820-3115 PLT_RESET_L 0V

No-Clean

Member
Clean board, client states that Mac started to have issues starting up, but once was on it worked fine, sometimes it took many tries to get it to start.

C6603 was partially shorted and burned (PP5V_S3) after replacement diode reading is correct but board still has same problem.

Already tried heating up PCH but same problem, tried new SMC and same thing.
 

No-Clean

Member
I forgot you cannot yet read my mind sorry, MLB makes it all the way to 0.9V on PPVCCSA_S0_CPU, I get USB power but no activity, already tried clean bios as well.
 

No-Clean

Member
U7400 gets 3V at pin 47? negative, board gets 0.3V there too.

Do you note a drop pulse at pins 1 & 48? No, when I plug charger it starts at 12V and stays there on both pins.
 

2informaticos

Administrator
Staff member
Sorry for my error.
I was thinking you've got 3V at ALL_SYS_PWRGD; you have 0.3V instead.

Do you get correct voltage at all other big coils (apart of VCORE)?
 

No-Clean

Member
No problem, ALL_SYS_PWRGD is 0.3V also.
L7760 PP1V8_S0 is 0.03V
L7550 is 0V
All other coils get their propper voltage
 

No-Clean

Member
Initially replaced Q7830 and Q7810 and board worked a few times but it failed again, then replaced Q7812 and so far it is still working.
 
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