dishwasher not washing bottom tray?

I have same problem but I think disk is sticking as it turns occasionally. How do you get access to the small motor? I know you have to turn d/washer upside down but then get nowhere trying to remove base.

Andy
October 2011

on further inspection i discovered that the disc is operated by a small motor which had burned its connections but as the dishwasher is 6 years old i decided not to replace the unit but instead drilled a small hole through the disc and reassembled the unit which now washes fine again. this fix can actually be done from inside the machine without any dismantling

tom
February 2011