Inverter or backlight broken - How to identify?

I have a MacBook Mid 2007. The backlight turns quickly after powering on off. While shineing with a light on the display I can see everything is still working. So the issue is clearly backlight related. Now I need to identify if the issue is solved by replacing the inverter or the backlight itself.

So, I can always press many <F1> and then <F2> to get the light back on. The less bright I set the more stable it lights. I.e. having it in the brightest setting will turn it off after few seconds. The lowest setting works almost endless. It's not OS related, as it happens also when booting a live CD.

I had one event where the light was flickering very fast (something > 10Hz) and only one half of the screen was lightened.

Tapping against the display would turn it off as well.

So, replacing the inverter or the CCFL?