I think it is time I got off my arse and fixed a long running fault of my x68000 monitor.
Here is a video demonstrating the issue.
https://youtu.be/UkNC7NlNixk
As you can see the brightness tends to fluctuate erratically. The fluctuations are most erratic at the start, but calm down after a minute or two.
This is not a capacitor issue since I already recapped this thing to get rid of this problem and another erratic colour vanishing issue. The recap was completely unnecessary though, all the caps were fine. I managed to solve the colour issue by using the old tapping around the boards trick to locate a cold solder joint on the neck board.
The brightness issue though does not seem to be locatable by tapping around. It could still be a cold solder joint though.
With a simple arcade monitor I would just shotgun reflow all solder joints, but as with everything else on the x68000 the monitor is an over engineered monster with 3 large boards containing hundreds of components.
I am hoping to draw on expert knowledge to narrow down my search.
I suspect the problem causes the brightness to go up from normal, rather than down, if that somehow helps to isolate the issue. There is a knob on the front for brightness adjustment and even when I turn it to its lowest when the brightness fluctuates it tends to go very high. Higher than I would expect to be normal for the lowest brightness setting.
Any good advice chaps?