Well, not the capacitors this time
.
The PSU board was OK also after replacing the caps.
Apparently the fault was on the video board.
Unfortunately beyond repair.
Its parts are now in the electronics waste bin after salvaging a few bits and pieces. So sad.
Its bother (Multiscync LCD 1550V) is now in place for the rest of its life.
Since it does not have a DVI port, I can now no longer display the screen of my HMO 1022 scope.
Maybe a small monitor with a DVI and a VGA port will drop off a bench somewhere - hopefully some time soon.