The adhesive dots are all in place--no problem.
In manual mode, at 8 stitches/inch there is the amount of vibration one would expect when using a large machine. At 9 there is a beginning of unusual vibration and by 9 1/2 the machine head begins to "jump" up and down. At 10 the machine exhibits most "jumping" or "bouncing". At 11 the "jumping" remains; at 11 1/2 it slows and then at 12 it becomes as smooth as it does at 8. When the "jumping" occurs the handles vibrate to the point that the sensation travels to hands and wrists. I don't know what you are referring to when using the phrase, "the eccentric of the fly wheel". When you mention the "covers" are you referring to the outer metal of the machine? If so, they are all tight, in place, and not vibrating. I've also noticed that tiny dark specks appear on the cloth being used for practicing. When touched, they smudge. Obviously not metal, but something is being generated.
Perhaps it is obvious that I am extremely disappointed, worried, and terribly frustrated at this point but I feel the need to make this clear. Usually calm, I am losing patience and am angry. This is not what I had expected from an APQS product.
Please note that when I first used the machine for about 30 minutes it did not have these problems. It was not in use for a week and a half. The machine was NOT moved, touched, or handled. It was in a suitable area of a large bedroom. When I began using it again the vibration was noticed.
Thank you for your efforts in trying to find the solutions.