• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Napa Acoustic 208A or Mistral DT 307B

I have a Napa Acoustic 208A AKA Mistral DT 307B hybrid integrated, with a pair of 6N1 in the pre. Napa Acoustic is no longer in business. Only the right channel works. Only the right tube lights up. And I have swapped left and right tubes, no change.
I have opened up the unit and checked the electrical connections. Is there an internal component that will fix it most of the time? Troubleshooting this is not in my skill set. Switching out a component is.
Thanks,
Joseph