You'll enjoy 1200 stitches a minute for sure. You STOLE that machine...enjoy it. They are easy to open up but be careful. Only use triflow cause there's tons of plastic parts in there. DO NOT remove the handwheel unless you absolutely have to because they are plastic and can distort easily. Other than that ....Sew On!

I looked underside of the 707 and found out the hole giving access to the other motor brush. It look like I will not have to open up everything after all. Thanks Candace for the suggestion. The 707 stitches very well and run good once started, so I bet changing the brushes will solve the problem.
Dan, thanks for the recommandation about the 831; I remember my good old tech telling me that there is more plastic in the 8- vintage Bernina than in the 7-. I will be extra cautious on this one. Anyway it is in such a good shape that I don't feel it need anything for now. It sure run fast for such a mature lady!