All plugs in the correct sockets, and playing ok, just can't control them remotely. I have simply replaced a BM6500 with a BM7000 so all din plugs are the same as I have been using for the past 5 years

The datalink signal has some protective diodes to ground and power that could have shorted.
Worth checking.

Martin

D1, 2, 3 and 4 on board 3 I presume, (I'm working from the service manual), I'll check tomorrow, thanks Martin. It's also not retaining any settings or radio presets, I assume the battery on the microprocessor pcb

Battery, most likely.
And a bad battery can cause other problems too.
I would replace the battery first.

Martin

So I can carry in using it while waiting for the new battery can you tell me what type I need, then I won't have to take it apart till it's here.

Forget it, bit of research and it's a CR2450 !

Well this just goes from bad to worse !

Yesterday I plugged in my recent auction win to find it won't talk to the CD etc. and wouldn't retain any settings but at least I listened to music last night.

Today it won't respond to the remote so I cannot use it at all. I will replace the internal battery when it arrives, how much it will resolve, who knows 😔

Stranger and stranger. Despite numerous power on and off yesterday I couldn't get a peep out of the BM7000, with the resulting request for my money back from the auction seller who said it was working, (with no other B&O equipment with which to test it he should have said, lights come on !). Today, power off then on, all has come back. The remote not only works the BM7000 but has now decided to operate the Tape and record decks but still refuses  to operate the CD which is a real pain as this unit needs the remote more than the others.

cmsammy wrote:

The remote not only works the BM7000 but has now decided to operate the Tape and record decks but still refuses to operate the CD which is a real pain as this unit needs the remote more than the others.

Been using it for the past 5 years with a BM6500 with no problem. I can check inside the plug but it seems unlikely that unplugging it a couple of times would break it, especially a factory fit plug.

Progress !

I have replaced the internal battery and this has restored radio presets and amp settings, vol, bal etc. I can also turn it off without loss of remote access.

One fault remains, remotes operate everything except the CD, I've checked the din plug and used contact cleaner in the socket to no avail, seems odd it operates tape and record deck, neither as important as the CD, typical.