Q:
Few days ago I noticed that the battery of the tuner is no longer charging.
I took the battery out and tested with multimeter, its showing 0V. I bought a replacement battery and during replacement I noticed that both pins of the battery connector have continuity to ground. When I use the tuner connected via USB there is something getting hot on the front left side (where power switch is).
Do you have schematics or something I can use to troubleshoot and see where there might be an issue?
A:
Are you using a fast charging adapter?
If the + and - pins on the battery are short-circuited, it's likely that the battery chip TP5400 on the back of the PCB is short-circuited. Simply replace the TP5400.
Check if the TP5400 has any breakdown. There will be a small hole on the surface, about 0.5mm in diameter.
Q:
Hello, thank you for the quick response.
Yes it was the TP5400, I have ordered replacement. I was mostly charging the tuner from my battery box which has a 5V USB plug. No idea what caused the failure.
A:
It should be that the current is too large during charging, causing the TP5400 to overheat and burn. The TP5400 can support a maximum charging speed of 1A. By default, I use a 1.5K current limiting resistor, and the TP5400 current is limited to about 0.8A. You can replace the 1.5K with a 2K resistor to limit the TP5400 current to a lower level, so that it will not overheat and be damaged.