[R-390] No receive below 8 Mc

[Jim M.]

I have found that any mica cap that touches B+ will be suspect. For example the caps across the primaries of RF cans, where the primary is in the plate circuit of a stage. Being exposed to B+ over a lifetime must compromise the dielectrics. And as you probably know, many of these type caps are actually inside the cans, so you have to remove the metal coil covers to replace them.  I recently did a shotgun replacement of all primary caps in my SW 390a and noticed an enormous improvement on all bands. 

Jim N4BE

Sent from my iPad