I checked all plugs today and finally called my LQS where we got our Artistic. Their repairman called Janome in New Jersey and they narrowed it down to one of two problems, based on my description. Unfortunately, neither repair can be done at home, so the LQS will call us again next week to arrange for them to pick up the machine and take it into the shop. I am so glad we purchased it from a local business with excellent customer service. The repairman was almost apologetic about having to bring it in, but since they are going to pick it up and we don't have to worry about packing it up or shipping it out, I am not complaining!