Denon UD-M30/DRR-M30 problem

I've recently moved house, and the DRR-M30 cassette deck will no
longer 'talk to' the UD-M30 CD tuner/amp.

I can play/record with the system connector disconnected, and the
UD-M30 set to AUX, but the remote then does not operate the DRR-M30.

If I reconnect the system connector and set the UD-M30 to TAPE, the
deck plays, but nothing comes through, even though the remote will
operate the deck.

I'm confused! Any suggestions gratefully received.

TVMIA

David Chamberlin
Cambridge