Mr. Pinball Tip:

Selenium rectifiers (diodes) were used by Genco and others in the 1940s and early 1950s to provide crude DC operating voltage for the game. They appear as a stack of disks (sometimes square) about 3 inches round, with 3 wires running to them. Usually connected to a 'center-tapped' transformer, providing full wave rectification. Beware if you get one of these games from long-term storage. The 'diode' can be weak from disuse, and the machine should first be 'powered-up' through a Variac, or other voltage reducing means. Gradually increase the voltage, starting at about 25, over a period of hours, to reach regular house currant. It helps to gently heat the diode with a hair dryer, but don't over-do it! Don't operate the machine during this; and keep a close watch for sparks/smoke! I've found this successful in keeping the original diode (actually, this setup uses 2, back-to-back; but that's getting picky about names!) Otherwise, it's better to just replace this giant selenium unit with 2 regular diodes. If they do burn, it smells like rotten eggs!

MC

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