I have hit the switches and pots multiple times with DeoxIT. Unfortunately, some have responded better than others. The .02 coupling caps are ceramic disc. I was using the scope and tracing the signal. When I reached V10, I had signal on both sides of the cap for the left channel (pin 1), but only had signal on the plate side of the cap for the right channel (pin 6). I hoped that meant the cap was open, but it measures the same as the other one, so it must be something nearby pulling the signal down. Most likely a problem in my shielded cabling run to either the tone PC or the high filter switch. Will look more tonight. I was waiting on a set of matched tubes before deciding if the bias range needs to be modified. Thank you for the information on which resistor to change. I feel like I'm creating a lot of work for you responding to all my comments and questions - I'll try to minimize my posts until I have some positive results to report. Thanks for all the help!