[MrFixr55]

Hi Greg,
I just looked at the schematic from N/A, Link below:

http://www.nostalgiaair.org/PagesByModel...017637.pdf

There appears to be a switch component that grounds the detector plate for phono operation. This may be gummed up, broken, not wired correctly by a previous service person, etc. There appears to also be switches that determine whether the 6SQ7 or the 6SK7 are being used for the 1st audio amp. The 6SQ7 appears to be the 1st audio amp for the mic, where the 6SK7 is the first audio amp for the radio and phone. The 6SK7 is not commonly used as an audio amp, but my Zenith 6S52 chassis uses a 6H6 as a detector and a 6SK7 as a 1st audio. Sound from this radio is SWEET!

So bottom line is to trace all those wires from both the pickup tone arm and the recorder tone arm and ohm the contacts of the switch that is supposed to ground the diode detector plate of the 6SQ7.

Hope that helps.