The 830 is not for the faint of heart. It is a machine that only likes to do one task at a time. When you are threading it wait until the machine stops its bumps and grinds before continuing. Don't try to thread it while you are winding a bobbin, etc. Many people blame the machine for various problems but it is mostly user error. It is also fussy about what thread is used. But with all that, I have the 830 and love it!