silver dip capacitors

[wozzie]

Gday fellas
Im restoring an FT101E ham radio and having trouble sourcing some caps.
Dose any know where i can get 82pf 2kv and 1000pf 2kv silver dip capacitors.
Any help would be much appreciated .
Thanks

[redwire]

I think you have the wrong name for them, they are "silver mica" (although I have no pics of yours).
Used for medium power RF (low dielectric heating) and anywhere you need rock solid tempco. How did yours fail, they are pretty much indestructible.

Cornell Dubilier Mica Capacitors, Standard Dipped might be what you are looking for.
I find them a bit expensive nowadays. Another place to look for them is at surplus dealers or eBay. Above 2kV things become doorknob caps I think.

[stj]

i have head of them failing in really old valve gear - probably related to tarnishing/oxidising if the coating fails.

[redwire]

I checked pics and they look like epoxy housing, so that could crack and moisture get in. The CDE caps are dipped epoxy but seem to stay good for a very long time.

[stj]

if you watch shango video's he shows bad silver caps in tuners a lot.
he uses a military image intensifier to actually show arcing on the caps!

[andrewsawesomr]

Can't you usually replace silver mica capacitors with film capacitors? Or am I wrong about that?

[wozzie]

G'day guys,
Thanks for the replies.
The original cap's haven't failed yet,just heard to many bad stories about the old cap's.
Would like to replace them with the silver dipped mica.
Thanks