Jon N Fort Wayne , IN January 30, 2018 Appliance: General Electric Free Standing Microwave SCA2000BBB03 Ge Microwave Sca2000bbb03: Calcium build up on dishwaster parts. How to replace Lower Spray Arm. Replaced filter and moving blades then used CLR to reduce remaining build up. Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes