[SOLVED]PP18V5_DCIN_FUSE missing

[rkrishnan]

I got a 820-3462-A board that had liquid damage with no green light. I tracked down that PP18V5_DCIN_FUSE is missing (it starts at 1.27v and slowly increases til 1.5ish). I can't understand how the 18v gets activated from the charger, is that via the ADAPTER_SENSE line / U6900? I'm using an 85watt charger and the DC-in jack works on the donor board I have.

* Fuse F6905 is shorted just fine.
* R6920 is 47Ohm (as expected)
* R6905 is 10Ohm(as expected)

Resistance PP18V5_DCIN_FUSE to GND starts at 8k and slowly increases until 40k or so

Thanks! Sorry if this is a noob question.

 

[JohnB8812]

Tried known good DC in board?

 

[rkrishnan]

No I don't have another DC in board, but I tried the same dc in board on a donor 820-3462-A and it gives a green light.

EDIT: AHA! Looks like something is pulling the 3.2v from the charger to be 1v. I just need to find whats pulling it down.


EDIT:
I got 18v!! Just for future reference, read this on how the magsafe process works. Make sure you have 68k load resistor otherwise charger wont send out 18k.
http://www.righto.com/2013/06/teardo...f-magsafe.html

Please mark this one as solved.