did you check the connection in the foot peddle? I ask because......get my viking all set up at new place and go to sew. nothing. check the connections...all set up. won't sew. take it apart...clean...won't sew...this goes on for a week of me moaning alternately with blinky blank machine something must of happened when we moved. So, finally trap my husband on a day off to go in there and look. He leans over the side and then asks what does this go to? I look at him and say that is the plug to the foot peddle, still clueless. He goes well, shouldn't it be plugged in too to the side of the machine? gee, it sewed.
I still haven't heard the end of it. I have also had the cord work lose where it plugs into the foot peddle. maybe just a lose connection or short wire? check that before taking it in. otherwise, go with it. working now and that is all that matters.