[tsac]

This may help


The backlighting for the screen and keyboard is designed to adjust automatically so that you can use your device in various lighting conditions.
Set the brightness of the backlighting
1. On the Home screen or in a folder, click the Options icon.
2. Click Screen/Keyboard.
3. Set the Backlight Brightness field.
4. Press the Menu key.
5. Click Save.
Set how long backlighting remains on
1. On the Home screen or in a folder, click the Options icon.
2. Click Screen/Keyboard.
3. Set the Backlight Timeout field.
4. Press the Menu key.
5. Click Save.
Stop backlighting from dimming automatically
1. On the Home screen or in a folder, click the Options icon.
2. Click Screen/Keyboard.
3. Change the Automatically Dim Backlight field to Off.
4. Press the Menu key.
5. Click Save.