Do we have a source for the trimmers as installed in the RF boxes in the R-390A ? Most upsetting to find some of the ceramic discs cracked and I've run out of replacements Values needed .... 3 - 12, 5 - 25 , and 8-50 pf... Ideally I'd like 4 or more of each type, Advice/sources solicited with usual costs . Thanks Pete VK3IZ