Mark M Irondale , AL October 25, 2018 Appliance: Samsung Refrigerator RB195BSSW/XAA Samsung Refrigerator Rb195bssw/Xaa / : Freezer defrost wasn't working. How to replace Refrigerator Main Control Board Assembly. Replaced the main control board Do-It-Yourself Rating: Repair Time Estimate: 15-30 minutes