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 Post subject: Faulty volume control
PostPosted: May Sat 26, 2012 3:07 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2291
Location: Niagara Falls, NY
Hi Friends,
I'm restoring a metal midget Arvin 422 and I'm having problems with the volume control. Hear "click" when I turn it on, radio lights. When I turn off, often I do not hear "click" and radio continues to play. If I "force" knob counterclockwise, SOMETIMES it "clicks" and radio turns off, sometimes it keeps playing. Control has a pin protruding from it that sits in the chassis to keep the control from spinning around. Its there and inserted into the chassis hole, so thats not the problem.
I have sprayed the dickens out of the part but with no further success.
Any suggestions on repair. I have no replacement control at this time.
Thanks so much, Ken

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 Post subject: Re: Faulty volume control
PostPosted: May Sat 26, 2012 3:18 pm 
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Joined: Jan Tue 03, 2012 10:38 pm
Posts: 599
If you can get the spray inside. Get in it with wd 40 you have to get in the back part of the can. The part that has the two power lead taps. And then use a little electro clean or just blow it out good there is a spring loaded switch in there its just sticking

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 Post subject: Re: Faulty volume control
PostPosted: May Sat 26, 2012 4:27 pm 
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Joined: Mar Fri 11, 2011 4:21 pm
Posts: 793
Location: Hunter NY
I had a similar problem with a Zenith. I took the pot apart, cleaned it, and gave it a check on the meter as well as working the on/off mechanism with a chopstick. Everything worked perfectly. But once assembled it was the same old story, the volume worked, but it would only turn off with considerable persuasion, and even that was hit or miss. It turned out the spring that controlled the "V" shaped switching mechanism (at the bottom of the pot), which provided the switching force had lost tension, letting the contact hang on the side of the "contact" dimple instead of snapping it underneath. This accounted for both the lack of a good "click", as well as allowing the radio to continue playing. I disassembled the pot again and removed the spring, but use caution because it is under a considerable amount of tension, and when it let loose I heard the tell tale zing of the little dimpled "top cap" between the spring and the "V" shaped switch ricochet around the shop, never to be seen again. Once removed I elongated the spring, found a replacement for the missing part (the one that flew off when the spring was removed), and carefully reassembled. It worked perfectly.
For a quick test, to see if the contact is hanging up, you could give it a good quick snap into the off position a couple of times (with the radio unplugged so as not to hit the tubes with sudden on/off bursts of current). See if this will give it enough force to get the contacts to click.
Good Luck


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