I have a brother 910 knitting machine with rubber. Attached and went across first row, attached comb with wire hung weights but it does not want to pass left to right. I pulled down on comb thinking it was being caught have my settings where book says and afraid to jam machine. Any advise? I have watched videos and am confident I am doing what I should. My machine has been recently serviced and in great condition and knits fine. Just the ribber. I must be missing something.