[Patrick]

Are you injecting your signal through a .1 uF cap?  If not capacitively isolated, any DC on your Sig Gen lead could change the grid bias.

But don't ask me why the same thing doesn't happen at point "D".  It's a mystery to me.

Everything I've found on line says that the 7C5 is an acceptable substitute for the 7B5 & the specs look similar enough.

Yes, I'm using a .1 uf cap.

Here's the troubleshooting sheet I'm using. All voltages are good. C201 and C203 are both new. R202 is within tolerance. There is also no audio output when injecting a signal at test point "A" either. 

Even though the voltages checked out O.K. on pin 2 and pin 3 of the 7C5, could there be a problem with it? I should have just stuck in another tube. 

[Image: http://i1367.photobucket.com/albums/r796...fdnunr.jpg]