Stewart Warner T-711 help

[Electronic M]

If you don't have a scope at least check grid drive on the output tube (if too positive your probably killing your tube and fly). Also, check the screen voltage while you're at it...If grid drive is fine and screen is low, and the resistors are fine the damper is bad or there is some kinda open in the flyback circuit preventing it from drawing plate current (so all the cathode current goes to the screen instead of the plate and loads the screen grid down). If the screen takes too much current it might also put out some gas from the heating.