[old_tv_nut]

It appears DC-wise that the 1800 ohm is in parallel with a 1500 ohm resistor on the delay line input, so the 750 ohm in circuit reading may be normal, but it won't hurt to check. But also ckeck that the coil in series with the delay line input (9 ohms) isn't open.

In theory, the convergence controls should affect only the edges, correct. I think the three diodes in the convergence circuit are meant to provide the stable center. So it may be worth checking them. But note that the instructions say that center touch up may be necessary after adjusting the edges.

Just for comparison, the CTC-5 did not have diodes, and adjusting the dynamic convergence moved the edges one way and the center in the opposite direction. The null points were somewhere between the center and the edges - so adjusting the dynamics always required readjusting the DC (center).