01-31-2009, 08:39 PM
I have rarely needed to adjust the back of a variable capacitor; if the assembly is turning OK and the rotors are not touching the stators, leave well enough alone. But if you must, you could try the following.
Spray first with WD40 and let sit for a few hours. I also give it a shot of De-Oxit too.
Get a very good box wrench to fit the nut. You could also use a properly fitting nut driver but proceed cautiously. It is easy to break the nuts, they are often fragile, and made of brass. After an intimate relationship with rusting iron and mouse pee for half a century or more, they are reluctant to part.
Make sure the wrench fits the nut very well. Then tap the wrench lightly anti-clockwise with a wood stick or small mallet. Do not over do this. Sometimes a tap or two clockwise followed by a few taps the other way will work. If there is a lot of crud and rust afound the nut, you could try to scrape it away with a scalpel or small knife, followed by more WD-40 or machine oil. Once the nut is a little loosened up, you should be able to re-tention the device by turning the screw. Brute force will not serve you well. Everything must be treated with lubriplate or lithium grease before tightening up. I clean everything up with a little paint thinner with a paper towel underneath to soak up the drippings. Of course don't fire up the set for several hours if not overnight after using flammable solvents, and remember to take the trash rags and towels out of the house right away. That and left (other) hand in the pocket has kept me alive so far.
So far as the front bushing is concerned, I don't have a lot of experience there, but there were sometimes rubber bushings to damp the tuning capacitor so that critical tuning, especially on SW bands, would be possible. Kind of like go/no go mechanical couplings. Others would know more than I about these things. But unless there is a gear or idler of some sort, it's a 1 for 1 deal.
Spray first with WD40 and let sit for a few hours. I also give it a shot of De-Oxit too.
Get a very good box wrench to fit the nut. You could also use a properly fitting nut driver but proceed cautiously. It is easy to break the nuts, they are often fragile, and made of brass. After an intimate relationship with rusting iron and mouse pee for half a century or more, they are reluctant to part.
Make sure the wrench fits the nut very well. Then tap the wrench lightly anti-clockwise with a wood stick or small mallet. Do not over do this. Sometimes a tap or two clockwise followed by a few taps the other way will work. If there is a lot of crud and rust afound the nut, you could try to scrape it away with a scalpel or small knife, followed by more WD-40 or machine oil. Once the nut is a little loosened up, you should be able to re-tention the device by turning the screw. Brute force will not serve you well. Everything must be treated with lubriplate or lithium grease before tightening up. I clean everything up with a little paint thinner with a paper towel underneath to soak up the drippings. Of course don't fire up the set for several hours if not overnight after using flammable solvents, and remember to take the trash rags and towels out of the house right away. That and left (other) hand in the pocket has kept me alive so far.
So far as the front bushing is concerned, I don't have a lot of experience there, but there were sometimes rubber bushings to damp the tuning capacitor so that critical tuning, especially on SW bands, would be possible. Kind of like go/no go mechanical couplings. Others would know more than I about these things. But unless there is a gear or idler of some sort, it's a 1 for 1 deal.
