poor water pressure - dishes come out dirty

I unscrewed two plastic covers to get to the chopper. I found out that the blade fell off and could not be put back in place. As a result the filter behind it was all clogged. I replaced the whole thing with the new one and put the plastic covers back in place. The dishwasher works like a charm. The hard part was that the screws have proprietary heads, so it is hard to screw/unscrew them with a regular screwdriver. Other than that the exercise is trivial.