I have an IBM G70 monitor that has gone dark. It still has high voltage and
the CRT lights. So I think the trouble is in the logic circuitry or the
power supply.

When I switch it on I hear the degaussing surge. But when I press the
degauss button, nothing happens. In fact, none of the controls have any
effect.

Can anyone help? A schematic diagram of this or a similar unit would be of
immense assistance.

Thanks, Bob