Several years ago I gave my son a Minolta xtsi camera with a Sigma 28-200 AF lens. Last summer I put that lens on my Sony a100 and the lens has not worked properly since, on any minolta or sony camera. The AF servo motor? is almost constantly in motion with a loud sort of ratcheting sound. I was under the impression that minolta lenses would work OK on the Sony. Is there a solution?

Cameras - Sigma - AF 28-200 Lens