I'll try to borrow a digicam and do a DIY on it. Yes... you have to replace the zinc block once in a while when I gets really rusted up. You can also remove all the zinc oxide with a wire brush.
On mine I used a ground wire and put the block in the plastic box for the cleanliness of it... but you could also just bolt up the zinc block directly to the chassis. The important thing with this is to keep a good ground btw the block and the car's chassis.
It's that simple!!! :thumbup: