Radio wont turn on unless I Disconnect then Reconnect the battery

Hi Guys,

Really annoying problem with the radio in my E38 (728i – 1998). The radio does not turn on. However, I found- by pure coincidence that if I disconnect the battery- then reconnect it- all works fine (at least for a few hours!). Then I’ll start the car and again the radio just will not turn on. I originally thought that there may be a problem with the radio but due to the fact that “disconnecting & reconnecting the battery” trick works every time Ive tried it, I’m worried that I might spend hundreds of pounds replacing the radio and then find that it’s not that!. Any suggestions on how to fix or at least how to diagnose what the problem is?

Thanks in advance,

Ismail