I too have had a terrible experience with this stupid litterbox. I purchased the Performa Litter box after getting tired of buying a littermaid every year for my three cats. First of all, I had the Performa all of two weeks when both of the triangular shaped pieces snapped off. I called the company and they in turn sent me the wrong pieces. After sending them a picture via e-mail as to just what exactly was broken, they sent me the right parts but no screws. That is when I discovered just how bad this this was put together. After taking the whole thing apart, I discovered that mechanism underneath was misaligned which caused the parts to break. In my attempt to fix it I discovered that aside from the plastic, there is nothing to secure the screws to the thing. So, if the plastic breaks you are just out of luck.
After two hours and by using my own screws I managed to get it to work again. I can't use the cover because it will jam. It rakes when it wants to and when it does the tines are spaced so far apart that it leaves a lot behind causing me to have to rake it myself. If anyone out there is considering getting this thing don't waste your money because it will surely waste your time. If you get it as a gift, ask the person does he still have the receipt.
It's a piece of crap.