As far as I'm aware there is no such repository, and doubt that even the B&O archive has copies of the software images. There are a couple of potential problems:

1. The single-chip controllers are mostly mask programmed and it's not possible to read the ROM memory from them.
2. There are no pin-compatible controllers with eeprom or flash memory available in most cases.

The Beocenter 7700 uses a Mostek 3870 controller (same as Beomaster 6000) which was not available in an EPROM version, but was available as a bond-out with a piggyback board where an EPROM (2716) could be mounted. I have one of these, but without the software image it's not really of much use for these purposes. I don't know if any lab samples or pre-production samples were produced with the piggyback chip. I have heard of someone developing a replacement chip for a Beomaster 8000 using a completely different microchip (PIC, perhaps) on a small circuit board, writing a program from scratch. Someone else was planning the same for a Beomaster 6000 but don't know if that ever came to fruition. The more usual option is to take a chip from a product which has died of other causes than a SCC failure.

Thanks very much for the reply - great details in there.

Although creating a replacement from scratch is really appealing to me, it a hell of a lot of work.  For me the hardest part would be reverse engineering the requirements.  Even so I'm tempted to see how far I can get with something like a BBC microbit and a Heath-Robinson DIL adaptor.

Cheers

Steve

Actually somebody has done some cloning of the old Bang & Olufsen Eproms for repair, backup, replacement:

https://github.com/theretrobristolian/B-O-Software

https://www.youtube.com/watch?v=g9AHP49MFSs

Fantastic - that's worth knowing!

Thank you!

The service manual is an invaluable aid in reverse engineering the requirements, and most of it could be done using that.

Also there may be some information to be found at

I agree with artig that the service manual is a great resource for fitting an alternative CPU.

I did a project some time ago replacing the CPU in a Beomaster 6000 Type 2253(?). The project was Arduino based. It was a fun project for me, but I really like doing this kind of thing.

An alternative to re-CPUing is to buy a parts machine that has a good CPU, but is in very poor cosmetic condition. Also check with Danish Sound Parts. They might have what you need. This may be the most cost effective solution, especially if you consider shipping for any parts machines.

Glitch