On Thu, 27 Nov 2003 20:34:00 +0100, "Reinhard"
wrote:

Try to get a good monitor test software from the web (like the Nokia
one). One of the tests gives a picture alternating between white
and black. If the picture widens considerably when switching from
black to white, that is a good indicator for poor High Voltage
regulation.
(Given the same deflection current, the picture is smaller if the
anode voltage is higher.)
H.