Machine keeps jamming

try changing the needle--make sure it's the correct one for the fabric
being sewed
rethread the machine ---using every thread guide
try using a different bobbin
try turning the bobbin over the other direction
clean under the needle plate and in the bobbin area for lint
also could be a timing problem and the machine would need to be
checked at a sewing machine repair shop

then they didn't not fix the machine,, I suggest to take the machine back to them
& tell them how much you don't appricate it's still doing the same thing.
I've heard of this happening before.

If it is a mechanical machine, a thorough clean and oil may be very helpful. (You are wise to avoid using the machine until the problem is addressed as the motor could be damaged.)

Wheel on right side that controls the needle up and down is very tight...

something is jammed further then you can see. stop. be patient here. if unplugging and plugging it back on does not fix. just take a deep breath, you do not want it to break. its just a machine. i would suggest taking it to a shop to see if they can clear your jam by an adjustment, for free at your local store. or a tune up of $50.00 bucks . this machine is well worth it! its a bizarre thing that has happened, but to force it you could really hurt it more then you know.

The UPPER thread is not threaded through the machine correctly.

ask at manualfox.com
They have it.

Probably just the needle. Try turning it 180 degrees

Hey if you need a new manual go to this link www.ifixmachines.com and dont forget to put this code (150t) so you can get $1.50 discount. Hope this help.. By the way the manual cost only $10. BYE

SEWING MACHINES ARE TRICKY...JUST ONE LITTLE THING AND THEY DON'T WORK. SINCE YOU SAY IT JUST WON'T SEW LETS START AT THE BEGINNING. FIRST, I WILL ASSUME THAT THE BOBBINS YOU ARE USING AND THE NEEDLES CAME WITH THE MACHINE WHEN IT WAS NEW. O.K. NOW, TENSION MAKES YOUR MACHINE SO IT CAN SEW. YOU HAVE TO WIND YOUR BOBBINS WITH THE CORRECT TENSION, OR YOU WILL A BEAUTIFUL STITCH ON TOP AND YOUR MACHINE WILL STOP DEAD WITH A MESS ON THE BOTTOM OF YOUR CLOTH. YOUR MACHINE MAY OR MAY NOT HAVE A TENSION SPRING THAT NEEDS TO BE SET WHEN YOU THREAD YOUR MACHINE, BUT MOST NEW MACHINES DO NOT HAVE IT. WHEN YOU PUT YOUR BOBBIN INTO THE HOLDER, MAKE SURE YOU ARE PUTTING IT IN THE CORRECT WAY--IT WON'T WORK IF IT IS IN BACKWARDS. NEEDLES, THE WRONG NEEDLE CAN CAUSE YOUR MACHINE NOT TO WORK. A NEEDLE THAT IS SLIGHTLY BENT WILL NOT WORK. ON YOUR BOBBIN HOLDER, THERE IS A SCREW, MAYBE SOMEONE MISADJUSTED IT. THIS WILL MAKE YOUR MACHINE NOT WORK. IF YOU HAVE DINGS IN YOUR PLATE, IT WILL CUT YOUR THREAD AS YOU SEW, YOU NEED TO USE A PIECE OF CROCUS CLOTH TO FILE THEM DOWN. THESE HAPPEN WHEN A NEEDLE GETS BENT AND HITS THE PLATE INSTEAD OF GOING DOWN TO GRAB THE THREAD FROM THE BOBBIN. MAYBE SOMEONE IN A LOCAL SEWING SHOP, OR QUILT SHOP CAN HELP YOU BETTER, AS MACHINE PROBLEMS ARE HARD TO DIAGNOSE WITHOUT HAVING THE MACHINE TO NOODLE WITH IN FRONT OF YOU. MAYBE ONE OF MY IDEAS WILL HELP...I HOPE SO.