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Old 05-20-2013, 01:18 PM
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Reece Reece is offline
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Join Date: Jul 2004
Location: Cleona, PA
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Could be the clock motor. Things to try: disconnect the clock motor. Try jumping a bit more electrolytic across each filter cap. If the first audio tube is not shielded, wrap a piece of foil around it and test clip it to circuit ground. The idea is to try to find out where the hum is entering the system. Sometimes hum is picked up by the first audio tube: try grounding its grid; what happens?
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