Backplane Replacement - Merc40

Prerequisites

Table 2. Tools and test equipment
Item	Quantity	Effectivity	Part number	Manufacturer
FE torque wrench kit	1	-	46-268445G1 or 5135228 or equivalent	-
5 and 6 mm Hex end sockets	(Field Supplied)	-	-	-

Table 5. Safety

CRUSH HAZARD.
UNEXPECTED GANTRY ROTATION CAN CAUSE SERIOUS INJURY.
Never service the gantry with the axial drive enabled. Use the gantry rotation lock to lock out gantry rotation. See safety menu of Service Document gui for appropriate procedures.

Table 6. Required conditions
Condition	Reference	Effectivity
Only trained service personnel should service the GE CT Scanner.	-	-
Static strap and monitor must be used when working inside the detector.	-	-

Overview

This procedure defines the necessary steps to Remove and Install the Backplane.

Move table to home position, fully out and down.
Remove right side gantry cover.

Refer to Parts Replacement → Gantry → Enclosure → (Cover Removal Procedure).
Stop the rotor of X-ray tube in case of Liquid Bearing Tube before HVDC off. Refer to Liquid Bearing Tube Rotor stop procedure for details.
Turn OFF the Axial Drive and HVDC switches on the gantry’s Service Switch Panel.
Position the detector at 12 o'clock and lock gantry rotation.
Turn OFF the 120 VAC switch on the gantry’s Service Switch Panel.
Remove the gantry left side cover, top covers and front cover.

Cover the Tube Collimator port to protect it against dropped tools or screws. (Cloth or any other available item)
Remove the Air Plenum as shown in Detector Air Plenum Removal/Installation.
Remove the CDCB as shown in CDCB Replacement.
Remove the power board as shown in Power Board Replacement.
Disconnect cable connectors (J30, J31, J32, J33 and J51) from the back side of the DAS assembly.

Figure 1. Cable Connectors of Backplane
Disconnect 27 module connectors from the backplane.

Figure 2. Module Connectors
Remove long studs of CDCB and power board from the backplane.

Figure 3. Long Studs of CDCB and Power Board
Remove screws holding the backplane to the base frame of DAS/Detector.

Figure 4. Screws of Backplane
Hold the backplane, and tilt it slightly forward, then remove it upward.

Figure 5. Backplane Removal

Attach the new backplane to the base frame of DAS/Detector.
Tighten the screws to fix the backplane to the base frame of DAS/Detector.
Install the long studs of CDCB and power board.
Connect the 27 module connectors.
Connect the cable connectors (J30, J31, J32, J33 and J51) to the back side of the DAS assembly.
Install the power board as shown in Power Board Replacement.
Install the CDCB as shown in CDCB Replacement.
Install the Air Plenum as shown in Detector Air Plenum Removal/Installation.
Remove the cloth or any other item from the tube collimator port.

Make sure the Axial Drive, HVDC and 120 VAC switches on the gantry’s Service Switch Panel are OFF.
Release the gantry rotational lock and install gantry covers, all except the right side cover.

Refer to Replacement → Gantry → Enclosure → (Cover Removal Procedures).
Turn on the 120 VAC, HVDC and Axial drive service switches.
Install gantry right side cover.

Perform a [Quality Assurance Test] from the [Functional Checks] menu of the service manual to ensure system operation.
Perform a [Save State] to save new calibration data.