WONT STITCH DOESNT STITCH RIGHT

If it doesnt bring bottom thread to top then the hook is not catching the top thread. I assume your able to bring bottom thread to top?

Bring bottom thread to top, place sample fabric under pesser foot, lower foot, then hold both top and bottom threads in left hand and manually turn handwheel with right hand and see if will stitch.

Dropped stitch(s) implies the top thread is not being wrapped around the bobbin. The rotary hook must catch the top thread as the needle rises, pull additional thread into and around the bobbin and release the top thread. Then the takeup arm pulls the extra top thread from underneath the bobbin and sets the stitch to the selected tension.

If with no fabric it brings bottom thread to top then it's not likely a timing issue but rather an interference or tension problem. Test top thread tension... foot up is no tension, foot down is selected tension and should be noticeable by simply pulling on the top thread and note the difference between foot up vs foot down.

Comment below for further assistance.

How long since it's been thoroughly cleaned and oiled? Sounds like it is seizing due to old oil that has dried.

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

Quite possibly the machine has been knocked out of time. May need to be taken for service.

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The stitch control unit is most likely seized due to dried oil.

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

It was working now it seems to be frozen the needle part wont move

How can fix stuck needle bar on my Bernina 730

Find the pivot point and oil it.

Do you chose the right spool and put it the right side up?

when a part on the sewing machine does not respond like it's suppose to ,,then it would be a good idea to have the sewing machine checked

try changing the needle or is the needle in correctly
check to see if the thread has come off the thread take up lever

Rolled hem would be one needle and two loopers, is this what you meant?

Make sure you move the blade to right so that you are cutting wider than the stitch being formed, you want the fabric to roll to the underside inside the stitch.

I would set top looper tension to 3 and bottom looper tension to 6 first off (needle at five, normal tension) first off and test serge with the stitch length at normal 2 or so, so you can see if the fabric is rolling under for you. There is proabably a stitch finger in the throat that you need to change too, sometimes its on the foot, (change with a screwdriver) and sometimes just a finger down on the needle plate.

Then adjust the two looper tensions making lower thread nestle up against the needle on the bottom of the stitch, and the top looper thread wrapping right over to bottom as well. Once this is happening, then turn stitch length down to close up the stitches.

It does depend on the weight of fabric too, and if you want to seam curves.

I find its best done with wooly overlock thread on top looper to "fill" in the overlocking appearance and fully cover the fabric.

I hope this is of help, if the tensions just wont behave then one of them might be faulty and machine need a service, I get mine done at least every 2 years to keep timing and tensions right.

timing is off, must be taken to a bernna dealer or you can ups to me