[tsac]

Ok , last shot,
Playing with mine I found the display can be set really really low.
It might be worth checking.

Set options for backlighting
1. On the home screen or in a folder, click the Options icon.
2. Click Display > Screen Display.
3. Do any of the following:
To change the brightness of the backlight for the screen, change the Backlight Brightness
field.
To change the length of time that the backlight stays on when you're not touching your
BlackBerry® smartphone, change the Backlight Timeout field.
To stop the backlight from adjusting to lighting conditions, clear the Automatically Dim
Backlight checkbox.
4. Press the BB-Button to save.