Brother xl-3022 sewing machine. My sewing machine will not sew zig zag stitches or any of the

Question

My sewing machine will not sew zig zag stitches or any of the other sititches aviable on it because it seems to not be picking up the bobbin thread all the time the needle moves to the right positions for the stitches but does not produce the correct stitch I have changed needles, rethreaded, checked bobbin and no good results. I don't know anything about how to check the timing but think this may be a factor any help would be greatly appreciated.I have a XL-3010 & it will not Zig-Zag or any side stitch.It will go side to side but will not pick up the right side of stitch.HELP!!