User's Manual

Table Of Contents

TB9400 Installation and Operation Manual Replacing Modules 105

8.4 Replacing a Power Amplifier

Notice Before removing a PA, first disconnect the DC input, transmit

forward input and transmit reverse output, followed by the RF output.

After refitting the PA, reconnect the RF output first, followed by the

transmit forward input, transmit reverse output, and then the DC input.

Removal 1. If you have not already done so, carry out the instructions in “Pre-

liminary Disassembly” on page 101.

2. At the front of the PA, unplug the DC input

b, transmit forward c

and transmit reverse

d cables, and move the cables to one side.

Unplug both ends of the system control bus cable

e and remove it.

3. At the rear of the PA, unplug the RF output cable.

4. Loosen the screw securing the retaining clamp(s)

f and rotate the

clamp(s) through 90° to clear the module.

5. Slide the PA out of the subrack, taking care not to damage any of the

cables.

Refitting 1. Slide the replacement PA into the subrack and secure it with the

retaining clamp(s).

2. At the rear of the PA, connect the RF output cable.

3. At the front of the PA, connect the transmit forward and transmit

reverse cables, followed by the DC input cable.

4. Reconnect all the other front and rear panel cables previously

disconnected. Ensure the front panel cables are positioned correctly,

and retained where required by the cable retaining clips in the top of

the subrack (refer to “Appendix B – Inter-Module Connections” on

page 117).

be d cff

50W PA 100W PA