Problem with broken inverter
Information about the problem of a broken display power inverter.
If your displays backlight doesn't come on, the cause may be a broken inverter. A typical symptom is that the backlight comes on for a second when you start your system, but goes off immediately again. Also, in that case you will be able to see something (very faint) on the screen when the surrounding is bright enough.
The inverter converts the low-voltage DC electricity from the battery to high-voltage AC to drive the fluorescent tube.
Affected Operating Systems
You can have IBM fix the problem if your ThinkPad is still in warranty. If not, a new inverter can commonly be purchased cheaply and replacing it is a quick and easy procedure on most ThinkPads. You will find it described in the hardware maintenace manual of your model. You should also check your power supply; out-of-specification voltage can lead to the same symptoms.