Press the power on key, the red LED light does not turn on, and the POS does not turn on.
1) The mainboard issue: Measure the voltage of the Pin39 and Pin41 of the wireless Module. The normal voltage of Pin39 is 2.8V. The normal voltage of Pin41 is 1.8V. Check the U11 is soldered well or not. If the U11 is broken, it will lead to the Pin39 and Pin41 has not voltage output.
2) Check the energy the battery is used out or not. Try to charge the battery for some time.
3) Check the power on key