I also would reposition the needle. It needs to have the flat side to the back, and be pushed well up the shaft before you tighten the screw on the side. Also, check that your bobbin case is in correctly. My Brother machine has marks on the bobbin case which have to match up with other marks when you replace the case after cleaning it. These are the only things I can think of. If you've tried all and still doesn't work, then sounds like the machine wil have to be looked at by a Janome mechanic.