Gantry New Balance Sensor Hardware Replacement

Prerequisites

Table 2. Tools and test equipment
Item	Quantity	Effectivity	Part number	Manufacturer
3 mm and 5 mm Hex wrenches	1	-	-	-
Gantry balance weight kit (delivered with system)	1	-	-	-
ESD static strap	1	-	-	-
Deep-well socket ½" drive	1	-	Part of Balance Kit shipped with system	-
Field Torque wrench kit	1	-	46-268445G1 or 5135228 or equivalent	-
½” drive torque wrench from Tool Depot	1	-	46-268521G1 or 5133203 or equivalent	-

Table 5. Safety

Follow ALL required safety and PPE procedures customary for your organization, when working on this product.

Overview

This procedure defines the steps necessary to replace the gantry balance sensor hardware.

Drive the table to its full back position and position it full up if not already there.
Remove gantry right side cover.

Refer to Parts Replacement > Gantry > Enclosure > (Cover Removal Procedure).
Turn off 120 VAC, Axial Drive and HVDC Service Switches.
Remove the Gantry left side, the front cover can stay connected to the gantry cables, just needs to be moved away from the gantry toward the table..
Set up Field ESD strap connecting it to a gantry ground point. Wear the strap when replacing any of the gantry balance circuit boards in the following sections.

Remove the cable connector from the balance sensor board.
Remove the balance sensor cover with the circuit board from the Gantry Frame by unscrewing four (4) screws

Figure 1. Balance Sensor Assy
Remove the defective circuit board from the cover by unscrewing two (2) screws, then install the new one to the cover.

Figure 2. Balance Sensor Board Replacement
Reinstall the balance sensor cover with the circuit board to the Gantry Frame.
Reconnect the cable connector to the balance sensor board.
Turn on the gantry 120VAC service switch and press the table drives enable at the lower right corner of the service switch panel.
Return the gantry to a zero tilt position using switch S10. Then turn Tilt Enable S9 to Off and put the Service Mode switch in the down position.
Turn the 120VAC service switch off.
Reinstall the tilting assembly side safety panel. (5 mm hex wrench)

At the console, go to the Service Desktop and select Shell from the Utilities tab.
Type the following command line to remove the current sensitivity matrix and exit the shell.

rm /usr/g/fw/sensmatrix.dat
exit

Perform Gantry Service balance from the Common Service Desktop Calibrations Tab. This procedure will have you install the gantry balance trial weights to create a new sensitivity matrix. Reference the Gantry Balance Procedure if needed.
Reinstall gantry left side cover.

Refer to Parts Replacement > Gantry > Enclosure > (Cover Removal Procedure).
Turn on the gantry 120 VAC, HVDC and Axial drive service switches.
Install the gantry right side cover.
Run the System scanning test from the Functional Checks procedure list.