Answer:
The motherboard sends a signal to the inverter board telling it when to switch the backlight on. If there is a fault on the motherboard then the inverter board will not receive a signal and therefore not switch the backlight on. It may be possible to check the input voltages to the inverter board with a multimeter but if you have eliminated the previous items I have found this to be quite a commom fault. NB If you connect your laptop to an external monitor and get a good picture this only proves that the video card is OK, there could still be a fault on the motherboard which is preventing your screen from illuminating.
| Previous Question | Next Question |
| A question I am often asked is "How can I tell if the backlight or inverter has failed on my laptop/monitor as I can only just make out an image? | Explain APM? |