G4GYS

RENOVATING TUNING CAPACITORS

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Rinse the capacitor under a running tap to remove all soap.

 
Place on a window sill in the sun, or on a radiator to dry.

 
Now to deal with the 3/8 spindle. Not an engineer? Here is a DIY solution. Drill through the centre hole of a furniture corner block 1/4 inch dia. Then drill halfway through 3/8 inch dia. Cut the block through as shown. File a bit more off the cut faces if necessary.


Clamp the block onto the capacitor shaft with a short length of 1/4 inch spindle as shown. Apply a tiny drop of oil to the bearings. Finally, if you have the equipment, check the insulation of each gang to 500vdc. Check for good continuity between each set of moving vanes and the framework. As I said at the beginning, this is a poor example, still rusty but clean and very usable. By the way, the date stamped on the front plate is 16 Nov 1942. This paticular example was given to a friend who used it for the tuning capacitor in a Z match which he sometimes runs at 200 watts!