David Binnewies
Taylor Planetarium, Museum of the Rockies, Bozeman Montana; ammdb@montana.edu
During the Desert Skies conference we saw many new all-dome technologies like Skyvision, Omniscan, and Digistar II. Although these new technologies are very very impressive (and expensive), the majority of visuals in most planetariums are still done using traditional inexpensive carousel slide projectors. Learning to rebuild your worn-out projectors is the most cost effective way to keep them running for many years of service.
For this workshop, I demonstrated how to disassemble and rebuild a Kodak Ektagraphic III slide projector. Almost all problems caused by worn-out projectors can be fixed by replacing the drive and fan belts, and cleaning and lubricating the cam stack assembly. I also pointed out the thermal fuse that sometimes needs replacing, and mentioned some adjustments to correct problems with projectors that do not cycle properly. All the removal, lubrication, and adjustment procedures are shown in the Ektagraphic III shop manual. This manual, and replacement parts can be ordered through a Kodak authorized service center in your area.
Participants in the workshop also offered some helpful advice. Dust is a major cause of projectors wearing out prematurely and is a real problem in some areas. One participant (I'm sorry I do not remember your name) explained how dust can be kept away from projectors by enclosing them a box and pumping in filtered air. The positive air flow keeps dust from entering any openings in the box and away from the projectors. Corrosion of electrical contacts is a problem in other parts of the country. Heat sink grease can be put on contacts which conducts electricity, but keeps air away from the metal. Slides not dropping all the way in the gate can be fixed by lubing with Kodak silicon oil. (This procedure is mentioned in the shop manual.)
The workshop was very well received. Not everyone has the time or mechanical aptitude for rebuilding slide projectors, but if you do, this is a great way for keeping these low-tech workhorses running for years to come.