You should reset your system when the device stops responding or appears to be "frozen" or "locked up＂.
To reset your system, press the Reset button on your device.
If your device still does not respond after being reset, you can use the following steps to clear the memory, and reset the system settings to factory defaults.
Disconnect all cables, including the AC Adaptor, from your device.
Use the stylus pen or your finger to slide the ON/OFF switch to the OFF position
Wait for 1 minute and then slide the switch back to the ON position.
Your device will automatically turn on and the Main screen will appear.

> Make sure the power switch is already in ON position
> The remaining battery power may be too low to run your device.
> Connect the AC/DCadapter to your device to make the charge.

If the screen does not respond even after you press the power button, try the following in order until the problem is solved:
> Connect the AC/DC adapter to your device;
>Reset your system.
If the screen responds slowly
>Make sure that your device is not running out of battery power. 
If the screen freezes
>Reset your system.
If the screen is hard to read
>Make sure that the power is enough
>Make sure that the backlight of the display is on
>Move to a location with more light
>If the problem still exists, reset your system.
If inaccurate response to stylus pen taps or finger tip
>Recalibrate the touch screen.

> Make sure that your device and your computer are both turned on before trying to establish a connection.
> Make sure that the cable is securely plugged into the USB port on your computer and on the device. Connect the USB cable directly to your computer
> Reset your device before connecting the cable. Always disconnect your device before you restart your computer.

When there are no valid signals available, consider the following:
> Make sure that the GPS antenna is adjusted to the horizontal position (parallel to the ground) and it has a clear view of the sky.
> Note that the GPS reception can be affected by:
- Bad weather.
- Dense overhead obstacles (e.g. trees and tall buildings).
- Other wireless device in the car.
- Reflective car window tint.

If  the earphone is in the earphone jack, the speaker will be no voice, take  the earphone from the unit, then the voice out comes Rotate the Volume Switch to the + position and upwards
Check the Sound Settings on your System ,make sure your voice setting is correct and the voice volume is big or not

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