Hi everyone,
I’m working on my first Switch Lite repair, which did not appear to power on or charge when I received it. Based on what I’ve read / seen online, this is usually either an issue with the charge port or the M92 chip.
I’ve stripped it down to the motherboard and done some initial testing:
- Inspected the charge port, seems physically ok
- Tested the fuse just below the charge port, continuity ok
- Checked for short on the test point just below the charge port, no short
- Checked for shorts on all caps around the M92 and BQ chips, no shorts
I then injected 5v from a standard USB charger (not official Switch charger) and probed around for voltages. Interestingly I got ~5v on pin 5 of the M92, and ~4v at the battery positive pin. When I tested the battery out of circuit it registered 0.0v, so totally dead.
Is this suggesting that actually the charging circuit is fine but just the battery is completely dead?
I have a TP4056 battery charge module I could use to try and revive it, apparently some people have reported that this sometimes works.
If a dead battery is not the cause, what else should I be looking at and measuring to determine the culprit?