track ball not working

What happens when you try moving the wheels manually?

Take the retainer and ball out underneath is two wheels one tracks the ball vertically and the other horizontally. Are you able to move the pointer on the screen up and down and left to right? If not then the sensor unit may have been damaged Macintosh PowerBook 165c Trackball Replacement. Finding a replacement part is getting difficult!

Hopefully the rubber wheels are just gunked up and the fall didn’t damage anything. Use fo 85% or better isopropyl alcohol using cotton swabs (Q-Tip) slowly rotating the wheel rubbing off the junk going across the face inline with the axle. You may need a tweeter to picket the tangle on the axle.