Is this a screen resistor problem?

[wcrankshaw]

Excellent. I'll have to wait a bit to do this, but I'll report back.

[cagamp1]

Sorry I read your bias info wrong and my thinking went in the opposite direction. So, you are underbiased. 480V to 323V @ the screen???...big difference. Now you seem low. Like MWJB suggested, list all of the voltages for comparison sake. Is there still no sound?

You may want to center the depth pot and then move it around while noting readings to get a feel of how it is affecting the bias voltages before it, after it and at the grid pins to make sure the pot is working properly. Do this before changing any resistors.

What brand and model transformers?