By not tracking well, what do you mean?:
1. The cutting path is out of place.
2. The movement of the media is out of place.
If the cutting path is out of place, this means whenever you forward and rewind the media, the wheels are always treading on the same place (the same path), so it is a problem with some of these items: the belts, the pulleys, the encoder of the engine or one of the engines itself. If the last time you replaced belts (I mean the belts of the motors), it was more than 2 or 3 years ago I would recommend you to get them new, it is a minimun amount of money compared to the improvement of the cut. Is there any pattern on this tracking problem? I mean, is the problem always having the same mistake, let´s say, to the right, for example? Are you experiencing any static power problem (usually it gives problem on the X axis, when you have not a proper grounding, and after some time working, or with desings consisting of long rectangles, like bar codes and that sort of things).
If the movement of the media is out of place, this implies that when you move the media 2 meters to the front for example, and you rewind the media to the origin, the path that the wheels (pinch rollers technicians call them) make is wider than what it should be, so, when rewinding the wheels are not coming for the same place they went when forwarding. This is related to the wheels themselves, the drive drum, as tech has told you: are you cutting vinyl itself? or sandblast mask? or a harder material? Hard materials may brake the feeding of the media sometimes, specially if they need a high pressure value to be cut.
If this began to happen from some time to know, and you are working under the same conditions, the motor belts would be my first option and priority.
Hope to be helping a bit, tell us if you managed to get your problem solved.
