This is the most accurate description yet of my symptoms. The real issue is that in the car, at start up in daylight, the display sometimes is so dim that you can only adjust by feel (down, 4 lefts, down...). This is pretty messy. Frequently it will boot on AC at full brightness and then dim itself with no external inputs.

I do not see any temperature dependence but often I do see 60% brightness dimmer than 50% (just an example of "randomness"), in the car or in the house, regardless of which way I try to change it (buttons, remote, knob).

I have a Mk2A, 10 GB, 04010.... date code.

Has anyone brought out the VFD bias to a DVM to watch this signal during changes?

Lynn