Originally Posted by quiltnchik
I would return it for a refund, seriously. The reason I say this is because I have the exact same problem with my Janome 6600P - the 7700's precursor - and have never found a way to remedy it. It aggravates me because the "P" stands for "Professional" and, in my opinion, a professional machine should have a strong enough motor/feed dogs to go right over seams without a hitch; my Janome 4800 (much smaller machine) sews over anything, and it was half the price of the 6600P!
Trish, according to several here, the problem is actually in the FOOT, not with the motor. Read some of the previous posts for more details and check out the video. I'm going to give it the benefit of the doubt, and wait to see if the new foot fixes the problem. If it does, I am a happy camper. The machine really is great except for that. The Youtube video shows it sewing over really thick fabric, and evidently it is the FOOT causing the problem. Since they have redesigned the foot and it is available free, I'll wait a bit.