Brother XR3340 Sewing machine repair E6 error, 2020 03 15

20200315 Clip showing repair of Brother XR3340 sewing machine. The repeat error was E6 meaning, the motor is jammed. Sometimes this can be caused by thread dust and particles, and a good cleaning can fix the problem. This time however, it required disassembly. The root cause failure was a jammed bushing on the bobbin driveshaft. It could have been caused by the belt tension set too high when it left the factory. This is a splined drive mechanism and unlike a standard Vbelt it doesn t need to be that tight to work as intended. Another possibility is that it could have been caused by dust contaminating the lubricating grease, gumming it, and eventually seizing it onto the driveshaft. Whatever the contributing factor, the bearing was so jammed that it required forceful removal using a hammer to drive the stuck bushing off of the driveshaft. After removing the bushing we cleaned the old grease and relubricated it. We reset the bobbin timing and reassembled the machine, and then, as can been seen, ran a suc