1--Sometimes when attempting to adjust a screenmode in P96,
the created modes confuse the monitor so badly that I can't get
it to go back to the proper WB display without turning the
monitor off. Could your problem be similar? Perhaps you are
in a mode that is at the edge of your monitor's capability.
Admittedly, it sounds like you don't use a graphics card.
2--With one of the DCE scan doubler/flicker fixers, I had
difficulty rebooting (sometimes initially booting ) the machine.
It seemed to be due to the adapter on the Lisa (?) chip not
fitting tightly.
Good luck.