01-27-2010, 09:06 PM
On a typical 30s-40s variable capacitor the primary electrical contact is is a little springy fork looking thing that fits around the movable shaft, usually in the center. That's the main one although there is some degree of electrical contact in the front bearings and at the rear pivot point. There are numerous variations but generally those are the points that want to be cleaned and lubed. The bearings require something thicker for long term lubing...the springy thing just wants to be clean with a light lube.
The plates don't need anything unless they are visibly nasty or corroded. In fact any "cleaner" that leaves behind a residue may affect the capacitance value. Bottom line is that the tuning cap should be clean and the moving contacts lubed for smooth and noiseless operation.
One piece that I'm anal about is the little Bakelite or phenolic strip that isolates the stator plates from the frame. Crud=leakage and with these caps often mounted 'vertically' the crud settles on the inner side of that bottom insulator.
The plates don't need anything unless they are visibly nasty or corroded. In fact any "cleaner" that leaves behind a residue may affect the capacitance value. Bottom line is that the tuning cap should be clean and the moving contacts lubed for smooth and noiseless operation.
One piece that I'm anal about is the little Bakelite or phenolic strip that isolates the stator plates from the frame. Crud=leakage and with these caps often mounted 'vertically' the crud settles on the inner side of that bottom insulator.
