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My metal cab zenith 20X1C36 started acting up on me, lots of vert jitter, bad retrace, general mayhem.

I pulled the convergence plug and other than the loss of dynamic convergence it went back to normal.

I plugged in a spare converge board, just to see if that could be it, same issue, vert scan gets fubar.

disconnect the two leads from the vert out secondary that goes to the convergence, and plug back in, its better (getting the horz pulse) but clearly its the vert out transformer.

I did some voltage reading getting some real odd things from the suspect winding to ground I get 25-50vac (25 on the simpson 260, 50 on a cheap DMM). I presume its got to do with different loading and maybe the odd ball AC wave pattern that I am sure its putting out.

My guess is a break down of the insulation that only shows up with a strong pulse (prob arcing inside the transformer). I could not get any leakage path with even my VTVM, then tried the leakage test from my cap tester 450vdc still no leakage. So I presume its takes a strong pulse to show up.

anyhoo time for another transformer replacement, this is about the 3rd zenith in the past couple years that has had this fail. Last one was a hard short that took out a 1k power resistor, this one is not that bad, yet.