820-3332 missing PPVCCSA_S0_REG

[dudipupan]

Hi there,

I'm struggeling with an MBP 2012 15" (820-3332). It was running with typical screen blsckout issues so I resoldered U8900 with leaded solder but without success. So I wanted to replace U8900. While removing it, it slipped out the tweezers and landed straight on the components around R8918. I put them back on place carefully and replaced U8900.
Now the Macbook does not turn on anymore. ALL_SYS_PWRGOOD is missing because of missing PPVCCSA_S0_REG.
U7100 gets power and enable voltage.

Thank you and best regards
Dudi

 

[2informaticos]

Do you get RAM voltage at least?
Be sure to resolder all components correctly.
Do not solder components marked as "NOSTUFF".

 

[dudipupan]

Yes I'm getting PP1V5R1V35_S3_MEM and PP0V75_S3_MEM.
I resoldered all components very carefully. Had a donor board where i was able to compare the original positions of the components.
No NOSTUFF components soldered ;-)

 

[2informaticos]

Check U7100 voltages; pins 19, 20, 15, 7.
If all good, change it.
Be sure no short to ground at L7100.

 

[dudipupan]

Pins 19,20,15 and 7 seem to be good (5V, 5V, 3.3V and 0.65V)
Got 8.5 Ohms on L7100.
Changed U7100 but same result.

 

[2informaticos]

Check surrounding components, solders and traces.
Replace R/C7130, just in case.