Zenith MJ1035 volume pot question

[Ampico-kid]

I guess my first question would be....what is it about the volume control itself that would lead you to believe it's defective?

The fact that the volume is low with the control turned up all the way would most likely have nothing to do with the control. And...the fact that you've got a dual control makes the probability of BOTH pots being defective pretty unlikely.

I think you might be barking up the wrong tree.

Try connecting the wiper (center terminal of the volume control) to the signal source (the third leg of the control that you're rotating the wiper toward to increase the volume) and see if you get your full volume. If so...then the control probably is defective (as unlikely as that would seem). If the volume is still low, the control is fine and you've got trouble somewhere else.

Bob

[Jeffhs]

Originally Posted by Ampico-kid

I guess my first question would be....what is it about the volume control itself that would lead you to believe it's defective?

The fact that the volume is low with the control turned up all the way would most likely have nothing to do with the control. And...the fact that you've got a dual control makes the probability of BOTH pots being defective pretty unlikely.

I think you might be barking up the wrong tree.

Try connecting the wiper (center terminal of the volume control) to the signal source (the third leg of the control that you're rotating the wiper toward to increase the volume) and see if you get your full volume. If so...then the control probably is defective (as unlikely as that would seem). If the volume is still low, the control is fine and you've got trouble somewhere else.

Bob

I suspect the volume control is bad because it, and the tone control, were extremely loose when I got the radio from an AK member in Arizona well over a year ago. When I first looked at the control, the rear half of the unit was separated from the front; in fact, the carbon track for the rear pot had separated from the wiper and was (still is) hanging loose under the chassis. At first I was able to get full volume by gently pulling outward on the outer shaft of the control, but even that doesn't work now. I am, however, still able to hear some audio from FM stations, but as I mentioned in my previous post, the sound is so weak I can barely hear it over a hum that is perhaps 50 times louder than the stations I'm trying to hear. I realize the hum is due to a bad filter capacitor, but that's another problem I don't quite know how to deal with; that is, I could replace a defective cap, even a multi-section can-type electrolytic such as is in this radio, but the problem is that there is a bunch of wiring and components directly in front of the capacitor's terminals. Seems to me I would have to disconnect every one of those wires, components and such before I could even begin to think about replacing the cap. I can't for the life of me imagine why Zenith put the filter in this way, with so much in front of the terminals; there is plenty of room under the chassis, so those other parts could have been spread out a lot more than they are. Hmmm.

[Ampico-kid]

Take a look at the "Play Things of the Past" website.

http://www.oldradioparts.com/

Gary has a ton of potentiometers both NOS and old parts. I spotted at least one that sounded good for your purposes:

1487-621 CLARO AD47-Z 2 MEG DUAL POT,1 SHAFT, AUDIO 1 $8.00

Once on the site if you choose to have the pots listed by NUMERICAL RESISTANCE VALUE you'll see a long list of 2 meg pots. Depending on the shaft configuration you might find something there.

As for the filter can access...I'm afraid you're on your own with that one. It's a problem every repair technician and restorer has grappled with from day one. There is no easy solution. Sometimes just moving the wires and components out of the way is sufficient to gain access. Sometimes as you say, the parts and pieces in the way have to be removed. There is no dead set rule of thumb to apply here. Common sense, enginuity and patience are the key to a successful job.

Good luck.
Bob

[Findm-Keepm]

What's the Zenith part number? It'll start with "63-"

I and a few others here on VK have deep Zenith parts stashes. Doug (drh4683) also has some Zenith stuff.

Cheers,