Bassman 5f6a and Champ 5f1 Cathode / Fixed Bias Switching

[duffman0733]

After scouring the web I cannot find, nor figure out the proper way to wire a fixed/adjustable bias switch for these two amps. Can someone either explain...

[crthnsn]

I've been struggling with this for a long time.
The amp would work fine until it heated up and then would shut off.
I checked for bad solder...