820-3476 Liquid damage does not power on


New member

I'm trying to fix a liquid damaged 820-3476 board.
After the cleaning I got green and orange light on the charger.

U7200 was correded. I changed it.
The board still does not start. The fan does not spin up.

I have:
PPBUS_G3H 12.56V
RSMRST at 3.1V

PP5V_S4 - comes on for a sec
Y5110 oscillates - for a sec. I changed the SMC I thought that's the problem. It wasn't. It does the exact same thing.

When first I connect the adapter I can measure all the voltages for a sec.
So I have CPU VCORE. PP3V3_S0 etc. I got something on every power rail for a sec, but the fan doesn't spin up at all.
I have to reconnect the power adapter every time, if I want to measure those power rails.

Any thoughts?

Thank you!


New member
Yes, The CPU VCORE comes high for a sec. Well, hard to tell what the voltage is on Y1905. I got a very weird wave on the scope.
Multimeter jumps up around 1V for a sec. Hard to tell. I changed Y1905 and U1900 same thing.

I've one more exact same board almost with the same problem, but that one tries to turn on-off (fan does not spin). I just can see on the CPU VCORE it jumps up and down for a sec.