• Discovery MR750w and SIGNA™ Architect T 3.0T System Service Methods
  • 5690002-2EN Revision 4
  • Object ID: 00000018WIA303AF030GYZ
  • Topic ID: id_12373888 Version: 1.18
  • Date: Oct 11, 2021 3:47:40 PM

PAC and SRI-4 Replacement

Prerequisites

Table 1. Personnel requirements
Required personsPreliminary requirementsProcedureFinalization
1Not Applicable30 mins. for PAC; 45 mins. for SRI30 minutes
Table 2. Tools and test equipment
ItemQuantityEffectivityPart numberManufacturer
Nonmagnetic service tool kit1-

5112581

-
Table 3. Replacement parts
ItemQuantityEffectivityPart numberManufacturer
PAC-2BV FRU1---
PAC-5 FRU1---
Table 4. Safety

About this task

Overview

This procedure explains replacement of the physiological acquisition controller (PAC) assembly and the scan room interface (SRI-4) on a fixed site system.

The systems may have either a PAC-2BV or a PAC-5. The PAC-5 is backward compatible with the PAC-2BV. There is no impact with PAC hardware configuration in Guided Install.

Topic ID: id_SL1932516-1093049

Removal of the PAC

Procedure

  1. Perform LOTO on the RF amplifier and PEN cabinet. See the MR Service Safety Manual, PN 5452735.
  2. The PAC is behind the left side middle cover.
    Figure 1. PAC Location
  3. Disconnect all cables from the I/O panel except the white PPG cable, which is permanently attached.
    1. Remove the left side covers to access the PAC. See Side and Top Cover Removal and Installation.
    2. Carefully pass the PPG cable through the opening in the left side middle cover. Avoid damage to the cable while removing the cover.
    Figure 2. General Location of PAC and SRI (RRx Systems)
  4. Disconnect all cables attached to the side of the PAC.
  5. Remove the screws securing the PAC and PAC interface to the electronic rack.
Topic ID: id_SL3841231-1093049

Installation of the New PAC

Procedure

  1. Note:

    If replacing a PAC-2BV with a PAC-5, use existing cables. Do not order a PAC-5 Y cable.

    Place the PAC in the proper location and install it in reverse order from how it was removed.
  2. Attach all previously removed cables to the replacement PAC.
  3. Replace all previously removed covers and enclosure trim panels.
  4. Check the alignment of the PAC with the enclosure in all three planes.

    • There are adjustment screws that allow for adjustment up/down, left/right, and in/out.

    • Adjust the PAC I/O panel so that it lines up with the slot in the enclosure in the left/right and up/down plane, and adjust it in/out so the gap between the I/O panel and the enclosure is less than 1 mm.

    Figure 3. PAC Alignment (RRx Systems)
  5. Remove LOTO and restore power to the system. See the MR Service Safety Manual, PN 5452735.
Topic ID: id_SL2857025-1093049

Removal of the SRI

Procedure

  1. Perform LOTO on the PGR PDU/gradient subsystem. See the MR Service Safety Manual, PN 5452735.
  2. The SRI is located under the left side of the magnet enclosure:

    • Toward the rear of the magnet. See Figure 2.

  3. Remove the left side covers and expose the SRI. See Side Cover Removal and Installation.
  4. Remove the temperature sensor box attached to the SRI. (It will be reinstalled on the replacement SRI.)
  5. Disconnect the cables attached to the SRI.
    Figure 4. SRI Cable Map
  6. Remove the four screws securing the SRI to the electronics rack. Unstrap and remove the SRI.
  7. Remove the straps from the SRI. They will be used when installing the new SRI.
Topic ID: id_SL2857029-1093049

Installation of the New SRI

Procedure

  1. Place the new SRI in the proper location, and install in the reverse order of how it was removed.
  2. Mount the removed temperature sensor box on the replacement SRI.
  3. Reconnect the cables and replace the enclosure panels.
  4. Remove LOTO and restore power to the system. See the MR Service Safety Manual, PN 5452735.
Topic ID: id_15238359

Finalization

Procedure

  1. Perform a TPS reset.
  2. Confirm that the reported problem has been resolved by running PAC or SRI diagnostics. In Service Methods, instructions for these diagnostics can be found in Troubleshooting > Diagnostics > Hardware Location > Magnet Room > PAC Diagnostic Tests and SRI Functional Diagnostics.
  3. Perform a Check Scan.