[Ron Ramirez]

I looked at that Nostalgia Air schematic and wondered if what Rider's calls "C7" was the capacitor in question.

The official Philco schematic in the 1946-47 Home Radio Yearbook numbers this part as C402, and the parts list gives this part number as 60-10105407. It is marked with an asterisk (*), and a note included with the parts list states as follows:

NOTE: Parts marked with an asterisk (*) are general replacement items, and the number will not be identical with those used on factory assemblies. Use only the "Service Part Number" shown in this parts list when ordering replacements.

Translation: Your C402, C7, or whatever you wish to call it may have the 30-1227-7 on it. Philco said that 60-10105407 is the part to use when making a replacement.

However, there are no Philco distributors around anymore, so you have to use a modern generic replacement.

A 100 pF silver mica capacitor rated at 500 volts DC will work quite well as a replacement.

Edit: This is where a copy of the actual Philco service information would come in very handy. You can purchase the complete service information from Chuck, which is much better - and much more complete - than what you will find on Nostalgia Air.

http://www.philcorepairbench.com/schematics.htm