There are transit screws in the unit, but it wouldn't have easily gone in without them being removed - it is of course possible that the person who fitted it was a muppet though
Also, ensure you have a proper aerial plugged in, many just install a bit of cheapo wire out the back of the unit and call it a day - not good enough! To get a decent reception, especially when the aerials hidden under the dash, you will need a decent aerial... which is a joke in itself as they're only a tenner!
I would also guess the angle of the unit may be wrong.. if it's too severe then it won't play properly... check this against the mounting instructions - it will give a mounting angle range that is acceptable.
Failing that, don't hesitate to give me a call, 08448 11 22 90, and press 3 for technical support, If I'm busy just leave a msg and I'll get back to you.
Cheers,
Mike
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