I'm not sure I would be willing to mess with a computerized sewing machine. However, many times a service manual will address some issues. I found a service manual for the Singer Quantum Stylist 9960 at
https://www.manualslib.com/manual/28...page=23#manual I also found a reddit post that seemed to indicate it may be a fuse per a reply by ladybugmyheart at
https://www.reddit.com/r/sewhelp/com...ing/?rdt=47610
There is also a question about this problem on sewing.patternreview but don't know if it got settled
https://sewing.patternreview.com/Sew...s/topic/114902
it wasn't on the first page and I'm not a member to see the second page.