Have a brother sawing machine it just humms when i press ladel

Try the following.

Presser foot up.
Rotate handwheel so needle up.
Remove top thread, spool, and bobbin.

Power off

Select straight stitch pattern 2.
Select stitch width 2.5 - needle position middle.
Set tension to 4.

Power on.

1. Press foot pedal.
2. If still knocks, remove needle.
3. Press foot pedal.
4. If still knocks, move bobbin winding spindle all the way right and back all the way left.
5. Press foot pedal.
6. If still knock, remove bobbin case (pg 47 in manual)
7. Press foot pedal.
8. if here and still knock... not sure what it is.

https://download.brother.com/welcome/doch100101/xm2701_2800om03enes.pdf

On the hand wheel there is the lock that is used to stop and start the needle from being used. This is necessary for refilling the bobbin with thread. If the hand wheel doesn't make the needle work then you will need to do some minor adjustment.
1. On the hand wheel find a small screw and loosen it until it is just about ready to remove.
2. Now tighten the hand wheel.
3. Tighten the small screw again.
It should be ready to use now.

My brother XL-3030 will not sew, the light comes on but the machines does not engage to sew when you press the foot pedal. Plus the led screen is blank. Is it the internal computer or the power cord?

Your answer is here. Nothing is wrong.. just operator error. you pressed the "start" button while the foot pedal is connected. Press the pedal instead.

http://welcome.solutions.brother.com/BSC/public/us/us/en/faq/faqh/000000/000000/000066/faqh000066_000.html?reg=us&c=us&lang=en&prod=hf_cs6000btieus&Cat=56

the brother bobbin number is SA 155 it is only available at a Brother Dealer.

It most likely is your foot pedal. Unplug your foot pedal and start the machine without it. If it works properly without the foot pedal plugged in then your foot pedal needs repaired or replaced. This worked for us with the NX400 machine and I am sure the NX450 is closely similar. Don't bother to buy a Manual if you didn't already get one with the machine. A Service manual and parts manual is best; But just so you know they don't show the error codes unless you are a qualified and authorized repair person for the machines. I got my info from the repair man where my wife buys and repairs her machines. I am an electronic technician and mechanic so I understand how this system works. I will be repairing my wife's machines from now on.

The foot pedal was replace?

If it is not right take the machine and foot pedal back and have another installed.

Test before taking home.

The carbons in the ceramic tube normally break away, you should not have any problem if you have a new foot control,

The timing is set on the lower shaft on the left end. Needle bar rise is 2.5mm. Check your timing belt tension to prevent this in the future.

Hello
Make sure the bobbying is lettinng out the string first and also make sure the dial on the left side of machine is on 6 .when you turn the maching around , looking at the back make sure switch in too your right. Also just unplug the maching could help, my wife just had the same problem...