Hum on FM

Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed

Thread Rating:

0 Vote(s) - 0 Average
1
2
3
4
5

Linear Mode

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

Website Find

« Next Oldest | Next Newest »

Thread Closed

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

View a Printable Version

Users browsing this thread: 1 Guest(s)

Recent Posts
Philco 46-480 Electronic Restoration
Mr. Fixr Compared to you I am sooo green behibd the ears...I have about 40 or so sets.morzh — 07:12 PM
48-482 rear panel help
Many thanks to all for the responses! No plastic button "covers" on my radio. Ron, thanks for the chapter on...keithchip — 05:53 PM
Philco 42-345 Restoration/Repair
I am back to working on this radio and managed to get a couple of radio stations to come in. But can someone help me to ...osanders0311 — 01:58 PM
48-482 rear panel help
Hi Kettlechip and welcom to the Phorum. The back panel question is interesting. I have quite a few radios that use pow...MrFixr55 — 08:24 AM
Philco 46-480 Electronic Restoration
Not too much at all! :lol: Sounds like you’re just dabbling into the hobby!jrblasde — 07:56 AM
Philco 46-480 Electronic Restoration
Hi Joseph, Fortunately, Ms. Fixr does not read my computer, or she would warn you against coming to me for sanity ch...MrFixr55 — 07:27 AM
48-482 rear panel help
There's a picture of one of the plastic covers in the following thread: I bought a full set of them in 2012 or so fro...klondike98 — 11:15 PM
Philco 46-480 Electronic Restoration
Good sanity check! You are correct—the first (as in, the most counterclockwise) position is for the push button presets....jrblasde — 11:05 PM
Philco 46-480 Electronic Restoration
Hi Joseph, First, verify that your band selector is in the correct position for what you want to do. I believe tha...MrFixr55 — 10:59 PM
Philco 46-480 Electronic Restoration
Got my replacement signal generator in the mail today! I was able to finish alignment of the IF section. I’ve got some t...jrblasde — 09:58 PM

Who's Online

There are currently 1192 online users. [Complete List]
» 4 Member(s) | 1188 Guest(s)

Login
Username:
Password:	Lost Password?
	Remember me