Another vertical output transformer????

[Zenith26kc20]

There is a screen grid electrolytic (40mfd@475V), a cathode electrolytic (100mfd@50 volts). The rest are the feedback/shaping caps. I've ESR'ed the electrolytics and replaced the integrator. The feedback caps have been replaced a while back. I've checked the old transformers after a couple of hours running and it's not hot.
The rewinder also noted the wire used in the transformer is not exactly a real high voltage type wire. I guess when these were made, cost was a bit of an object.
Also, when running properly, vertical is very stable and has a full screen. I thought if the boost voltage was high it could cause a problem but the transformer/output tube is fed from 390 volts.
Funny thing is my other Zenith has a 94-2345 and it failed exactly the same way. They short to the convergence winding, the one to ground. I plugged the old thordarson primary into 120 volts AC to see if the transformer would overheat but it say all day hooked to my scope. I did find out it is a 10 to one ratio for just the vertical output part.