vauxhall blaupunkt 2003 radio cassette?

Hi
the radio in my vauxhall combo (blaupunkt 2003) is giving me a headache.
I cannot hear it most of the time.
When the volume is turned up fully I can just about hear it very faintly if I put my ear agaist one of the speakers. Then suddenly it works normally for a short period of time and the goes quiet again for no apparent reason.
Yesterday I had it playing normally and switched off ignition, and this morning switched it on again and nothing, which makes me think its not a loose connection as the van did not move. But what do I know???!!!
It always displays the station name etc. when i turn it on.
I cannot get any sound from cassette player either.
Is this a common problem? The radios are cheap on eBay so maybe I should try another unit?
Regards
Berkeleyhunt