Prestigio PMP3970B_DUO, Technical & Service Manual, Page: 8 / 24

connected, try to find out which part is malfunctioning by replacing by turns the mainboard and the
LCD and launching the device.
Bug 3) Starting up crash at the stage of starting up picture.
Malfunction can indicate problems of two aspects:
1.
Firmware of software: caused by a loss of the document package or too much software installed,
the suggestion is to reinstall the firmware.
2. Hardware malfunction: a) check whether the voltage is too low, the adaptor is well connected,
usually caused by low battery or a failure of the battery. b) Motherboard’s damaged, replace the
motherboard.
Bug 4) The battery can’t be charged after starting up . Possible reason:
1. Check whether the battery lines are in good condition and the battery doesn’t have a leakage.
2. Check whether the power supply VCC+3.5v~4.2V of battery is functioning.
Bug 5) USB, HDM, SD cards don’t function.
1. The three connections lead to motherboard directly, so first check if there are any bad contacts or
broken connection.
2. Check if the external device is compatible with the original device.
3. Due to the frequent inserting and pullting out, the solder between the connector and the
motherboard might not be in good condition, re-solder it or renew the connector.
Bug 6) The camera doesn’t work.
1. Check if the camera is activated or there is dust in the lens.
2. Check the hardware, check whether sensor is connected well to the motherboard, replace the
sensor to see if it’s broken, otherwise it is the motherboard bug.
Bug 7) WIFI does not work.
1. Check whether WIFI can be started, please refer to the instruction to get details.
2. Check the hardware, whether the WIFI board and antenna are well connected, check voltage of
WIFI board, crystal oscillator.