Well, that's an interesting one, Jocky.

Which M-Series do you have there? The one with a colour display?

I've had a look at the manual, and notice that the colour display version has a board (connected to the LCD) called "LCD Inverter". Any clue(s) there, I wonder? think

Unfortunately the manual I have shows "block diagrams" only.

My only other guess would to be clear (reset) the config settings and see what results.

In passing, I'm wondering what the "Expanded Display Option" is all about.

Good Luck with that one, Mate. smile