Jugs pitching machine bottom wheel not working

Question edited for clarity.
Question moved from Cars and Trucks.

Put it together and run a bucket of balls through it. If it holds, you are fine. If not, spares are readily available.

https://www.google.com/search?q=jugs+pitching+machine+parts

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Check for a loose belt.

Pretty sure you can take it to a tire shop and get that done

Take off the cover and make sure the wire is connected to the knob and check the wire maybe it's exposed an not working properly

What's wrong with it need more info

Just had this happen on my machine. Opened up the control box and found center disc capcitor was loose from cold solder joint. However we also found the hot lead for the motor at the wiring block on the circuit board had a cracked solder joint. Simply reheated with solder iron and applied little extra solder and it working again.

Look for stripped wires that could be your problem if you find any tape them up with electrical tape

pull off the wheel and run the machine. you will be able to see if the hub is out off balance. if it spins true the you have a rim or tire out. this can be fixed by having a tire shop balance it for you or call Jugs and get a complete replacement,tire and rim ,shipped mounted and balanced.
it is very unlikely that the motor shaft is damaged unless it was droped trying to load it into a truck.
it most like;y is the tire and rim that is out

It could possibly be one of the bearings starting to go, is the machine well used or new?

it it something to do with the wiring