it has a slug tuned input coil, i'll check the vswr. most golden screwdriver operators don't mess with them as they don't know the function,but it's possible. bias resistors are 49 ohm 5 watt and i replaced them when i recapped the amp just for gp. the part of the schematic that is missing is the voltage/ current selector switch and the input circuit board, both would be helpful.
tube amps are fun to work on, and i love the satisfaction when a repair is complete and the amp functions better or like new. started on this one because i finished my homebrew amp i now use. runs 2 3-400z's with 2 1000 watt microwave oven transformers in parrellel. 12- 650 mfd/ 450vdc computer grade caps for filter bank. drive it with homebrew 2- 6ju6 amp with a 1960 TV tranny. sorry to ramble, but i really enjoy tubes. thanks for the help, i have tons of stuff here if you need anything just ask.