Air can freeze spray question for poly caps

[sonicmojo]

Hey guys,

I'm refurbishing a '74 Ampeg V-4B bass head and I'm getting a lot of static when I cold spray ANY of the blue Paktron molded poly caps. I know this can be a sign of trouble but can these type caps react to cold like this normally? I am curious what other people are finding when testing with the cold spray. Also, is it possible to damage these kind of caps this way by subjecting them to spray like this? I'm going pretty light with the spray. I don't want to crack the casing by deep freezing them.

Thanks!

[Stevem]

With all too many of there era Ampegs I would just replace any of the multi colored ( valvue) caps as on many of then the outer shell is cracked , or soon to be such!

[Structo]

Not sure but we used to use the cold spray on semiconductors to test for thermal issues.

A sealed cap is pretty tight, but maybe not suitable for minus 200.

[Leo_Gnardo]

Ampegs of that era often have aqua-blue coated film caps, or "tropical fish", sometimes others, that are candidates for replacement. I use Mallory 150, follow suit and you won't be sorry. Also those huge 0.33 uF caps carrying signal to the output tube grids, wayy big. Not much point in expecting output transformers to transmit subsonic signals. You can do with 0.1 and that's plenty.

[sonicmojo]

Thanks, I'm just going to replace all of them. The .33 are hard to find. Thanks for the tip.