DRAM 128K system has stopped working

[CheshireNoir]

Thanks someone and Ewan,
OK cleaned the contacts with an ink eraser. Also dropped a bit of Deoxit D5 into the socket, taking care to clean up afterwards.
Still no change so I reflowed the edge connector. (It was a bit gnarly and reflowing with fresh flux can't hurt)
Again, no change.
someone, you confidence in me being able to write anything more complex than some basic BASIC for the 'bee is greatly overgifted :-)
I do seem to remember you posted a Test ROM image in a post somewhere, but b&ggered if I can find it, now I need it :-D

Anyway I am off to demo my Educator 32K to a bunch of Amiga fanatics. Should be a good show!

Cheers everyone, and thanks again.

Chesh