the N channel Q6920 to open. Q6920 needs to open for ADAPTER_SENSE on the charger to talk to SYS_ONEWIRE at the SMC to get a green light.

ADAPTER_SENSE is about 2.9v data line. The entire point of this circuit is to turn off the path between the charger and the SMC(Q6920) if ADAPTER_SENSE voltage is too high because someone is plugging the charger in drunk and messing up the pins or the DC in board dies and has 16v main DC voltage on the ADAPTER_SENSE dataline.