I’ve been tinkering with a switch won’t power on. Here’s a bit of background before I get into the troubleshooting I’ve done so far:
- This unit had a damaged LCD connector (which I replaced) but I’m sure that was only damaged when someone was trying to see why it wouldn’t power on.
- This unit has an aftermarket battery
- USB-C port doesn’t show any signs of damage (I believe it to be a factory port)
- Unit reads 15v 0.49amp draw with the battery connected. BQ chip gets pretty warm, not entirely sure if that is expected or not.
- M92 reads 3.3v on pin 6
- After disconnecting the charging cable (with the battery still connected) the unit still has power to the M92 chip (like its trying to come to life perhaps?)
- No shorts around BQ, the M92, P13USB, nor the MAX IC below the SOC
- Probably the most interesting fault I could find is that the coil directly to the left of the LCD connector is reading a 0 Ohm short. I probed the caps right next to that coil but they don’t appear to be shorted. Injected 1v at that shorted coil but didn’t notice anything getting hot on the board.
As far as tools go, I have probably everything I need to test this board except an oscilloscope (multimeter, power supply, thermal cam, etc.). I’m still pretty much a novice at diagnosing these issues though so any help you can offer to point me in the right direction would be greatly appreciated.