820-02020 : 5V on DV, 20V on charger, no power

dudipupan

Member
Hi,

I got an M1 Macbook (820-02020) with some strange behaviour.
It suffered from liduid damage around UF400, Touchpad connector, LP9000 and CP870.
I removed shorted Cap CL053 and replaced UF400.

Behavior if DC only plugged:
Taking 5.23V, 0.12A (somtimes jumps up to 0.6A for a second).
PPBUS_AON is quickly pulsing to between 0V and 12.3V.
PP3V8AON_PH1-3 stable 3.8V
Most other rails are pulsing.

If I connect the battery I got stable rail voltages and 20V, 0.13A on USB-C.
PP1V8_AWAKE: 1.79V
PP1V8_S2: 1.79V
PP1V2_S2: 1.2V
PP1V25_S2: 2.8V (too high?!)
PP1V8_AON: 1.8V
PP1V2_AWAKE_PLL: 1.2V
PP0V8_AWAKE: 0.8V
PP1V25_AWAKE: 2.8V (also too high).
PP2V5_AWAKE_NAND: 2.6V
PPVDD_PCPU_AWAKE: 0.73V
PPVDD_GPU_AWAKE: 0V
PPVDD_CPU_SRAM_AWAKE: 0.85V
PPVDD_ECPU_AWAKE: 0.73V

I cant get it to DFU mode (even with battery connected). Maybe because of PP1V25_AWAKE too high?
 

dudipupan

Member
Ok, after removing UE501 (there was some corrosion on it I didn't see) the 1V25 rails are normal and I got 20V, 0.22A and stable PPBUS_AON on DC power.
 

2informaticos

Administrator
Staff member
Did you follow all the steps from DFU tutorial?

Try forcing the board in DFU with SV004/5.
Solder RV005 first, if not present.
 

dudipupan

Member
Forcing th board in DFU worked. Maybe the keyboard is defective. But unforunately I can neither restore nor repair. It throws an "No such directory or file (NSPOSIXErrorDomain)" error...
 
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