• Topic ID: id_15460911
  • Version: 3.0
  • Date: Nov 27, 2020 2:13:35 AM

Axial Encoder Assembly Replacement

Prerequisites

Overview

This replacement procedure defines the replacement process for the axial encoder.

Procedure

  1. Remove gantry right side cover.

    Refer to Replacement > Gantry > Enclosure > (Cover Removal Procedures).

  2. Turn OFF the Axial Drive and HVDC switches on the gantry’s Service Switch Panel.
  3. Rotate the gantry to place the 48V Power supply behind the service switch panel. This places the tube at about the 10 o'clock position for easier access to the encoder.
  4. Turn OFF the 120 VAC switch on the gantry’s Service Switch Panel.
  5. Remove the gantry left side cover, top covers and front cover.
  6. Disconnect the Encoder DB-9 pin connect from the gantry harness on the gantry frame above the encoder. See Figure 1.

    Figure 1. Encoder DB 9-Pin Connect

  7. Carefully cut cable ties as necessary.
  8. Using the 8 mm hex key, remove the shoulder bolt on which the encoder assembly pivots.
    note:

    Do not remove grease from shoulder bolt. Some grease is necessary for free movement of assembly. If necessary wipe some grease from the inside of the old assembly and re-apply to shoulder bolt.

    If necessary, encoder shoulder bolt and grease can be ordered. Refer to Section 3.3 Replacement Parts.

    Figure 2. Encoder pivot/mount

  9. Install the new encoder assembly, route and connect the cable.
    1. Slide shoulder bolt into encoder assembly so the threads are sticking out the back.
    2. Apply a minimal amount of Loctite 242 to the tip of the shoulder bolt threads. This is to insure that the Loctite does NOT wick out onto the shoulder of the bolt and mix with the grease.
    3. Position the assembly and thread the bolt into the stationary base frame.
  10. Torque the mount bolt to the following:
  11. Replace any cable ties removed during part removal.
  12. Perform the Resetting the C-Pulse procedure.
  13. Install the gantry front, top and left side covers.

    Refer to Replacement > Gantry > Enclosure > (Cover Removal Procedures).

  14. Enable 120 VAC HVDC and Axial Drive service switches from the service switch panel. Press the table drives enable button on the lower right corner of the service switch panel.
  15. Install the gantry right side cover.

Finalization

  1. Perform a System Scanning Test from the Functional Checks menu of the service manual to ensure system operation.