04-06-2016, 08:34 PM
Hi Mike and welcome,
http://www.nostalgiaair.org/pagesbymodel...013339.pdf
Well let's try grounding pin 3 of the 7C6. That will tell us if the hum is in the power supply/ audio stages. If it persisted pull the 41 tubes out. If the hum is still pretty loud you've got a problem in the p/s probably filtering. You can also try pulling out each tube except for the 84 and see if the hum drops. Reinstall each tube before removing the next. That will give you a clue as to which stage is problematic.
GLOM
Terry N3GTE
http://www.nostalgiaair.org/pagesbymodel...013339.pdf
Well let's try grounding pin 3 of the 7C6. That will tell us if the hum is in the power supply/ audio stages. If it persisted pull the 41 tubes out. If the hum is still pretty loud you've got a problem in the p/s probably filtering. You can also try pulling out each tube except for the 84 and see if the hum drops. Reinstall each tube before removing the next. That will give you a clue as to which stage is problematic.
GLOM
Terry N3GTE
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