GPS will not turn on

Hello

A spot of bother with my GPS.

A few times it will not turn on, usually after I have removed the batteries and replaced them with recharged batteries.  The only way I can get the unit to turn on again is to connect to base-map, then disconnect the unit from the computer, or connect to mains power and then turn the unit on and off.  After doing this the unit will once again turn on in batterry mode

Does anyone know of this is known problem ?

Unfortunately  the warranty has just expired.

Thanks, Iain