I was given a Necchi 3102 sewing machine

Basic Tips for All

1. Always turn the handwheel TOWARDS you (counter clockwise) as turning it in the opposite direction (away from you, clockwise) may knock the timing out requiring repair from a service center.
2. Always be sure your presser foot is in the DOWN position before sewing. Sewing with the presser foot in the up position will cause your thread to tangle and your bobbin to jam.
3. Change needles regularly (after 16 hours of use) as dull/weak needles can cause damage to your machine and fabric. Only use SINGER needles on your SINGER sewing machine.
4. Always be sure you are using the correct bobbin for your machine. Class 66, Class 15 and Class 15J bobbins look very similar. However, using the incorrect bobbin class in your machine can cause damage.

How do I thread my 3/4 thread serger? (14SH654, 14ET754, 14SH764, 14CG754)
Q.
How do I thread my 2/3/4/5 thread serger? (14T967, 14T968, 14T957)
Why is my electronic machine beeping? Why won't my machine sew? Why will my machine start to sew then stop?
Q.
How do I sew denim and heavy fabrics?
Q.
Why is my bobbin not winding evenly?
Q.
Why won't my machine pick up the bobbin thread?
Q.
Why is my machine skipping stitches?
Q.
Why is the thread looping/bunching under my fabric?
Q.
Why is the thread looping/bunching on top of my fabric?
Q.
Why doesn't my stitch pattern match what is on my machine?
Q.
How often should I oil my machine?
Q.
What types of thread should I use?
Q.
I can't see the take-up lever? ,,,,,,

try this link for a manual and the information should be in it Necchi 3101 FA 3102 FB Instruction Manual

It may not have seized there may be a very small piece of thread jammed in the raceway area, you need to take the bobbin case and the raceway out to check

http://www.sew4less.com/index.php
I don't know if the link will work for the bobbin case, if it doesn't
go to sew4less.com
Bobbin Case # 52237 NB, Click for model info.
Product #: 4754

Price: $ 19.95


Bobbin Case # 52237 NB, No backlash type.
A bobbin case, also known as a bobbin holder or bobbin shuttle, holds the bobbin that is filled with thread.
Each machine has a specific bobbin case. # 52237NB
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here are is a site that have manual
http://www.sewingpartsonline.com/

Go to this website
http://www.singerco.com/accessories/instruction-manuals/search, type in "W955" and click "Search", its there to download for free.

Many Singer and White manuals are available from the Singer site.

Not your machine number but maybe this is close.

http://www.sewusa.com/Threading_Diagrams/Threading_Pages/Necchi_Sewing_Machine_Threading/Necchi_3537_threading_Diagram.htm

Are you sure it's a screw type knob and not a push pull button type?

Ok which is it? A Singer or a Necchi?

If it is a Singer or a machine like the one picture here.... slide the grey metal plate toward you. You'll see the "drop in bobbin" Look for a little lever or button that will lift the bobbin up so you can get it out.

Ensure the bobbin thread is mounted on correctly and using your right hand turn the gear that makes the needle go up and down until it catches the thread.

Check the thread coming out from the bobbins maybe on reverse side,also check the bobbins tension adjust it there is a small adjusting screw.Check also the needle alignment lastly check the upper tension from the tension regulator knob,tension adjustment is depend on the fabrics that you sew.