I think it is from the same series that I have. I don't think it is a computerized machine but my Bernina 1530 is still quilting with hardly any repairs except for maintenance. I also own a 1020 that is not computerized. I am not sure about the serpentine stitch. You can go to eBay and see if any have sold recently. They do have a tendency to hold their value since very little goes wrong with them.
http://www.ebay.com/sch/i.html?_from...ina+931&_sop=3