My Brother EX660 'froze up'. The wheel wouldn't turn at all. My husband took it apart, oiled and cleaned it and it worked fine. I have since moved on to a Brother SQ9000. I am in the middle of my second quilt with it and it 'froze up'. I recognized the sound before it happened (remembering the same sound when it happened to the EX660) so I slowed my stitching to a crawl. I saw it stop. The wheel wouldn't turn. Husband wasn't home so I thought it through, what can I do to get back in business. I remembered him oiling the needle holder rod when he did the EX660.
Out comes the oil can. I removed the needle, flipped the machine upside down. Dripped oil onto the rod and let the oil slide into the machine (down the rod). In a minute or so I tried to turn the wheel. It was loose as a goose. No problem. So I have added this step to my routine (every now and then).
Disclaimer: I am not telling you to do it. I am telling you it worked for me. :thumbup: