• Topic ID: id_12373940
  • Version: 1.12
  • Date: Dec 16, 2019 2:22:43 PM

DTRSW and Preamp Combiner Replacement

Prerequisites

Table 1 Personnel requirements
Required persons Preliminary requirements Procedure Finalization
1 Not Applicable 30 minutes 30 minutes
Table 2 Tools and test equipment
Item Quantity Effectivity Part number Manufacturer
Non-magnetic Phillips Screwdriver 1 - - -
Basic Hand Tool Set 1 - - -
Table 3 Replacement parts
Item Quantity Effectivity Part number Manufacturer
Dual Drive Transmit Receive Switch 1 -

See FRU Manual

 -
Preamp Combiner 1 -

See FRU Manual

 -
Table 4 Safety
  • warning
  • Shock Hazard!
  • High Bias voltages are present at the PREAMP Combiner during normal operation.
  • Remove power. Perform LOTO on the pdm-rf power for the system before accessing the PREAMP Combiner. See the “mr service safety manual,” pn 5452735.
  • caution
  • Strong Magnetic Field!
  • The module has no ferrous material and will not be attracted to the magnet, but the eddy currents set up by the strong magnetic field can make it very hard for one person to handle.
  • When removing and/or replacing the DTRSW on the side of the magnet, plan a path for the module that is as far away from the magnet as possible.

Overview

This procedure includes the following FRU replacement procedures:

  • Dual drive transmit receive switch (DTRSW). Note that the DTRSW for MR750 is different from other products like MR750w and Signa Architect. Refer to the FRU Manual for the correct part number.

  • Preamp combiner

Removing DTRSW or Preamp Combiner

Procedure

  1. Perform LOTO on the PDM-RF power for the system. See the MR Service Safety Manual, PN 5452735.
  2. Disconnect the cables connected to the DTRSW, as follows:

    • If you replace the DTRSW, remove all cables.

    • If you replace the preamp combiner, remove cables from J9, J10, J11, and the Hart ID connector on preamp combiner.

    Figure 1. DTRSW Cable Connections (RRx)

  3. To replace a defective preamp combiner, remove the 4 screws attaching it to the DTRSW.
  4. If you are replacing the DTRSW, remove the preamp combiner first as shown in Step 3. Remove the 4 screws holding the DTRSW to the outside of the magnet.
  5. If you are replacing the DTRSW, remove the preamp combiner and reinstall it on the new DTRSW.
    • caution
    • Strong Magnetic Field!
    • The module has no ferrous material and is not attracted to the magnet, but eddy currents set up by the strong magnetic field interacting with the DTRSW can make it very hard for one person to handle.
    • When removing and/or replacing the DTRSW, plan a path for the module that is as far away from the magnet as possible.
  6. While carrying any module out of the magnet room, stay as far away from the magnet as possible.

Installing DTRSW or Preamp Combiner

Procedure

  1. While carrying any module into the magnet room, stay as far away from the magnet as possible.
    • caution
    • Strong Magnetic Field!
    • The module has no ferrous material and is not attracted to the magnet, but eddy currents set up by the strong magnetic field interacting with the DTRSW can make it very hard for one person to handle.
    • When removing and/or replacing the DTRSW, plan a path for the module that is as far away from the magnet as possible.
  2. Secure the module, as follows:

    • For the DTRSW, secure the module to the magnet by tightening the four screws.

    • For the preamp combiner, secure the module to the DTRSW by tightening the four nuts.

  3. Connect all cables that were previously removed. See Figure 1.

Finalization

Procedure

  1. Replace the side covers.
  2. Remove LOTO from the PDM-RF power for the system. See MR Service Safety Manual, PN 5452735.
  3. Perform TR Dynamic Disable Calibration.
  4. If hardware was replaced, perform System gain calibration for body.
  5. Perform a body SNR test.
  6. Perform SaveInfo to save new calibration values.
  7. Complete a body and head test scan to make sure the system is functional.