Annoying charging IC issue - VCONN 0.9V, no shorted caps, 1.9V on M92T36 pins 5+6

[ksparw]

Hey everyone,
I recently left my Switch on the shelf in sleep mode for about 2 months. I came back to boot it into RCM, and Hekate stated the battery was at 0%, then promptly shut off. Unfortunately, after over 48hrs of charging, including with two different OEM chargers, the battery voltage has not changed - stuck at 2.9V. I started buzzing around the charging ICs and USB port, and I haven’t been able to find any shorted caps, however I did find a few anomalies.

-Pin 5 (VCCIN) and pin 6 (VSVR) of M92 are reading 1.9V on their capacitors, should be around 3.3V.
-Pin 36 (VCONN_IN, aka USB-C power input) reading 0.9V on its capacitor

So, I’m not sure where the issue lies, but I feel like it’s somewhere before the M92. For reference, the USB-C port fuse is reading 5.29V from my OEM charger.

[mightyjebus]

There is some logic circuits inside the battery which might be stopping it from charging as the detected voltage inside the battery is being seen as too low and being cut-off from charging as a safety feature.

Do you have another battery to try?

If not you can try what I did on this thread: search for “recovering-bad-switch-batteries”

One other thing I have observed is if I put a “good” battery into the switch it will work fine then if I connect up the old battery that wouldn’t charge it would start to charge. It’s almost like the good battery clears a flag inside the switch and allows batteries to be charged.

[ksparw]

Unfortunately I don’t, but I have ordered a few Li-ion charging boards to try those.

[FXDX]

Maybe this can help you…Nintendo Switch Voltage Diagram