[MrFixr55]

Hi Joseph,

Unless the preamp tube is gassy, I don't really think that the weak but good tube will cause distortion.

The original turntable in this unit used a unique "Bem of Light" pickup, described in the Philco documentation for this set. I have never troubleshot (or even seen) the "BOL" (Beam of Light) pickup, but there are 2 factors here. The pickup emits a signal much smaller than a crystal or ceramic cartridge in common usage in the 1940s and 1950s, hence the extra amp stage. In addition, the light source appears to be driven by the radio's local oscillator. This was some serious "tech" for 1940 -1941, and I believe it was unique to Philco.

Verify that the wafer switch is fully clean and not intermittent. Another "divide and conquer" technique would be to substitute another signal for the phono pickup. Either a turntable with a magnetic pickup or a dynamic mic would work. A line level source such as a CD player, MP3 or computer would require a lot of attenuation. If the sound through the preamp is good with the external signal but bad with the BOL, continue to troubleshoot the pickup. If the BOL has been replaced by a crystal or ceramic cartridge, then this is likely your problem. You would likely overdrive the preamp with a crystal or ceramic cartridge. In addition, I assume that if this is the original turntable, it plays only 78RPM records. The stylus must be for 78RPM records, as the groves are wider than 33 1/3 or 45 RPM records. If you can't find a BOL pickup, a GE RPX would be a good substitute. There are also modern magnetic pickups still made, particularly by Shure and Audio Technica. Ensure that you buy a 78RPM stylus for the pickup.

If the turntable has been replaced, and has a crystal or ceramic pickup, then this (overdriving the preamp) is your issue. If you intend to use a crystal or ceramic pickup, then you must bypass the preamp by disconnecting Cap # 44 from the wafer switch at point C9A on the schematic and connecting the pickup directly there. Alternately, either attenuate the signal from the pickup or replace the cartridge with a magnetic one. If the turntable is a 3 speed, then consider a cartridge marketed for "Scratch DJs". (They now prefer to call themselves "turntablists" as they consider themselves as playing a musical instrument.)

Hope this helps!