Christ, when I was dealing with specialist hardware in 2001 that used Psion IIIs we were having to raid eBay for spare serial leads etc... even then!
Psion were just about going and still supplying rom cards direct. They actually sent us one of those USB DAB radios we bought so many. It was as dreadful as all the reviews said, but fair enough, innovative at a time when dedicated sets were still £400ish.
ATI 6000 ?
Isn't this from back in the days when Michael Barrymore was a TV star & the Ford Sierra was a best selling car ?
I'd advise you "to let your fingers do the walking" & reach for the yellow pages & look for new one