Radio Cassette fault

[aniraf]

I bought a replacement Rover radio/cassette CR213X for my facelift 75. The car was originally fitted with a radio/cd player, but as I wanted to play all my old 'fluff Freeman' Pick of the Pops tapes, I fitted a CR213X unit, which worked fine till a few months ago, when the tape player started to play up. This replacement I bought keeps beeping every few seconds as if it is trying to tune into a station, even though it is tuned in. Any ideas