Switch V2 - no charge. Getting trolled!

Nintendo Questions Nintendo Switch
#1

got a strange one here. Switch boots fine and shows charging icon (original nintendo charger) however it actally doesn’t charge and the percentage creeps down when the switch is power on. Switch draws 15V 0.05A. When you put the charger into the USB it doesn’t boot and you need to manually press the On button.

I’ve checked all the caps, replaced the BQ, Fuel guage, M92 and still the same. the problem seems to be that I have 1.2VDC (in Diode mode) and 420K Ohm (I think 420K is ok?) on pins 1 & 24 of the BQ. tracing it back and removing components it only disappears when I remove the M92. I’ve tried a couple of M92’s (all pins on the M92 show as in spec in diode mode). Nothing is showing hot in a thermal camera and I’m thinking that something is dragging the M92 down when it comes to pins 1 & 24 on the BQ.
USB C has been swapped as well and a breakout board shows the pins in continuity to the right places. This one has got me scratching my head.

Also Pins 4 & 6 on the M92 show 0.9 & 0.2VDC and swap over when the charger is switched around but it still doesn’t boot unless I press the power button. Also tried different batteries and still the same.

Any ideas?

#2

Maybe a Problem with the fuel gauge? (MAX17050 IC)?

#3

swapped it a couple of times and all the Caps are within spec around it

#4

I would check readings on the pins at the usb c, continuity may be fine, but if say the data lines had been shorted to 5v it could have damaged that part of the SOC.

#5

What voltage do you get on 2R2 coil and PIN1/24 BQ
FYI, diode reading 1.2+ is normal on v2 board BQ PIN1/PIN24

#6

just dug out another HAD board and you are correct. the BQ has 1.1VDC on pins 1 & 24. Back to the draeing board for this one. I’ll check out the diode readings on the USB as a starting point