Cheap shorted device with no service manual, no schematic, and you are not going to spend much time on repair. 1 ohm resistor to simulate short.
Put battery power on device and use fingers to feel what gets hot. If not solved, up the current to 5 volts at 6 amp power supply through USB connector. May burn through short. Check to see what functions on device still work. Device may still do functions you need anyway.
