Janome 1560 timing out please help so it doesnt...

Question

Hi I have a janome 1560. The needle is going down into the bobbin housing and not at the right time so it gets stuck , making a horrible noise in the rosess. It will not now work even turning it slowly by hand . The needle goes into a hole on the bobbin housing and does not lift in time. Then the wheel gets stuck.. Can you tell me how to fix this problem myself. I need to get it fixed to finish making some curtains asap. Many thanks Tansy