820-01814-A Liquid damaged



First off, I am complete novice on these new models so apologies for that.
Now this board had liquid damaged around U1200 and the battery.
Once cleaned some tissue paper, I can't really any corrosion, as if no components were touched by water.
The battery however had stains of liquid on some resistors.

Customer said the MacBook did turn off while running after the liquid spill happened.

I have PPBUS_G3H with a nice 12.6V and obviously a good 19.6V.
One thing that I've noticed is when I plug the charger, I am getting a spike to 0.25amp while being at 5V as if there was a short circuit. (unsure as I don't know the behavior of these 2018 board)
Then it jumps to 19.6V and draw, 0.4amp, then 0.6amp, then 0.12amp, then 0.16amp and back to 0.01amp and dies.
Voltage stays at 19.6V but amperage is at 0V.

CPU_VCore is not pulsing at all.
I've checked some rails around U7800 and I am getting almost all of them with the exception of PPVCCPRIMCORE_PRIM_REG
There is a 47ohms resistance to ground on this rail so that seems fair for a 1.05V rail.

I don't really know where to start looking now. Any hint please?


Staff member
Did you test the board alone on the desk?
You should try ultrasonic bath first.

Without schematic/boardview this could be waste of time after that...


The amperage measurements are done using the board only.

I will definitely try an ultrasonic cleaning but wanted to know if there was something I could check before removing any signs of corrosion if any (even though I couldn't see any on components)

Actually I've just realized it's a 2019 model, not 2018, though that board is very similar to the 820-01041 for which I have brd/schematics.
By the way, using the Thermal cam, the only thing that gets hot when charger is plugged in is the T2 chip, indeed. It goes to 40 degrees and then off.
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I've noticed something weird.
Even though I am getting PPBUS_G3H at 12.6V, when I am measuring the resistance to ground from it, I am getting a short for a second or 2 and then the resistance slowly rises.
But I guess it's my multimeter which is charging the capacitors on that line.
Inversing the probes do it so yeah that's the multimeter.

I've found corrosion on U7370 after removing the heatsink.


I've ordered a U7370 chip from Aliexpress. Still waiting to get it delivered.
The customer gave up on that board and got a new machine...
So I bought the machine for parts. I will test again once I have the chip in stock.