A1534 power cycling

[adrko]

Hey guys

Got A1534(820-00244) that is power cycling.
Takes 19-20V from the charger but cycles between 0A -> 240mA -> 415mA -> 0A

Bought it as broken, for parts. Someone took it apart before, stripped screws, stripped screw holes and metal shavings on the board.
Nosigns of any rework done on it.

Signs of liquid damage, tiny spots of corrosion, darkened caps below U7000(C7016, C7028, C7012, C7017)
C9300 below U3700 looks dark/corroded - it's for PP3V3_S5 -> ground. But its not shorted, nothing is shorted.

I want to ask for opinion before I start looking for replacement caps. No clue if that might be the problem.

I took off and reballed U7000 and U7800 because I noticed signs of liquid being under the chips at some point.

I went through every single power rail.
Only these are not correct values - rest (every single one)just goes to specified value and drops down to zero. Nothing stays on permanently.
PP3V3R2V7_NAND_VCC - 2.8V (3.3V in schematics)
PPVCORE_S0_CPU - 1.32V - 0.74V (1.8V)
PPVCORE_S0_GT - 0.0V (1.8V) (3.9 Ohm - from what I understand CPU rails are always low resistance)
PPVCORE_SUS_PCH - 1V (1.8V)

Thank in advance

 

[2informaticos]

Voltages did not catch nominal value, because of cycling power.
A1534 is the worst machine made by Apple.
Very high-density board, liquid spill is almost letal.
I do not recommend to waste time on it.
CPU and SSD failures are classic problems.

Check if stays on in SMC bypass mode.
PLT_RESET_L pulsing too?

 

[adrko]

Yeah, got it cheaply tho. I'sorry but I don't know what is SMC bypass mode

 

[2informaticos]

Use Google and earn time...

how to smc bypass macbook - Buscar con Google