Thought I might post this since it may be useful to someone else:   I have the green on black optrex displays on my sequencer that I have never been happy with since I could never really dial in a good balance between brightness and contrast and there were weird bright spots on the display as well.  The backlight was always shining through too much at lower settings and it seemed that the only way to get it acceptable was to make everything super bright which I was not fond of. This was more p