Randall RT2/50 No Sound out of Channel 1

[bbaug14]

I have a problem. I have no sound coming from the 6L6 (channel 1) of my power amp. I've tried replacing tubes and I've checked the fuses. Both are fine. I can get good DC Volt readings on the tubes, but when I select channel 1, no sound. Any suggestions? Channel 2 works fine.