Why?As the back light bulb ages, it requires more current to stay on and start. Eventually, this current requirement will exceed the inverter's (a high voltage power supply) capability. This can lead to inverter damage (read: expensive).
SymptomsFor about a month or so, my back light starts off as red on startup and slowly returns to normal (white). This can take as much as 30 seconds to a minute. Much recently, my backlight has been turning off randomly, but the frequency has been slowly increasing. As of yesterday - I noticed a high pitched hum sound just before the light kicked off. My light would come on instantly if I hit the screen position switch. And lastly, if I turned the brightness down, most of the symptoms disappears - except the back light had a red tinge to it.
Solution1. Replace Bulb -- this is a $12 part
If problem persists:
2. Replace inverter -- a $70 part, however the bulb should always be replaced when the inverter is replaced.
Step 1: Cautions
WarningThe following procedure will, without a doubt, violate any warranty you have. But who has to know? Take it apart and reassemble properly, and you won't notice :D
Your back light uses high voltage and sensitive electronics. So please, take care as not to damage these rather expensive components. Static build up will damage these components.
LCD's are surprisingly flexible given their material. But, they are fragile and should be treated with great care. Never pull on any cords and always allow the screen to rest on a firm, non abrasive, surface.