iSight Problem

[mikey4020]

I am having a problem with the iSight camera in my early 2009 iMac. Regardless of application used, PhotoBooth, FaceTime etc when the camera is first initialised I get nothing but a screen with a purple tint. Today after various attempts at fixing this from tips found on the net I tapped the case behind the camera. It flickered a few times and worked as normal. So then I quit FaceTime and was able to replicate the same steps, purple screen...tap...works!! Is it safe to say theres some connection loose in the camera and is it worth having it looked at? The machine was purchased in the UK from the HE store and as such is under warranty until 2012.