[WyTex]

Hi fellas -

I'm working on a PT-25.  It's been recapped, new filter caps, repaired speaker, tested and swapped tubes and lubricated volume pot.  However, there is clearly audio distortion. Cleaned the tube sockets and installed a few Philco nos tubes but no change. I suspect a resistor is the cause but the schematics I have do not give tube voltage values.  I had planned to simply test the resistors but many are stuffed into very small locations with hardly any wire to even clip to. 

Tube voltages would definitively reveal if there's a bad resistor correct? 
Could there be another cause?

Thanks!
Paul