cs 1510
i have a cs1510 that is giving me a variety of copy quality problems when feeding through the sdf. i have replaced the wire harness from the sdf to the main body, i have also checked the cables on the optics. it will make good copies for a while then suddenly it all goes to heck. i know that there is something that i am missing, but have limited experience on this machine. any help would be appreciated. thanks in advance.