The cam gear is often cracked. This is my friend's 830 that her mother had stored in a shed for 10+ years. If you look closely at the top of the line where the red arrow points, you will see the crack in the gear. It will still move the needle bar in a zig zag pattern IF I have the two position lever on the top right pointed at the zig zag symbol, not the 1-20 symbol. I haven't run it with the motor since discovering the crack for fear of further damage. I had to slowly turn the hand wheel through a full rotation while watching the gear to spot this crack. The Bernina 701 minimatic that we bought from goodwill also had a larger crack in the same gear. It wouldn't zigzag. It cost $24 for me to replace the gear and $100 to have the timing fixed at a local sewing machine shop. There are great tutorials on how to do the repair, but I will not attempt it on a high value machine like the 830 record.[ATTACH=CONFIG]579990[/ATTACH]