[old_tv_nut]

The customer control is DC only, so it would be set for proper convergence at the center.

The H and V waveforms will have a specific polarity with variable amplitude because the beams must converge at a sharper angle at picture center than at the edges due to the geometry of scanning a flat surface.

I also note that the transformer wires have different colors on each end of the winding, which would indicate polarity was important.

So yes, it appears you have a 50/50 chance of needing an extra inverting stage.

Following your progress with baited breath!