Hardware Switch charges but won't power on

[vrepair]

Hi everyone! I signed up here because it seems to be the best place to talk about Switch hardware repairs. I decided to try my hand at fixing a switch after doing a lot of work on laptops and phones, and I'm a little stumped at the moment. Life sure is easier when there are readily available board views and schematics!

The switch I have was apparently liquid damaged and now will not boot. There was a tiny bit of corrosion on the screen ribbon cable, the power/volume button ribbon cable, and the capacitors near the MAX77621 in the lower left corner of the board. I haven't found any capacitors shorted. The switch will not connect to a PC when plugged in with a USB cable. Nothing is displayed on the screen. It will charge the battery at 5V/0.4A, and will negotiate with a usb-c charger up to 15V/0.4A. The current there doesn't seem right to me, but it does charge the battery albeit very slowly. The CPU appears to be doing something as well, as the copper plate on the shield underneath the heat pipe will get warm, but not hot, after applying power for a few minutes.

Any idea where to look? I know the M92T36 and the BQ24193 are the two charging and power related components that often fail, but I haven't seen symptoms quite like these when searching for answers. What are good test points for voltages required for operation?

Thanks in advance!

 

[Ace_]

Since the battery isn't charging properly have you tried a known good battery? the circuitry inside the battery seems to fail a lot in these water damaged switches.

 

[vrepair]

Since the battery isn't charging properly have you tried a known good battery? the circuitry inside the battery seems to fail a lot in these water damaged switches.

I hadn't thought about doing that...good point. Will a working switch boot without a battery connected but while plugged in to a charger? I frequently do that with laptops to isolate problems but not sure if it would work here.

 

[Undwiz]

water damage ? its fried -- thats all to it

 

[Borega]

I hadn't thought about doing that...good point. Will a working switch boot without a battery connected but while plugged in to a charger? I frequently do that with laptops to isolate problems but not sure if it would work here.

No it wont. Its more like a phone in that way.