I have a NAVMAN PIN570,

Question

I have a NAVMAN PIN570, this machine was replaced/repaired last year after the adaptor plug separated from the unit.It has been working fine for approx 12 months, but now the screen does not light up.I have checked the settings, they are selected to 'bright'.Do you have any ideas or do I have to send it back for repairs again?RgdsBARRY.