Condenser Color Codes (again!)

[Winky Dink]

Yeah, I'm tired of questions on reading color codes, but I'm going to post this anyway.
I have five 3-dot mica condensers. After a day of studying, researching, fasting, and meditating; I can't figure out why the color dots don't correlate with the values on the schematic and the parts list. I took out a couple of the condensers, put them on the multimeter, and got the same values as the schematic.

Here are four of the condensers with the values from the schematic:



(HINT: If you apply the "1st digit - 2nd digit - multiplier" rule, then one of these caps is 61 billion picofarads.)

If there's a simple answer to this I'm going to feel really stupid, but that would just be status quo for me. So, guys, what am I missing?

Thanks.

[Reece]

Me too. Are these all in the same radio? Possibly special code for the mfr? There was some proprietary stuff in the thirties.

[Winky Dink]

All in a Philco 645, ~1936. All appear to be unmolested original components--Aerovox and Cornell-Dubilier. I've seen some unique manufacturer resistor codes from Wells-Gardener in the earlier 1930's, but this is baffling. In any case, I'll plan to check all the values and leave them alone if they're consistent with the Philco specs. Thanks, at least, for confirming my sanity.

[bandersen]

Are there any dots or markings on the other side of the caps ?

[Winky Dink]

Sorry to reply so late, but I've been submerged in Naval Jelly for a week. No markings on the back of these caps except brand names. Thanks.

[Winky Dink]

I finally thought to look at the Philco parts value charts which I had downloaded last year from Philco Repair Bench. Indeed, the mica condensers pictured above agree with Philco's older, unique/non-RMA coding.

Example:



It appears that in the mid-thirties they were transitioning to RMA, but had only applied it to newly developed components at first. So in this set, all the resistors are RMA, but the mica molded caps have Philco's old codes.

Now I can sleep at night.