I'm having a similar problem to some others I've seen on the forums; no text displayed on the dot3k.
Everything else seems to run just fine. RGB backlight and white LEDs run through scripts and acts as expected, but always without any text on the LCD itself.
I have run almost every example, with no error messages. The joystick returns the expected response in Terminal in those scripts that it plays a part.
If it's a problem with contrast then I can't detect even the faintest of text on the display. I've reinstalled twice, and used the display on three different machines (with different SD cards and OS) but still no text.
If it's a contrast problem, is there as way I can update the firmware or anything?