Figure 5-8. C-Arm R Frus (Inside View) - Hologic QDR 4500 Technical Manual

C-Arm R Belt
C-Arm R
Encoder Belt

Figure 5-8. C-Arm R FRUs (Inside View)

3. Remove the belt from the motor pulleys. Access the pulleys from the left side of the
Scanner looking under the C-arm (see Figure 5-8).
4. Remove the arm R encoder cable.
5. Remove the Motor Controller board ribbon cable and snake the cable through the access
hole.
6. Remove the entire arm R motor assembly bracket with motor, board and encoder (four
7/16" bolts).
7. Remove the encoder and pulley assembly (2 Phillips screws), and the encoder belt.
8. If replacing the motor or gearcase, remove the four Allen bolts, and nuts, holding them.
If replacing the gearcase, install the pulley from the old gearcase on the new gearcase.
Then, replace the motor and gear case assembly making sure to align the gasket
correctly. Snug the Allen bolts but don't over tighten.
9. If replacing the encoder, remove the hose clamp fastener holding the encoder to the belt
drive and remove the encoder from the bracket assembly. Then, replace the encoder on
the bracket, install the tubing but do not attach the clamp.
10. Replace the arm R motor assembly bracket with motor, board and encoder (four 7/16"
bolts).
11. Replace the cables, and replace the belt on the motor pulleys. Be sure to restore the
cable shield and ground strap terminations.
12. Replace the belt bracket, and loosen the belt tension block (two 1/4" bolts).
13. Adjust the tension nut so that the spring is compressed to 7/8" from the inside of one
washer to the inside of the other washer.
14. Tighten the tension block bolts.
15. Perform the MOTOR$AR calibration procedure.
Section 5 - Remove & Replace
5-17