[Heathkit] Screen bypass caps (was DX-100B on Phone - bad audio distortion /oscillation)

[Rick Poole]

Received in private email:

 >>>>>
>Silver micas capacitors, specially the postage stamp variety, are 
>not immune to silver migration, which is what happens when there is 
>a constant DC high voltage across them but not when there is AC with 
>no DC bias on them.
<<<<<

This is from the grid to ground, so it'd have a more or less constant 
-70+/- volts on them and some low-level AC.

But, wouldn't silver migration cause the cap to short rather than open>

 >>>>>
>That the oscillation stopped with the scope probe's presence is a 
>sure indicator of neutralization issues.
<<<<<

Well, so much for the myth that DX-100's don't need to be 
neutralized, I guess.  Note, however, that everything I have done 
since day one on this thing has been on 80 meters.  Neutralization 
problems on 80 meters?  Really?  Seems like a stretch...

Rick WA1RKT