[compucat]

When I first restored my Motorola 9VT1 with the TS-18 chassis, I used ceramic disk caps not knowing any better. The HV and horizontal were fine but I could not get good vertical linearity without putting two or three in parallel across each deflection plate. i have since replaced them all with the white tubulars from Allied of correct value and all is well. The Motorola has no linearity controls, just size and position much like an oscilloscope which is more or less what an electrostatic TV is. I have not run into the vertical bunching like you describe but one open cap makes sense that it would cause that. Very interesting thread and experiment. I personally really like electrostatic sets and find they are fun to work on.