Hologic DISCOVERY A, Technical Manual

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Discovery QDR Series Technical Manual
5-37
3. Loosen the 2 drum motor mount screws, the idler screw and the outer pulley set
screw. Remove the belts.
4. Install the Filter Drum Alignment Pin (099-0110), small end first, through the
slotted holes and into the small hole at the base plate. If the pin is installed prop-
erly, the drum will not rotate.
5. Install the 150 tooth belt on the back pulley (ensure the belt is positioned under
the idler).
6. Install the 130 tooth belt on the front pulley.
7. Tighten the 2 drum motor mount screws (the motor mount is spring loaded to
seek proper tension).
8. Tighten the idler screw (the idler is spring loaded to seek proper tension).
9. Tighten the outer pulley set screw.
10. Remove the Filter Drum Alignment Pin.
11. Pull the Emergency Stop button.
5.9.3 Stepper Motor Assembly
To remove and replace the Stepper Motor Assembly, refer to Figure 5-18 and follow the
procedure below:
1. Shut down the computer and then turn off the main circuit breaker on the foot end
pedestal.
2. Remove the Aperture Assembly.
3. Remove the drum belts (see procedure above).
4. Remove the stepper motor pulley.
5. Remove and replace the motor (4 flathead Phillips screws).
6. Replace the pulley, use Loctite 222 (540-0100) on the set screw.
7. Refer to the Drum Belts procedure above and replace the belts.
5.9.4 Drum Bearings
To remove and replace the drum bearings, refer to Figure 5-21 and Figure 5-22 and follow
the procedure below: