Welcome to the QB from SE Michigan! I am not sure about your machine. Machines of that era frequently have either electronic problems or problems with the plastic parts. This can be very frustrating since for many machines the parts are no longer available. I will late a good vintage metal machine any day of the week. I see many different models in thrift shops from time to time. It may be a good idea for you since you hare sewing heavier fabrics right now or going through more layers than usual. I don't' know anything about the Singer heavy duty machine. One thing I do know is that there are many helpful folks here to help you test and try out different machine. Again welcome ot the QB. I hope you get a new machine or get this fixed or even retire it soon.