Dave Belles stated that a couple of units went out the door with a missing jumper. Mine could be one of them.
With the 21A powered off or powered on, there's no change in "glow intensity" of the filaments.
I also have a 20A and the chassis above the tubes gets slightly warm but there is no visible glow in any of the 4 tubes.
With the 21A powered off or powered on, there's no change in "glow intensity" of the filaments.
I also have a 20A and the chassis above the tubes gets slightly warm but there is no visible glow in any of the 4 tubes.