How can I fix my Frigidaire Ultra Quiet dishwasher?

Some time ago I had a repairman to my house to fix my Frigidaire Ultra Quiet dishwasher that was not cleaning properly. He removed the rotating arm at the bottom of the dishwasher and removed something else and found some toothpicks lodge there that prevented something (a valve?) from moving properly. I am starting to have the same problem and want to check to see if there is a blockage. How to I remove that rotating arm and whatver else I need to remove?