3GS backlight problem - HELP please!

Hi, Wondered if anyone can help with this. I did have a working 3GS iphone, took it apart to change the battery and now the screen is dim. Checked the 6R8 coil and it seems ok @ 0.5ohms. Only thing I noticed was the board side of pins 1/2/3 were a bit discoloured. Cleaned up the connector with fluxclean and all looks fine now. Not sure if this was an indication of some problem?

I also read that sometimes the track can break between IC 109B and pin3 of the LCD connector. Does anyone have precise details of this check? Is it 3rd pin down on the LCD connector from the side furthest away from the camera and nearest to the edge of the board and on the 109B its the side nearest the edge of the board and furthest away from the 6R8 coil. And these two points should be connected I presume? Currently they are not on my board! So does this mean a link is required?

Or any other ideas?

Thanks