This message is for those who want to learn from my experience.
Was it only the old battery or something else as well? I still do
not know. What I should have done yesterday was to borrow a
monitor from school and try it. But I replaced the battery first.
For many hours all was fine; with the old battery I had a
pincushion effect about every 10 minutes. I was fixing it in
the Monitor control panel. Several hour was a good sign and
I was optimistic.
But today old symptoms started to appear more often and
finally the monitor became black. I was turning it on and
off (sometimes successfully activating the screen). Finally
even this stopped working. How to shot down a Mac when
the monitor is black?
At that point I borrowed an old Mac LC monitor and all
symptoms disappeared. Will it last? I hope so; the computer
was on for many hours and all has been normal so far.
I think the AppleVision monitor is really sick and needs a
professional hand. I wish I could buy a used replacement
monitor for peanuts, as Bernard did yesterday.
Ludwik Kowalski