Tait TB9300, Installation And Operation Manual, Page: 111 / 138

TB9300 Installation and Operation Manual
Replacing Modules 111
© Tait Limited March 2016
8.5 Replacing a Power Management Unit
Notice
You must disconnect the AC and DC power cables before
removing the PMU from the subrack.
Removal
1. If you have not already done so, carry out the instructions in “Pre-
liminary Disassembly” on page 105 .
2. At the front of the PMU, unplug and remove the output power
cable
b
to the subrack interconnect board. Also unplug and remove
the system control bus cable
c
.
3. Unplug the output power cable to the PA
d
and move it to one side.
4. Loosen the screws securing the retaining clamps
e
and rotate the
clamps through 90° to clear the module.
5. Slide the PMU out of the subrack, taking care not to damage any of
the cables.
Refitting
1. Slide the replacement PMU into the subrack and secure it with the
retaining clamps.
2. Reconnect all the front and rear panel cables previously
disconnected. Connect the DC power cables on the rear panel as
shown in
Figure 5.8 on page 90 . Tighten the screws to a torque of
18–20lbf·in (2–2.25N·m). 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 119 ).
3. Carry out the instructions in “Final Reassembly” on page 114 .
(obscured)
b
c
d
d
e e