I was shooting and Blue bars appeared over my

I was shooting with my Panasonic DVX100B and Blue Bars appeared over my image. Without another camera, we had to keep shooting. And when I imported footage from a deck the footage was fine. But, the blue bars remain on the camera images. I've used a head cleaner a few times and finally took it in to a repair shop. They said I had to replace my heads, which meant replacing the whole assembly. They quoted about $500-$600 just for the part. Does all this sound right? Is there any other possiblity than damaged heads? Also is it possible to replace the heads/assembly myself? I successfully replaced my hardrive on my Powerbook G4, which ended up being quite simple actually. Thanks for all your help, I'm desperate!