When I turn the knob to move the needle to catch the bobbin thread, it hits something underneath and won't keep going down. The same thing happens when I turn the knob in either direction. It's like it won't make a full rotation. It started happening after my fabric jammed and I got an E6 error. I pulled apart what I could, but there is no jammed thread anywhere that I can see.

On the right side you have two knobs to make adjustments. The lower knob will move the needle left or right so it won't hit the bobbin holder.

The bobbin might have a bunch of thread off it inside the compartment here the bobbin is. Also, make sure it's thread correctly, that can goof things up to.

Is the knob on the side, where you loosen the needle to rewind the bobbin, tightened? Also, there may be some threads in the bobbin case messing things up. Unplug the machine if you are checking the bobbin case.

First change your needle... it's probably bent and make sure you are using a needle FOR Denim in a size 18. Hand run the machine... if you still feel it hitting something... it is out of time. Take it in for repair.

try changing the needle
rethread the machine top & bobbin
make sure to use every thread guide
make sure the bobbin is not over wound
make sure the bobbin is turned the right way in the bobbin case
make sure the bobbin is not warped or damaged
if you've done all these things then it's also possible that the machine
is out of time & needs to be checked at a repair shop

try changing the needle
rethread the machine top & bobbin
make sure the bobbin is inserted correctly
also make sure the thread has not come off the thread take up lever
if none of these suggestions help, then you should consider
taking the machine to have it service, to see if it's out of time

try these suggestions
1. change needle--flat side to the back of the machine
2. needle must the correct one for the fabric
3. check the bobbin to make sure it's not damaged or warped
4. check the bobbin case( the thing that holds the bobbin) to see if there
are any burrs on it or see if it's damaged is some way
make sure the bobbin case fit's snuggly into the hookrace
5.it's also possible that the machine could be out of time

You have described your problem just fine. Have you just changed the needle in your machine? If so, check it is in the right way, you want the flat shank to the back.

The needle has a scarf (scoop out) at the back - if it is facing to the front then the rotary hook (bit that goes around the bobbin and catches the top thread) can't catch the needle thread behind the needle.

Also check needle is fully up into the housing, this could also cause problem.

I'd suggest that you visit www.sewingabout.com and check out the pages on general sewing machine use, care and threading up, lots of helpful pictures and information which may be of assistance to you.

If it isn't your needle backwards (very easy to get wrong, happens all the time), then the timing could be out, which isn't so easy, but as its new I'd be very suprised if this was the fault. Just check needle, make sure top and bottom threads are threaded correctly and have another go. Also, remember to turn flywheel towards you.

First please double check that the flywheel clutch in engaged and not in bobbin winding mode, ie the inner knob is locked by holding outer flywheel and turning inner wheel away from you.

If you remove the needle plate and bobbin cover and turn the flywheel manually can you see the hook rotating at all?

If the needle is going up and down and the rotary hook is not rotating, then my guess will be that the pinon gear down in the free arm area has failed and will need to be replaced. You don't say what model but if it is a star series you should be able to remove the top plate on the free arm by undoing one screw and exposing this area to confirm this. If its a Stella or Lotus it won't be so easy to view. Either way, if its a Swiss made Elna parts are still available and there are serviceman around who can do this repair. If you are in the USA I would suggest you browse www.whitesewingcenter for parts/repair info on Swiss Elnas.

Or try www.sewingpartsonline.com and search by your model number to see the parts available.

Needle in correct? Be sure your bobbin is not in upside down and turning the wrong way. Possibly the hook that the bobbicase fits in/on has been hit by a needle and caused a burr that is catching the thread as it comes around. The burr would have to be polished off or hook replaced. The machine could be slightly out of time also.