Hum on FM

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Hum on FM

Eric Adams
Phorum Expert

Posts: 825
Threads: 113
Joined: Aug 2012
City: The Villages State, Province, Country: Florida

09-15-2013, 11:21 AM

Well, here I go again. It looks like the most problems I have are some kind of hum and they're all different.
This one is a Zenith 79H20. After a recap, all tubes tested as well as resistors. AM sounds great. After an alignment FM pulls in many stations. Between stations there is a steady hum. To confuse me even more, when I touch the volume control shaft (using an isolation transformer) the hum gets a bit louder. I've checked all ground connections. Could I have missed a resistor or a mica cap?
This really is a great sounding radio. Any ideas? Icon_confused

:
http://www.nostalgiaair.org/PagesByModel...025312.pdf

Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org

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Messages In This Thread

Hum on FM - by Eric Adams - 09-15-2013, 11:21 AM

RE: Hum on FM - by Mondial - 09-15-2013, 08:42 PM

RE: Hum on FM - by Eric Adams - 09-15-2013, 10:03 PM

RE: Hum on FM - by Eric Adams - 09-16-2013, 12:30 AM

RE: Hum on FM - by Paul Philco322 - 09-17-2013, 08:48 PM

RE: Hum on FM - by Eric Adams - 09-17-2013, 08:59 PM

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