Discovery MR750 3.0T System Service Methods
5690009-2EN Revision 4
Object ID: 00000018WIA30DE1130GYZ
Topic ID: id_15271104 Version: 2.8
Date: Oct 11, 2021 8:57:02 PM

Dock Component Replacement

Prerequisites

Table 1. Personnel requirements
Required persons	Preliminary requirements	Procedure	Finalization
2	-	60 minutes for 450/750/450w; 130 minutes for 450w GEM/750w GEM	-

Table 2. Tools and test equipment
Item	Quantity	Effectivity	Part number	Manufacturer
Non-Magnetic Tool Kit	1	-	5112581 or 5113258	-

Table 3. Consumables
Item	Quantity	Effectivity	Part number	Manufacturer
Loctite 242 Threadlocker	(1) 0.5CC Tube	-	-	-
Fish Paper	As needed	-	-	-
Self-locking Cable Tie	As needed	-	46-208758P5	-

Table 4. Replacement parts
Item	Quantity	Effectivity	Part number	Manufacturer
Dock Motor	1	-	See FRU manual	-
SPDT Snap Action Switch	4	-	See FRU manual	-
Dock Pedal Spring	2	-	5448742	-

Table 5. Safety

DANGER

ELECTROCUTION HAZARD!

HIGH VOLTAGE PRESENT.

USE PROPER LOTO PROCEDURES BEFORE servicing or maintaining. See the MR Service Safety Manual, PN 5452735.

Warning

POSSIBLE PERSONAL INJURY!

THIS PROCEDURE REQUIRES movement OF FERROUS MATERIAL IN CLOSE PROXIMITY TO THE MAGNET.

two Field engineers are required at all times.

Warning

Personal injury and equipment damage!

Strong Magnetic Field

When servicing any magnetic equipment, it is critically important that the service engineer consciously plan the path to be taken when moving highly ferrous devices in the magnet environment. The path should be as far from the magnet as practical and avoid high flux-density fields.

Safety Requirements

THE SERVICE PATH MUST ALLOW FOR THE DOCK TO BE MOVED ALONG THE GROUND A DISTANCE EQUAL TO THAT OF THE DISTANCE BETWEEN THE MAGNET AND THE FOOT-END OF THE PATIENT TABLE PRIOR TO BEING LIFTED VERTICALLY. When exiting, move away from the magnet in the most direct manner possible. Except when moving ferrous material to/from its native location on or near the magnet, the static magnetic field in any portion of the service path shall not exceed 200 Gauss

Two (2) MR safety trained personnel must be present at all times when servicing highly ferrous devices in the areas of magnetic fields.

When planning a service path, it is critical that the path be clear and sufficiently wide. Ensure that there are no trip hazards, obstacles, clutter, slippery surfaces or other items even partially restricting the path. If there are portable obstacles in a path, remove them from the area and replace them after the service action is completed. It is required to walk the path prior to beginning service to ensure that there is sufficient space through which to pass for yourself and the object being serviced.

Table 6. Required conditions
Condition	Reference	Effectivity
All persons performing this procedure must complete GE-certified MR safety training.	-	-

Topic ID: id_SL5396266-1061569

Overview

About this task

This document describes how to perform the following procedures:

Dock Cover Removal: Dock Cover Removal
Dock Motor Replacement: Dock Motor Replacement
Dock Switch Removal and Installation: Dock Switch Removal and Installation
Dock Pedal Spring Replacement: Dock Pedal Spring Replacement
Dock Cover Reinstallation: Dock Cover Reinstallation

Topic ID: id_SL3885919-1061569

Dock Cover Removal

Procedure

Warning

Removing the dock cover in the Magnet room can cause personal injury and equipment damage!

Components attached to the dock cover are highly ferrous and strongly attracted to the magnet.

Remove the dock from the magnet room before removing the dock cover. see Dock Removal and Reinstallation.

Remove the dock from the magnet room. See Dock Removal and Reinstallation.

Remove four bolts (two on each side) to unfasten the dock cover from the dock base.

Figure 1. Dock Cover and Dock Base
While removing the dock cover, disconnect the switch connector.

Figure 2. Switch Connector
Carefully remove the dock cover from the dock base and then turn the dock cover upside down.

Note:
Be careful not to scratch the top of the cover. Lay down a cloth before putting the cover on the floor.

Topic ID: id_SL1708560-1061569

Dock Motor Replacement

Topic ID: id_SL5396271-1061569

Dock Motor Removal

Procedure

Warning

Removing the dock cover in the Magnet room can cause personal injury and equipment damage!

Components attached to the dock cover are highly ferrous and strongly attracted to the magnet.

Remove the dock from the magnet room before removing the dock cover. see Dock Removal and Reinstallation.

Remove the dock from the magnet room. See Dock Removal and Reinstallation.

Remove the dock cover. See Dock Cover Removal.
Disconnect the dock motor power cable, terminal wires, and ground wire.

Figure 3. Power Cable, Terminal, and Ground Wires
Remove four screws (two on each side) from the dock motor mount plate.

Figure 4. Dock Motor Mount Plate Screws
Remove the dock motor.

Notice

Do not discard the old dock motor. You will reuse the dock gearbox shaft.

See Dock Motor Installation for instructions on how to reuse the coupling and install the new dock motor.

Topic ID: id_SL5396257-1061569

Dock Motor Installation

Procedure

Remove the e-clip from the end of the dock gearbox shaft on the old dock motor using the blade of a slotted screwdriver. Secure the e-clip during removal to prevent the clip from flying away when pressured.

Figure 5. Old Dock Motor, Gearbox Shaft, and E-Clip
Slide the dock gearbox shaft and key out of the dock motor and set it aside. Remove four screws and mounting plate.

Figure 6. Dock Gearbox Shaft
Apply Loctite 242 on the hex screws of the new motor.

Figure 7. Dock Motor, Mount Plate, and Screws
Position the mount plate on the dock motor and fasten with the four screws.

Warning

Fire Hazard!

The dock motor wires can catch fire, if not tie-wrapped properly.

All the dock motor cable wires must be properly tie-wrapped.

Tie-wrap the cables as shown in Figure 8.

If replacing the shaft only, apply a small amount of anti-seize (from shaft assembly FRU kit) to the shaft key. If the complete dock motor assembly is being replaced, anti-seize is not required.
Assemble the drive coupling on new shaft, then slide the new gearbox shaft, with spring and key, into the motor and replace the e-clip. See Figure 6.
Apply Loctite 242 on the four mount plate screws, position the dock motor onto the dock cover, and then reattach the dock motor. See Figure 4.

Reconnect the terminal wires, ground wire, and power cable to original terminal strips. See Figure 3 and the following illustration.

Reconnect the switch connector.
Reinstall the dock cover. See Dock Cover Reinstallation.
Reinstall the dock. See Dock Removal and Reinstallation.

1	Ground stud	6	Dock motor
2	Ground wire from dock motor (green)	7	Dock motor cable connectors for position 1
3	Terminal block	8	Dock motor cable connectors for position 2
4	Black wire from dock motor (black)	9	Dock motor cable
5	White wire from dock motor (white)

Topic ID: id_SL3885921-1061569

Dock Switch Removal and Installation

About this task

Switch 1 is located in the bottom casting. Switches 2, 3, and 4 are located in the dock cover.

Procedure

Warning

Removing the dock cover in the Magnet room can cause personal injury and equipment damage!

Components attached to the dock cover are highly ferrous and strongly attracted to the magnet.

Remove the dock from the magnet room before removing the dock cover. see Dock Removal and Reinstallation.

Remove the dock from the magnet room. See Dock Removal and Reinstallation.

Remove the dock cover. See Dock Cover Removal.
Remove the defective switch as required. Note the wire attachment locations on the switch terminals.
When replacing switch 1 (inside the bottom casting):
1. Place a square of fish paper between the switch and the mounting wall.
2. Add Loctite 242 to each screw before replacing it.
3. Tighten each screw until the screw stops without applying torque. Then turn the screw 30 degrees.
When replacing switches 2, 3, or 4:
1. Add Loctite 242 to each screw before replacing it.
2. Push the switch toward the respective shaft while tightening the screws.
  
  Tighten each screw until the screw stops without applying torque. Then turn the screw 30 degrees.
3. After installation, verify that all three switches activate and deactivate (an audible click should be heard) while cycling the shaft, in and out, at least three times (rotate the shaft approximately 120° for each cycle).

Reconnect the wires to the switch terminals.

Table 7. Wire Chart for Switch Terminals
One End					Other End
Pair No.	Color	Position	Terminal			Strip Range	Term 511A590P	Mark
1	BLU	1	AMP 66506–3			5.8	27	SW4 NO
1	BLK	3	AMP 66506–3			5.8	27	SW4 COM
2	RED	4	AMP 66506–3			4.3	105	SW1 NO
2	BLK	12	AMP 66506–3			4.3	105	SW1 COM
3	GRN	5	AMP 66506–3			5.8	27	SW3 NO
3	BLK	13	AMP 66506–3			5.8	27	SW3 COM
4	WHT	6	AMP 66506–3			5.8	27	SW2 NO
4	BLK	14	AMP 66506–3			5.8	27	SW2 COM
		7	AMP 66506–3	Jump to Position 15
		15	AMP 66506–3	Jump to Position 7

For more information, refer to the block diagrams for the site’s MR system.

Reinstall the dock cover. See Dock Cover Reinstallation.
Reinstall the dock. See Dock Removal and Reinstallation.

Topic ID: id_SL5396272-1061569

Dock Pedal Spring Replacement

Procedure

Warning

Removing the dock cover in the Magnet room can cause personal injury and equipment damage!

Components attached to the dock cover are highly ferrous and strongly attracted to the magnet.

Remove the dock from the magnet room before removing the dock cover. see Dock Removal and Reinstallation.

Remove the dock from the magnet room. See Dock Removal and Reinstallation.

Remove the dock cover. See Dock Cover Removal.

Remove both of the old pedal springs from the dock pedals. The springs are held in place only by spring tension. Pull up on one end of each spring to remove them from the pedal assemblies.


1	Dock pedal spring	3	Dock pedal assembly without spring
2	Dock pedal assembly with spring in place	4	Pull up on spring end to remove spring

Notice

The dock pedal spring will break if you apply too much force to it while inserting it into the pedals. Insert the spring into only one pedal at a time.

Do not bend the spring to insert it into both pedals at the same time.

Grasp one end of the dock pedal spring. Insert the end of the spring into the hole at the end of one of the dock pedals.


1	Dock pedal assembly
2	Hole for dock pedal spring

Grasp the other end of the dock pedal spring (at approximately 1 inch (25 mm) from the free end of the spring), and gently insert it into the hole at the end of the other dock pedal. It is easier to insert the spring into the pedal if you press down on the pedal.

Figure 14. Dock Pedal Spring Grasp Point
Repeat Step 4 and Step 5 for the other pedal spring.
Reinstall the dock cover. See Dock Cover Reinstallation.
Reinstall the dock. See Dock Removal and Reinstallation.

1	Dock pedal spring
2	Grasp one end of the spring and insert it into the hole at the end of one dock pedal.
3	Grasp the end of the spring approximately 1 inch (25 mm) from the end of the spring, and then gently insert the end into the hole in the other dock pedal.
4	Position of the dock pedal spring after installation

Topic ID: id_SL3885946-1061569

Dock Cover Reinstallation

Procedure

Reattach the switch connector. See Figure 2.
Place the dock cover onto the dock base and reattach the dock cover bolts. See Figure 1.
Reinstall the dock. See Dock Removal and Reinstallation.

Topic ID: id_15362455

Finalization

Perform Dock Adjustments and Dock Hardware Adjustments as necessary.
Ensure the motor is functioning properly when docking the patient table and verify that lowering the table results in automatic retraction of the LPCA into the bridge.