Warren Block wrote:

And here's the controller board. Capacitors with a black mark are ones
that have been replaced:

http://www.wonkity.com/~wblock/kds/kds-controller.jpg

Working from largest downwards, I replaced all of the electrolytic
capacitors on the controller and the inverter board. Testing of the
removed capacitors showed that many had deteriorated to half or even a
tenth of their marked value. Yet nothing improved until the last five
on the controller. These were three 10 uF, 25V and two 22 uF, 16V near
the toroid inductor. One of the 22 uF was definitely bad.

And that cleared up the distortion. The monitor seems to be fine now.

--
Warren Block * Rapid City, South Dakota * USA