[davemc]

Perhaps the schematic here would shed some light.
http://www.philcoradio.com/schema.htm

Baring that, try Chuck's site http://www.philcorepairbench.com/
and order a copy of the service documentation.

Neither Riders or the schematic on philcoradio.com has the values for C23 - already checked that as well as searching the forums. I would hesitate to order service documentation at this time, since it's not clear that would answer the question. Maybe someone can confirm, and if that's the case, it would be worth it!

Thanks,
Dave