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38-7 audio "buzz"
#1

I finally pulled a 38-7 table model off the shelf I purchased a while back and recapped it and found a bad 6K5 that was making all sorts of hisses and squeals in the audio. Replaced the offending tube and the radio works well except for a buzz in the audio which sounds much like an unshielded audio cable in other equipment. While it isn't extremely offensive, I know it's there and don't recall my 38-7 console having the same issue. Unfortunately I have the console in the garage awaiting warmer weather for refinishing behind other consoles. The 'buzz' varies with the volume control and does diminish although not completely when I connect the chassis to earth ground. At first I thought it was induced noise because of incorrect lead dressing but moving some of the wiring around doesn't seem to change it. I did find by accident that if I put something metallic (IE screwdriver, needle nose pliers) in the area behind the volume control most notably by coupling cap 28 the buzzing increases. It almost seems that there is some sort of field being generated in that area and being picked up by the coupling caps. All of the caps used were new 'orange drop' type and even tried changing cap 28 with a yellow film type to no avail. Removed the wire from the volume pot going up to the tuning shorting switch but no change there. Has anyone run into this before? TIA


Messages In This Thread
38-7 audio "buzz" - by TonyJSenior - 04-21-2008, 03:44 PM
[No subject] - by justlrnin - 04-21-2008, 05:38 PM
[No subject] - by TonyJSenior - 04-21-2008, 06:40 PM
[No subject] - by Chuck Schwark - 04-21-2008, 09:27 PM
[No subject] - by Texasrocker - 04-21-2008, 11:06 PM
[No subject] - by Chuck Schwark - 04-21-2008, 11:10 PM
[No subject] - by TonyJSenior - 04-21-2008, 11:21 PM
[No subject] - by Chuck Schwark - 04-21-2008, 11:28 PM
[No subject] - by Texasrocker - 04-21-2008, 11:32 PM
[No subject] - by gary rabbitt - 04-26-2008, 10:24 PM
[No subject] - by exray - 04-27-2008, 01:14 AM



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