|Have you dropped this laptop, or have you spilled liquid on it? |
There are three things that can commonly cause no video on the built in display, if you haven't done either of the above:
A problem with the backlight (common after the laptop has been used a lot) , or with the voltage inverter that supplies high voltage to the backlight (not anywhere near as common), or with the wiring between the display and the base of the laptop, which is damaged due to wear (opening and closing the laptop frequently) , usually right where it passes through the hinge area (common after the laptop has been used a lot).
Did you change the wiring between the display and the base of the computer ?
If an external monitor works fine, you probably need to change that wiring. If an external monitor produces no display, the video adapter is damaged. On most laptops the video adapter is built into the mboard and cannot be removed - in that case, you must replace the mboard.
Laptop no video (or video problems), and battery, AC adapter, power jack T shooting.
See response 1:
DO NOT plug in or unplug a monitor's video cable into / from a video port while the computer is running. Doing so can damage the monitor's circuits and/or the video adapter's circuits.
Some laptops will display on an external monitor without you having to do anything.
If you get no video on an external monitor, some laptops have a key combo that you must press to toggle the display to external video only / sometimes both / built in display video only - see the Owner's or User's manual for the model.
Are you SURE the proper keys for that are Fn and F4 ??