When I first got this radio it was my impression that it had been gutted. I now find out that this is most definitely not the case. In fact, only a very few capacitors even need to be replaced.
NOTE: Never be too proud to admit to what you don't know! When in doubt... ASK!
Let me tell you I have found the most knowledgeable group of folks that you would ever want to know over on the Antique Radio Forums. Let me tell you these folks have already pulled my butt out of the fire on a couple of occasions. If your a newbie or an old crow like me who's forgotten everything he learned, this is the group you should be chatting with.
In going through the caps and making a list of what I want to replace, I found about 6 or 7 little black plastic parts with leads that I had never seen before. I checked the schematic and found that they were non-polarized capacitors.
Now I know from reading The ABC's of Capacitors over on Just Radios.com that you don't replace Mica capacitors, but the only Mica's I had ever seen were those square brown jobs with color dots for values. These were black plastic diamond shape critters with esoteric codes that Dan Brown could write a novel about.
So what did I do? I asked!! And a darn good thing I did too.
Turns out they are mica capacitors which should be checked for leakage but beyond that should be just fine. What's more, they are part of the RF circuit (which I am told is very sensitive on this particular type of radio) and so much as changing the length of the leads can cause real problems with alignment and performance. In other words... HANDS OFF.
I see though that it would be a wise idea to either buy or build a good ESR Capacitor analyzer for in-circuit testing, leakage testing etc.
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