Faults: does boot to stage two, but the switch does not charge.
- 15V 0.027A on a usb meter.
- Port fuse is good.
- No shorts around the MT92 chip.
- Tested with the original battery and a new battery. Both batteries have a voltage of 3.9-4.0V.
Observations around BQ24193:
- VSYS capacitor was shorted, removed cap but short remained. Removed BQ24193 and short was gone.
- Replaced VSYS capacitor and BQ24193.
The BQ24193 chip was slighly wonky so I removed and resoldered
BQ24193 voltages are:
pin1 - 15v
pin2 - 0V
pin3 - 0V
pin4 - 0.004V
The switch is turning on and showing the charging symbol, but the battery percentage is DECREASING. In about 3 hours on charge the battery has gone from 69% to 58%.
Usb meter still shows: 15V 0.027A.
I have attached a screenshot showing diode mode readings. The left side shows readings from a switch that charges (15V 0.45A) and the right side shows readings from the switch that doesn’t charge.
FYI: the readings were added to copies of the same image.