I've just acquired a Durst M370 color enlarger that's probably been unused and stored for many years. The cyan, magenta and yellow dials turn but don't do anything to the white light. Anyone know how they work, what might be wrong and how to access the mechanisms?
The color enlargers that I've used had the filters mounted in spring-loader tracks and the dial shafts had cams that lowered or raised the filters into the light path. If the enlarger has been unused for too long, its possible the filters are frozen in their tracks. You would have to find the access panel on the head that allows you to service them. This could be behind a flat panel screwed on the head. Another possibility, most enlargers had a mechanism,usually a lever, where you could move the filters out of the light path to double check the white light focus. You then reversed the lever to drop the filters back to their preset adjustments. If that enlarger has such a lever, then it may be frozen in the up position.
There is a small lever / dial on a side of the Durst head that disengages the filters and shows pure white light. I believe that on M370 it is on the left side, but I am not 100% sure (it is on right hand side of my M670). Try turning it and see if the light changes.
I found the manual at jollinger.com http://www.jollinger.com.