Phone Frontal camera doesn't work

I have bought a LG 2x second-hand,so i don't have warranty.When i have tried the frontal camera had appeared an image with colors(blue,green,red,etc) then change it into a black image.I have CM7(2.3.7).The 8MP camera it's working perfectly!Maybe you know what is the problem(hardware or software).I really want to fix this inconvenient problem.Thanks you!