The bobbin thread will not come up

SOURCE: I have a Brother SE-270D

its the problem of the timing belt in your machine its extra loosen or extra tightned or is slightly came out of its position or finally broken.
as the machine is proper just missing the proper speed as it should be .
it is running continuosly as you stated.
check the timing belt and make it proper if its worn out and needs replacement this is how its done

There is an adjusting screw on the right side of the machine head. Follow the motor bracket to the machine head and loosen that big old screw or bolt which will raise or lower the motor giving you slack to remove or replace the belt.

feel free for further queries
thanks

SOURCE: Babylock sewing machine, upper thread is bunching

the tension is wronge has the lower bobbin case been unwound and refilled)(check that this is threaded right as well)

SOURCE: NEEDLE WON'T PICK UP BOBBIN THREAD

im not!
it needs a good service the timeing has sliped out a little, nothing more that that,,,see its not a lost cause just yet

Testimonial: "Thanks! I was hoping to avoid paying for a fix, but it looks like I have to **** it up. So much for being thrifty and restyling my clothes."

SOURCE: bottom thread too loose; tried

Check for correct bottom thread tension.
It's provided by a flat spring on the bobbin holder.
When the bobbin is correctly installed, pulling on the thread
should meet with slight resistance, and the bobbin should spin without
trying to jump out of the bobbin holder.

SOURCE: Needle won't pick up bobbin thread. Has been

Most of the time it is because the needle was inserted with the flat side facing you instead of away from you. And for the heck of it, put in a different needle, there may have been a burr or some defect on your new needle. Other than that, it could be your timing.