I have a Leitz Prado 600 2-1/4" X 2-1/4" projector and a Leitz Prado 250 35mm slide projector. The "600" is a 220 volt machine. Has anyone converted one of these to 120 volt operation? Mine is the older art deco looking version. I seldom use it because it is a pain to carry around a step-up transformer. The "600" projects excellent images.