Microscope Base with Stage and 4 Place Turret - No Head or Electronics

There is no brand or model number on this.  The turret works fine, the stage works fine and the course up and down movement works fine but the fine up and down movement doesn't work. The knob turns but it doesn't move the stage up or down.  Please look at the pictures closely as everything that is included is shown in the pictures.

L3-5

fdk 80817228