[dtvmcdonald]

The CT-100 will drive any 21" roundie as far as signals goes. It can easily be modified
to provide focus. The bigger tubes need a higher high voltage. That would have to be
provided by an external HV supply., which you can buy on ebay. I would be afraid of
trying to get a higher HV using a tripler from the horizontal output tube plate.

The big big problem is convergence. It would be a major problem to connect up a
roundie convergence board to it, but surely doable.

What I did before I got a new good 15GP22 for my CT-100 was hook it up
to a modern (~2000) Sony high grade pro monitor of the same size picture,
just sitting on top of the CT-100. This is essentially trivial ... its done with a
5x5 inch of perfboard with six garden type transistors, resistors, and three
trimmer caps, running off a wall-wart. It takes the three color signals from
the CT-100 directly from the CRT grid lead attachment pins and reduces
them to standard voltage 50 ohm lines. The green
provides sync.

The picture on the Sony is identical to that on the 15GP22 except for the much
finer stripe pitch and the fact that its rectangular.

This same circuit would of course drive an LCD flat display inside the cabinet.

I just unplugged the HV and focus and regulator tubes, leaving the rest of the
sweep operational. That's needed to keep the various internal sync loops working.
If I unplugged the DC restorer tube it made no difference, because the monitor redoes that.