[SOLVED]820-3115 Working but partial short on PP5V_S3

[phuketmymac]

Hi,

We have that MacBook Pro 13" 2012 which came in as the customer was complaining about a slow Mac.
As usual on these machines, I did blame first the SATA cable but it was fine.
Drive did test fine too...

Opening the case we could clearly see a blown capacitor (C6603)
Voltage drop to ground on PP5V_S3 is 0.1V compared to 0.4V on a know good working board.

So sensor issue in the end...

We did remove the blown capacitor and cleanup the PCB which has been damaged since the capacitor was stuck on the ground side.
To me it doesn't seem to be a short in the PCB but I could be wrong.

I also did remove U7200, C6601, C6608, C6607 and the power amp U6610 and U6620 but no cigar.

I did then inject 3V on that line and couldn't find any component overheating.
Same with 5V...

Anyone already had that issued could give some hint?

 

[dukefawks]

So what is the issue now? Is it still slow? Any errors in ASD?

 

[phuketmymac]

Well I haven't re-solder the components I did remove yet. I am trying to solve the partial short first.

Are you saying that the partial short is not the cause of the problem?

 

[dukefawks]

I have no idea. First run ASD and see if there are sensor errors.

 

[phuketmymac]

Well I did put back every part into places and for some reasons the short was gone.
I just can't explain it. However funny thing is I've tried to measure the voltage drop to ground on another board and it was also .1V on this rail...

Anyway, solved!