Hi all trying to put original radio R770 back in my freelander, I'm entering code OK and radio works , my problem is radio does not remember its code and I have to keep putting code back in. I had to buy clock read out because other did not work that's OK but noticed centre of back of the clock looks as if its missing some kind of plug in. Now wondering if it should have some kind of battery for memory, can you advise me on this problem. Bill.