Calibrating PSX rom reader

[Geminiff7]

When I play my backups, the movies and sound are somtimes choppy or break up badly. At first I thought it was the media, but I databased some of my titles to see if the problems were consistent and they were not for any one type of media. Most of my media is verbatim now. I was wondering if there were any way to recalibrate the psx reader to help correct for this problem. I have an older used 5501 model. Thanks.