I have a Dell D620 (1 of 3 actually) and the screen is very dark. Not dark as in the inverter has gone, just dark. The interesting thing is when you press the function+arrow keys to make it darker or brighter the steps it takes are not sequential, they are random.

I first noticed it with a fresh XP SP3 install. I opened it up and reseated the video cable ont he motherboard only, I didnt bother with the LCD itself. I went into the BIOS and disabled the ambient light sensor, adjusted the defaults for both battery and adaptor settings to high (by default they were very low) and switched from the dock graphics being the default to the video card itself.

Doing all this did improve things, but only very slightly.

I then tried a clean install of W8 Pro and did the same with the updates and drivers and whilst its a little brighter its still poor.

The viewing angles are also terrible, if you're not sitting directly face on you can barely see anything at all.

My unerstanding is when an inverter goes the screen is completely dark but Ive not experienced anything like this before. We have two other and there screen are excellent.

Does anyone have any ideas ? One comment I saw on the web was the screen was unlikely to be the original Dell screen, but I thought they all used Samsungs.

Anyway, I'd be interested to know if anyone has seen this before.