Not a yoke, but just about everything else. The absence of any video turned out to be a heater-cathode short. Adding a separate transformer gave this result
clearly suffering from some drive problems. many adjustments and unfruitful tube substitutions later it looks like this
there are actually two narrow lines, the second is nearly invisible. There's precious little in Riders about setup of the Horizontal. So very much nearer
and farther! Ideas?