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moog modular System 55 restoration
Now this is one of very few modules with complex circuits, and double sided PCB. Thru-hole metal platted in 1974! Only serious industry used that. It's the famous 921B Oscillator. It is worth mentioning that only oscillators contained the decent quality rotary switches. After 40 years they were still working very good, and required only slight cleaning.

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© 2013 Roman Sowa
Last revised November 24, 2013