I have a dyanco st-70- I am not a tech, and only have a very basic understanding of electronics.
I replaced the caps on the driver board, the quad cap capacitor, the 50uf caps, and the choke. During this work, I managed to break two resistor leads. (1) the 6.8k ohm, 2w on the quad cap lug, and (2) the 10k ohm, 2w on the terminal strip. I wasnt able to find replacements, so I soldered a small wire to replace the broken lead on both resistors, and re-attached with solder. However, my meter reads the 6.8k to be 5.8k.
With tubes in, and without a signal to amplify, I am able to set the 1.56v bias setting. When I play music through the amp, and monitor the bias voltage, it varies and slowly climbs reaching over 2v and I turn the bias adjustment pots back to compensate, but it continues to climb - I then turn it off before another tube gets damaged.
Are there any other checks I can do which would pinpoint my problem?
How do I get a stable bias voltage?