I had my Brother 1500 ps high speed machine at a class and it would not sew, just start and then just stop. When I got home the machine worked fine. The repairman said it wasn't getting enough power. ? It was plugged in a strip with other machines all going to one plug and all the other machines were sewing fine that was plugged in to it. No computer on this machine so it didn't hurt anything. I haven't had a problem since. I don't take any computerized machine to classes that I may have to share a plug with several people.