820-00165 No Green Light

[hambook]

Hi all, have an 820-00165 on my bench that won't turn on, has no green light and pulls 42mA from the power supply. I measured PPBUS_G3H as 0.6v and PP3V42_G3H as 0.1v, but I'm not sure what to investigate from here. No super obvious spots of corrosion or gunk anywhere.

 

[2informaticos]

I suppose a leakage problem.
Post DCIN_G3H voltage.
Did you try with lab PSU, or fake charger?

 

[hambook]

DCIN_G3H is 18.5v, this is with a lab PSU and genuine Magsafe

 

[2informaticos]

Check diode mode to ground at L7095 and L7130.
Also check D7012.
Post U7090 voltages.

 

[hambook]

Diode mode at L7130 is 0.159 on either side, but at L7095 it's 0.001 on either side, so this means something is shorting this to ground right?
U7090
Pin 1 - 0.58v
Pin 2 - 0.18v
Pin 3 - 1.18v
Pin 4 - 0.32v
Pin 6 - 17.74v
Pin 8 - 17.74v

 

[2informaticos]

You can use voltage injection method in this case.
Read the forum, many information available about how to do that.

 

[hambook]

Injected 1v, the shorted component pulled just over 2 amps. Felt around the board and found the SMC to be burning hot. Is reflowing worth a shot or should I be replacing the SMC at this point?

 

[2informaticos]

Reflow dead SMC???
It is shorted, change it.

First be sure to get 3.42V on L7095; if R7095 is open/corroded, there can be 7V, or more.

 

[hambook]

SMC changed and board is working! Thanks for the help!