Are you talking about the 990 that was made back in the early 80's? If so I bought mine in 1984 and have used it ever since. And I do a lot of sewing. Just this last year I had to have it serviced for the second time in it's entire life. As I remember it is the first computerized machine Viking ever made. I've always loved this machine and hope it keeps going for as long as I do.
I can't help you with info on the 980 but maybe Billy can. His name is Lostn51.