[SOLVED] 820-3435 Green light only when battery is disconnected

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Sykulski

Member
This is an Air 11" 820-3435

Came in dead with no light in charger.

- When I disconnect the battery green/orange light comes up and all is working fine. (SMC_BC_ACOK = 3.11V)
- When I connect a charged battery no light in charger but runs fine from battery. Not charging off course (SMC_BC_ACOK = ~200mV)
 

larossmann

Administrator
Staff member
PPBUS_G3H is 16 volts instead of 8.5v because of shorted Q7130. The light turns off because if the machine sent 16v to your 8v battery it would explode. Believe it or not PPBUS_G3H can go from 8 to 16 with no system damage, all downstream power rails are designed to adapt and adjust their switching frequency accordingly.

Check it!
 

Sykulski

Member
2informatico: I will take some ISL measurements later

larossmann: PPBUS_G3H is 8.60V on charger and 8.45V on battery (97% charged)

aprendiz: Yes i tried with another battery

I also tried to start the machine from charger with battery disconnected and then plug the battery while running (yeah I know... but I took the chance) and then it continues running, discovers and charges the battery just fine. If I now take out the charger and plug it again then no light and no charging.
 
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