Thanks for the replies. Yes Mike I'd like to get a copy of the manual, I'll send you a PM. I've just scanned the parts manuals.

Ed the CP51 is online at Unfortunately it's not a pdf you can easily download.

The CP31 I have came from a university lab and seems in very good shape, pretty clean especially for it's age. It was in use up to three months ago and the guy using/selling it offered to help if I ran into trouble. I'd still like to get the operation manual though.

I'd like to look at doing color, but my first task will be reprinting a lot of contact sheets and reorganizing my past, so to speak. My early filing leaves a bit to be desired. First I'll have to reorganize my basement, got some lumber to move and piles of stuff to sort.