Pro Camera Servicemore info
710 East Thousand Oaks Boulevard
Thousand Oaks, CA 91360
Sun Plaza Shopping Center
(805) 497-7240
procamera.net
They can fix it. They use to have parts on hand, now they send some repairs out, probably to tocad, but it comes back in time and working well.
Be careful about buying a used worn body because you're trading one problem for another.
You can tell a Contax 645 is worn by removing the finder and listening/feeling the mirror slap. If it's silky smooth and quiet the camera is usually good, if it slaps or makes a hitting noise then it's very worn.
I have 4 bodies, only two repairs ever (one was user issue of a thumb through the shutter) the other was a lens connection issue.
FWIW always travel with the contax prism off the body, as the connectors on the prism to body are a composite material and will crack if slammed around in shipping, (or if you pick the camera up by the prism) which makes for intermittent connection.
(tocad use to sell these connectors at a reasonable price).
The Contax has an electronic interface which is perfect for digital backs, BUT you must have a clean connection from lens to find to back.
Before every project, we don't just clean all the lens and finder connections, we polish them and it will connect for weeks without issue, but you have to maintain this camera to get the most out of it.
Good luck
BC