Discovery MR750w and SIGNA™ Architect T 3.0T System Service Methods
5690002-2EN Revision 4
Object ID: 00000018WIA30E3F030GYZ
Topic ID: id_12373862 Version: 1.19
Date: Oct 11, 2021 3:47:40 PM

LPCA Components Replacement

Prerequisites

Table 1. Personnel requirements
Required persons	Preliminary requirements	Procedure	Finalization
1	Not Applicable	See Procedure Overview	20 minutes

Table 2. Tools and test equipment
Item	Quantity	Effectivity	Part number	Manufacturer
Non-magnetic service tool kit	1	-	5112581	-

Table 3. Replacement parts
Item	Quantity	Effectivity	Part number	Manufacturer
DVMR LPCA (multiple)	1 each	-	See FRU manual	-
LPCA cover (RRx systems)	1 each	-	See FRU manual	-
A-port bezel (RRx systems)	1 each	-	See FRU manual	-
LED and switch harness (RRx systems)	1 each	-	See FRU manual	-
Sub-D plate	1 each	-	See FRU manual	-
Plunger assembly	1 each	-	See FRU manual	-
Cradle latch	1 each	-	See FRU manual	-

Table 4. Safety

DANGER

Strong Magnetic Field

Ferrous materials can become dangerous projectiles in the presence of the magnetic field Produced by the Magnet.

Do not Bring any ferromagnetic tools or equipment into the magnet room.

Warning

Electrical Hazard

Strong voltages are present in or around the LPCA when energized.

Remove power from the LPCA at the pdu. then lockout and tagout the pdu. See the LATEST REVISION OF THE MR Service Safety Manual, PN 5452735, IN THE ONLINE DOCUMENTATION LIBRARY.

About this task

Overview

LPCA FRU procedures and timings:

LPCA cover: procedure timing - 10 minutes
A-port bezel: procedure timing - 30 minutes
LED and switch harness: procedure timing - 20 minutes
Cradle latch: procedure timing - 15 minutes
Sub-D plate: procedure timing - 45 minutes
Plunger: procedure timing - 15 minutes

Topic ID: id_SL2069234-1061821

Removing and Replacing the LPCA Cover

Procedure

At the operator control panel, drive the LPCA and cradle through the magnet bore to within 1 foot (30 cm) from the end of the rear bridge. This should provide enough room to work on the LPCA.

The LPCA will not move if the patient table is disconnected or not at the high limit before LPCA movement.
At the foot of the table, twist or squeeze the cradle release handle to detach the cradle from the LPCA. Pull the cradle by hand to the home position so it is fully retracted onto the patient table.
Undock the patient table and move it away from the magnet.
Remove the four screws on the top of the LPCA cover.

Figure 1. LPCA Cover Screws
Remove the cover.

Note:
To remove the cover, slide it slightly forward and lift the front of the LPCA to clear the hardware, and then slide back and up.
Place the new cover on the LPCA assembly starting at the rear and then the front. Take care to not pinch any of the wires in the rear of the LPCA.
Attach the cover with the four screws.
Re-dock the patient table to drive the LPCA to the home position and reattach to the cradle/patient table. Dock the table by pressing the mechanical docking pedal. If the table is equipped with P-connectors or the GEM coil, engage the electrical dock connector by pressing the middle foot pedal.

Figure 2. Electronic Docking Pedal

Topic ID: id_SL2069243-1061821

A-Port Bezel

Topic ID: id_SL2069244-1061821

Removing A-Port Bezel

Procedure

Remove the LPCA cover (see Removing and Replacing the LPCA Cover).

Notice

PAY CLOSE ATTENTION TO THE ROUTING OF THE BEZEL CABLES BEFORE DISCONNECTING. YOU NEED TO RECREATE THE ROUTING PATTERNS WHEN RECONNECTING THE CABLES.

Behind the A-port bezel, disconnect all cable connections (J1, J2, J4, and J5) from the sub-D (or bulkhead) plate. A 3/16 nut driver is required to remove J1 and J2.

To remove the microphone cable, pull out the silver block attached to the end of the microphone cable from behind the microphone bracket.

Figure 4. Microphone Cable Path
Remove the LEDs from the bezel. Be careful not to disconnect the cable from the LEDs.

Figure 5. Removing LED from LED and Switch Harness

Note:
Reuse the LEDs from the old A-port bezel.
To remove the A-port bezel from the sub-D plate, remove two brass pan head screws (left and right) from the plate bracket at the rear of the A-port bezel.

Figure 6. A-Port Bezel Screws

Topic ID: id_SL2069247-1061821

Replacing A-Port Bezel

Procedure

DANGER

Strong Magnetic Field!

Ferrous materials can become dangerous projectiles in the presence of the magnetic field Produced by the Magnet.

Do not Bring any ferromagnetic tools or equipment into the magnet room. Insert leds into bezel sockets outside of magnet room if possible.

To replace the LED into the socket of the new A-port bezel, use a small slotted screwdriver to push the LED into place, making sure the LED is flush with the face of the bezel.

Attach the new bezel to the sub-D plate by replacing the brass pan head screws (left and right). See Figure 6.
To properly reconnect all cables, do the following:
1. Spread the two sections of wire on J2 and feed J1 though the separation.
  
  Figure 8. Bezel Cable Routing – substep a
2. Leave J1 lying straight out, then rotate J2 counter-clockwise as needed until it meets up properly with J2 through the sub-D plate. Push the two connectors together and then secure them using 3/16 inch nuts and a 3/16 inch nut driver.
  
  Figure 9. Bezel Cable Routing – substep b
3. Connect J5 to the N bulkhead adapter on the sub-D plate.
  
  Figure 10. Bezel Cable Routing – substep c
4. Connect J1 to J1, through the sub-D plate. Push the two connectors together and then secure them using 3/16 inch nuts and a 3/16 inch nut driver.
  
  Figure 11. Bezel Cable Routing – substep d
5. Feed J4 between J1 and J5. Then wrap J4 around the front of the sub-D plate, ensuring that it routes below the bezel. Connect J4 to the BNC bulkhead adapter on the top of the sub-D plate.
  
  Figure 12. Bezel Cable Routing – substep e
Verify that the cables are routed and connected as shown in Figure 3.
Replace the microphone cable into the microphone bracket. See Figure 4.
Replace the LPCA cover (see Removing and Replacing the LPCA Cover).

Topic ID: id_SL2070493-1061821

Removing and Replacing LED and Switch Harness

About this task

Systems using the RRx receive chain have both the LED and switch harness.

Procedure

Remove the LPCA cover (see Removing and Replacing the LPCA Cover).

Figure 13. Front of LPCA, LED and Switch Harness Connection Points – RRx Receive Chain
In the middle of the LPCA near the drive belt well, disconnect the LED and switch harness from the cable track A connection.
At the rear of the LPCA, remove the LEDs from the top of the A-port bezel. Be careful not to disconnect the cable from the LEDs.

Figure 14. Rear of LPCA and Switch Harness Connection Points – RRx Receive Chain
Remove all screws holding all three switches.

Switches 1 and 2 are on the front of the LPCA, and switch 3 is in the rear of the LPCA.

Figure 15. Switch Locations
Remove the harness.
Replace the switches, label side visible at front and rear of the LPCA, then to the cable track A connection in the middle, and then reinstall the LEDs (if present).
Replace the LPCA cover (see Removing and Replacing the LPCA Cover).

Topic ID: id_SL2071035-1061821

Removing and Replacing Cradle Latch

Procedure

Remove the LPCA cover (see Removing and Replacing the LPCA Cover).
Remove the four brass slotted head screws at the base of the cradle latch.

Figure 16. LPCA Cradle Latch
On the bottom side of the latch, use a standard head screwdriver to remove the compression spring screw.
To reassemble the new cradle latch:
1. Replace the compression spring screw on the bottom side of the latch.
2. Replace the four brass slotted head screws at the base of the cradle latch.
Replace the LPCA cover (see Removing and Replacing the LPCA Cover).

Topic ID: id_SL2071460-1061821

Removing and Replacing Sub-D (or Bulkhead) Plate

About this task

The sub-D plate contains two components on systems using the RRx receive chain (the A-port bezel and the microphone). To replace the sub-D plate, both components and their respective cable connections must be completely removed.

Procedure

Remove the LPCA cover (see Removing and Replacing the LPCA Cover).

Notice

AFTER DISCONNECTING THE BEZEL CABLE CONNECTIONS, TRY TO LEAVE THE ROUTING OF THE CABLES IN PLACE AS MUCH AS POSSIBLE. THIS WILL HELP SPEED UP THE REPLACEMENT PROCESS. EQUALLY IMPORTANT IS NOT TO DISLODGE, MOVE, OR DISTURB OTHER CABLE CONNECTIONS ASSOCIATED WITH THE SUB-D PLATE, SUCH AS THE J2 CONNECTOR AND MICROPHONE CABLE.

To remove the A-port bezel and all of its cable connections on the top of the sub-D plate, follow the procedure in Removing A-Port Bezel.

Note:

Removal of the adapter connections on the bottom of the sub-D plate is described later in this procedure.

To remove the microphone cable, pull out the silver cable block from behind the microphone bracket. See Figure 4.
After removing and setting aside the A-port bezel and its cables, remove the sub-D plate screws. See Figure 6.
On the bottom of the sub-D plate, remove cable connections, and then use a 16 mm non-ferrous combination wrench and a 3/4 inch non-ferrous combination wrench to remove both bulkhead adapters. See Figure 17.
On the replacement sub-D plate, reattach cable connections and bulkhead adapters on the bottom of the plate.

Figure 17. Bottom of Sub-D (or Bulkhead) Plate
To reattach the sub-D plate to the LPCA assembly, do the following:
1. Leave the microphone cable (silver cable block) lying straight, making sure that it is on top of J1, J4, and J5 and not connected.
  
  Figure 18. Reattaching Sub-D Plate and J2 Connector
2. Position J2 to the right side of the cable track and curl it until the connector is turned 180 degrees. Then locate J2 into its slot on the sub-D plate and move the plate down towards its mounting position while holding J2 in place.
3. Locate the J1 connector into its slot. See Figure 3 and Figure 11.
4. Reattach the four sub-D plate screws. See Figure 6.
To reattach the A-port bezel and its cables, see Step 3 through Step 4.
Replace the microphone cable into the microphone bracket. See Figure 4.
Replace the LPCA cover (see Removing and Replacing the LPCA Cover).

Topic ID: id_SL14737415-1061821

Removing and Replacing Plunger Assembly

Procedure

Remove the LPCA cover (see Removing and Replacing the LPCA Cover).
Remove the three screws securing the plunger assembly to the LPCA base (1,2,3) and remove the plunger assembly.

Figure 19. LPCA Plunger Assembly
Insert replacement plunger assembly.
Replace screws as shown in Figure 2 removed in Step 2.
Replace the LPCA cover (see Removing and Replacing the LPCA Cover).

Topic ID: id_15229475

Finalization

Procedure

Do a test scan to verify system operation (see Check Scan).