If it's an older mechanical machine, most likely the old oil has dried and is preventing the parts from moving like they should. It's fixable if you have plenty of patience, elbow grease, good quality oil, and heat.
Of course, you could always take it for service and have it thoroughly checked out and adjusted, if needed.
Wheel on right side that controls the needle up and down is very tight...
You can try searching for:
Make Model parts diagram
However, you may need to take it for service. Even if you are able to get it back together, there may be some pieces that need replacement to make it operate correctly.