Albert: Welcome to ECN, and thanks for the link you posted. That sure brings back some memories for me! I used to work as a theater projectionist, and trained others to do this work. One of the hardest things I ever attempted was to teach them to draw the carbons apart to extinguish the arc BEFORE opening the arc switch on the projector - the switch sparks and arcs so much less that way [Linked Image](read "longer switch life"). I left the business just before the advent of xenon lamps and platter systems, so I spent a great deal of time trimming carbons, pre-cooking hundreds or thousands of them in the lamphouses just prior to use, changing brushes in the generators, testing and replacing amplifier tubes, performing mechanical maintenance on two glorious vintage Brenkert projectors with "Enarc" lamps, and other tasks far too numerous to mention.

In many ways, I really miss those days [Linked Image].

Mike (mamills)