Radio Assembly; Control Heads - Gm338 And Gm398; Radio Chassis And Transceiver Board; Control Head Fitting - Motorola GM338 Service Manual

Radio Assembly

7.0 Radio Assembly
7.1

Control Heads - GM338 and GM398

1. On the GM338 only, locate the display in the control head ensuring that the two cut-outs in the
display are aligned with their corresponding indentations, then press the display into place.
Insert the top and bottom elastomeric connector strips into the spaces above and below the
display respectively.
NOTE Care should be taken not to touch or contaminate the conductive pads on the under-
side of the display and the elastomeric connectors (GM338 only).
2. Fit the rubber keypad onto the board ensuring that the ON/OFF control and microphone on
the board locate correctly with the cut-outs in the keypad.
3. On the board, rotate the ON/OFF control spindle fully counter-clockwise.
4. Also, rotate the volume knob on the front housing fully counter-clockwise.
5. Align the board with the control head, inserting the ON/OFF control spindle and microphone
connector through the holes in the control head.
6. Ensure that the keypad, ON/OFF control spindle and microphone connector are aligned with
the control head then press the board into place until it clicks.
7. On the GM338, insert the speaker tube and speaker into the control head and press it in until
it clicks. Connect the speaker connector to the board.
7.2

Radio Chassis And Transceiver Board

1. Inspect the transceiver board chassis and if required reapply thermal grease to the heatsink
area on the chassis and heat dissipating devices. You may have to remove damaged thermal
pads from the chassis and devices prior to applying the grease.
2. Insert the transceiver board at an angle (approximately 30°) into the chassis taking care to
slide the antenna connector and accessory connector into their cut-outs in the chassis.
3. Lower the transceiver board onto the chassis and align the two locating holes in the board
with the locating pins in the chassis.
4. Secure the cover to the chassis with the six screws previously removed.
5. Torque the six screws to 1.9 NM (17 in lbs) using the T20 TORX™ driver. Begin with the two
screws located in the middle of the chassis followed by the four outer screws. Since the
screws usually take a set, torque the screws a second time (1.9 NM) in the same order.
6. Refit the top cover over the assembled radio chassis. Press the cover down until it snaps into
place.
7.3

Control Head Fitting

1. Align the "0" mark on the flex with the "0" mark on the chassis to the socket on the radio
assembly as shown in Figure 2-2.
2. Check that the back housing o-ring seal is undamaged and fitted in the groove. Replace the
seal if it is damaged (refer to the exploded view diagrams and parts list).
3. Fit the back housing to the control head. Ensure that the tags on the back housing align with
the snap catch grooves on the control head. Press the back housing into place until it snaps
into place.
4. Check that the radio chassis o-ring seal is undamaged and fitted in the groove on the chassis
assembly. Replace the seal if it is damaged.
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