Erratic convergence and audio on RCA RPTV

I own a 46" RCA rear projection tv model # P46810LV wich is about seven years old. For some time now whenever I turn the tv on, it would show fine but after a few minutes, I would start getting images with the colors separated i.e blue, red and green. I have tried unsucessfully to correct the problem from the troubleshooting guide.
Recently, I started having problems with the audio as well. Sometimes when I turn the set on it would work fine and at other times I would get nothing but static. Is there some part in the tv that has become defective and could be affecting both the video and audio?