• Discovery MR750 3.0T System Service Methods
  • 5690009-2EN Revision 4
  • Object ID: 00000018WIA30AFD030GYZ
  • Topic ID: id_12374931 Version: 1.5
  • Date: Feb 3, 2022 2:30:26 PM

Gradient Filter Replacement

Prerequisites

Personnel requirements
Required personsPreliminary requirementsProcedureFinalization
1Not Applicable30 minutesNot Applicable
Tools and test equipment
ItemQuantityEffectivityPart numberManufacturer
Digital volt meter (DVM) with alligator clip leads1---
Non-ferrous tool kit1-

-
Replacement parts
ItemQuantityEffectivityPart numberManufacturer
Gen1 Gradient Filter Assembly (RoHS)1-5166619-50-
Table 1. Safety

About this task

Overview

The gradient filter attaches to the secondary pen wall (SPW) from the equipment room. The thumbscrews on the filter attach to PEM nuts on the SPW.

Topic ID: id_SL2018500-1062451

Removing GEN1 Gradient Filter

Procedure

  1. Perform LOTO on the PGR cabinet. Refer to the Applying LOTO - ISC procedure.
  2. From the scan room side of the gradient filter, remove the plastic gradient filter terminal covers.
    Figure 1. Gradient Filter Assembly Gen1
    Note:

    Two wrench technique: Use two wrenches when removing the cables from the gradient input/output connectors on each side of the SPW. One wrench prevents the post from turning, while the other loosens the nut. If you try to loosen the nut with only one wrench, the post itself could turn and damage the gradient filter.

  3. Remove the cables attached to the terminals in the scan room.
  4. From the equipment room side of the gradient filter, remove the plastic gradient filter terminal covers and remove the terminal cables. Use the two wrench technique to remove the cables.
  5. While in the equipment room at the SPW, remove the screws securing the gradient filter assembly to the SPW panel.

    Remove the gradient filter and set aside.

    Figure 2. Gradient Filter Thumbscrews
Topic ID: id_SL2018510-1062451

Installing GEN1 Gradient Filter

Procedure

  1. Lift the gradient filter onto the guide pins on the SPW and tighten the thumb screws. When done, use a screwdriver to tighten.
  2. Attach the cables to the gradient filter connections on both sides of the filter. Start with the GND, Z-axis, Y-axis, and X-axis cables and ground wires. Snugly tighten each cap nut to attach the correct axis cable to the correct gradient filter connection. The lug connections between axis and polarities should not be touching.
    Figure 3. Gradient Terminals
    Note:

    Red cable indicates positive (+) wires, black cables indicate negative (-) wires.

    Two wrench technique: Use two wrenches when attaching the cables from the gradient input/output connectors on each side of the SPW. One wrench prevents the post from turning, while the other tightens the nut. If you try to tighten the nut with only one wrench, the post itself could turn and damage the gradient filter.

    Note:

    Make sure to tighten each cable as you attach it, because you cannot reach all cables after attaching them.

  3. Tighten the cap nuts and verify that nuts are not loose.

    Verify that all connections are tight, correct, and not touching each other. Make sure each screw is fixed, each nut is tight, and each cable is not detached from terminal.

    Figure 4. Cables Connected
  4. Replace the plastic gradient filter terminal covers.
  5. Remove LOTO from the PGR cabinet. Refer to the Removing LOTO - ISC procedure.