When the machine jammed, it threw the machine out of time and when the needle comes down it is hitting on the shuttle.
The best way to fix it if you are not familiar with the mechanics, is to take it to a professional and have the hook reset.
Generally, when you remove the bobbin and the retaining ring on the older models, there are two screws that hold the race on the shaft. Loosen the screws, set the hook to the needle, and retighten them. I must caution you, however, this process has to be done by someone who knows how to set the hook. It's not hard to do, but must be precise.
If you have never attempted this process, again, the best thing to do is take it to a professional.
Patricia Murdock
September 2007