Object ID: 00000018WIA30E7F030GYZ
Topic ID: id_12374928 Version: 1.17
Date: Jan 17, 2020 10:20:24 AM

Magnet Microphone Replacement

Prerequisites

Table 1. Personnel requirements
Required persons	Preliminary requirements	Procedure	Finalization
2	Not Applicable	60 to 120 minutes	Not Applicable

Table 2. Tools and test equipment
Item	Quantity	Effectivity	Part number	Manufacturer
Non-Ferrous Service Tool Kit	1	-	5112581	-

Table 3. Replacement parts
Item	Quantity	Effectivity	Part number	Manufacturer
A-Port Legacy Cable Track Assembly	1	-	See FRU Manual	-
Rear Microphone Assembly	1	-	See FRU Manual	-
Front Microphone Assembly	1	-	See FRU Manual	-

About this task

Overview

This document describes the removal and installation of the rear and front microphones. The rear microphone is located inside the LPCA and the front microphone is attached to the front end bell. Both microphones connect to the SRI.

Replacing Rear Microphone

About this task

Before replacing a microphone, plug the replacement into the SRI (J31) to verify that the replacement microphone fixes the problem.

Procedure

Drive the LPCA and cradle into the bore to within 12 in (30 cm) of the end of the bridge.
At the foot of the table, twist or squeeze the cradle release handle to detach the cradle from the LPCA, and then pull the cradle by hand to the home position so that it is fully retracted onto the table top.
Perform LOTO on the PDU. See the MR Service Safety Manual, PN 5452735.
Remove the LPCA cover (four screws).

Figure 1. Removing LPCA Cover
Pull the microphone and housing out of the LPCA.

Figure 2. Removing Microphone and Housing from LPCA
Remove the microphone from its housing by gently pulling the microphone to the rear.

Figure 3. Removing Microphone from Housing
To remove and install the rear microphone, see LPCA Cable Tracks Replacement to replace the cable track.

Note:
Individual cables cannot be ordered or replaced. Order the entire cable track.
Remove the left side middle cover (see Side and Top Cover Removal and Installation).
The rear microphone attaches to the SRI (located on the side of the magnet) at J31.

Figure 4. SRI Cable/Connections
Install the microphone into the housing.
Install the microphone and housing into the LPCA.
Note:
Be sure to tuck in the receive cables fully, so as to not nick the exposed insulation on the cable track wires.

Install the LPCA cover and four screws.
Replace the left side middle cover.

Removal and Installation of Front Microphone

About this task

Before replacing a microphone, plug the replacement into the SRI (J32) to verify that the replacement microphone fixes the problem.

Procedure

Perform LOTO on the PDU. See the MR Service Safety Manual, PN 5452735.
Remove the split bridge. See Bridge and Longitudinal Drive Belt Replacement.
Remove the front end bell, handling the microphone cabling carefully while pulling it out. See Dock Removal and Reinstallation.
Disconnect the other end of the microphone cable at J32 located on the SRI.

Figure 5. SRI Cable Connections
Run the new microphone cable along the same path as the old one, connecting the plug end at J32 on the SRI.
Remove the four screws from the old microphone assembly on the end bell and detach the housing and cable from the cover. The cover of the old microphone assembly should remain attached to the end bell as it is epoxied in place. Remove the old o-ring from this cover. Discard the old assembly and cable.

Figure 6. Microphone Placement on Front End Bell
Carefully disassemble the new microphone assembly in the same way as above by removing the four screws. Set aside the new cover. Place the new o-ring into the old cover that is attached to the end bell. Attach the new microphone assembly to the old cover with the screws.
Reattach the front end bell and the split bridge.

Finalization

Remove LOTO from the PDU. See the MR Service Safety Manual, PN 5452735.
Verify that the microphone is functioning properly.