Hi. If your machine is constantly jamming, the problem could be that you have broken stripper plates. These are the plastic (or sometimes metal) plates that sit between the cutters and make the paper fall into the bin. If they are broken or snapped off the paper can just constantly go around the cutters until it Jams. If you have any questions or would like any more help please visit www.shredderrepair.co.uk and we would be more than happy to help.
Matt