Jim, which one, model, is it? I have one that had dead electronics, I tried and tried to clean the contacts and such but in the end I took all of the electronics out, the boards, and changed the 83V halogen bulb with a 120V halogen bulb of the same color temperature. This head has the three knobs on the front to adjust the color, C,M,Y. I bought a used color analyser so I could figure out the filtering and since I don't do color it works great. The transformer went out in the original configuration and now I don't need a transformer and that archaic 83Volt bulb. I runs it on a Sola CV supply so there is a consistent power supply to the unit. I wired the original fan separately as it has to run until cool after the unit has been used. I need to put it on a spare timer so I don't forget to turn it off though.
If you need to get going sooner than later then an Aristo head works very well on these enlargers.