Super manual it contains all the things you need to service your Marantz 2100.
Text excerpt from page 25 (click to view)
4. Turn the drive gear to the indicated by arrow fully.
6. Push the 1st lens frame unit to the indicated by arrow from lens side, and then remove the unit of 1st lens frame/2nd lens frame move unit from the drive/direct frame unit.
5. Push the drive unit to the indicated by arrow from lens side, and then remove the unit of drive/direct frame unit, 1st lens frame/2nd lens frame move unit from the fixed frame unit.