[Amps] AL-80 (early) Loading control at full C

[Tony Brock-Fisher]

I'm the recent proud owner of an early (SN 151) AL-80. After reworking the power supply, I finally have it running (sort of). Latest 'issue' is the Loading control seems to be at or near full C (max CCW) position on 160, 80, 20 meters (haven't checked the others). It does make 500 watts CW out. I notice there is a modification to add ~10 diodes in series with cathode, I guess to reduce idling current and move towards AB1. Plate circuit looks good, no burns or scorch marks. Bandswitch looks excellent, as do doorknb caps on loading side.

Any ideas?

Could the bias change affect the tube load impedance and therefore the loading control position?

Thnaks,

Tony, K1KP