I've done a DIY swap of all the caps and the battery on the board for one of these before. it also cured the issues it had as well. The battery is usually part of the problem, definitely worth changing that in addition to caps. I have some of the manuals and service info available here: http://edsawyer.com/lens/cp31/

It doesn't cover board-level repairs but is useful info nonetheless.

I think the cost for all the caps and the battery were something like $20 or less from digikey/mouser/etc.