How do I unlock the handwheel?

Question edited for clarity.
Question moved to Baby Lock.

If it binds and locks up, you can force it in the direction of travel using the handwheel. Remove the needle and the bobbin and run it full speed for 15 seconds. If it continues to do it, you need to take in for service and more importantly, timing.

Check the bobbin area and make sure there's not a tangle of thread keeping the hook from turning.

Remove the needles. See if the handwheel moves now. Since it's a new machine, consult with the seller.

sounds like someone has taken the hand wheel off at some point.

There is a locking washer inside as well as a shim or two. The locking washer needs to be oriented correctly before you put the knob on and screw it in place.

does the needle go up and down when you turn the handwheel by hand? if so, one of the belts may be slipping - tighten it enough to make it grab.

if the handwheel does not make the needle go up and down, is the handwheel lock for bobbin winding un-locked? if so tighten the handwheel lock inside the handwheel. if the handwheel lock is tightened and the handwheel spins when motor runs the handwheel lock is asembled incorrectly. if this is the case, undo screw in handwhhel lock nut and spin lock nut off machine, then remove pronged washer and turn 1/3 turn and re-install.

scott

most likely, you have a small piece of thread caught between the hook assembly and the bobbin case base. you can try to unlock the machine by holding the position finger with your left hand and turn the handwheel backwards. If it unlocks, use a can of canned air to blow it out.

Unfortunately my experience has been whenever a serger gets "locked up" or "frozen" it requires a trip to the service department or getting a new machine. Best bet call your repairman and tell him what the problem is. You won't be able to fix it yourself.

use 2 large pair of pliers instead of your fingers,goodluck

Depending on the overall thickness of the proposed job, this should be fine provided you bear a few things in mind, and monitor progress.

Use a new size 14 or leather needle, and be prepared to renew needle several times depending on the size of the job........start the sewing by turning the handwheel to create the first stitch and run at low to moderate speed
.....if the machine feels like it is struggling from the outset, do not continue.....
if it runs fine and only starts to labour after a while, the needle will have become blunt...replace it.

For each new seam, start by turning the handwheel manually, just to get things started.....you may also find this helpful at the end of seams for the lock stitch

Also...
The presser foot tension may need to be relaxed a little depending on the overall thickness of the job