Service Manual

GSM-204-523
Replacing the power distribution box
31st Oct 01
Maintenance Information: Horizon macro outdoor
68P02902W04-A
CONTROLLED INTRODUCTION
Maint. 4–3
Replacing the power distribution box
Introduction to
power
distribution box
replacement
The circuit breakers in the power distribution box switch off if an
overtemperature alarm signal is received, and switch on again when the
temperature reset level is reached. The power distribution box will need to be
replaced if one or both of the circuit breakers fail to operate correctly.
Removing the
power
distribution box
To remove the power distribution box from the auxiliary equipment housing:
WARNING
The batteries are capable of supplying high short circuit
currents and as such provides a high energy hazard.
Isolate the auxiliary equipment housing from the main
cabinet by switching off the EXT BATT circuit breaker on
the dc circuit breaker panel in the main cabinet before
commencing work.
1. Check that the AEH has been isolated from the main cabinet.
2. Open the cabinet door, release the lid latch and raise the lid.
3. Switch off the circuit breakers on the front of the power distribution box
and then disconnect the dc input cables from the rear pair of Anderson
connectors on the left side of the power distribution box. If used,
disconnect the extension cables to another cabinet from the front pair of
Anderson connectors.
4. Unplug the alarm signal cables from PL1, PL2 and PL3 on the front of the
power distribution box.
5. Disconnect the two cables which connect the top bank of batteries (bank
2, row 2) to the power distribution box and tie the cables safely out of the
way. Undo the battery terminal connections between bank 2, row 2 and
bank 2, row 1 and then remove the row 2 battery tray, followed by the row
1 battery tray.
6. Disconnect the two cables which connect battery bank 1, row 2 to the
power distribution box and tie the cables safely out of the way.
7. Undo the eight M4 nuts which secure the power distribution box to the lid
and then remove the box.
8. Unplug the door microswitch alarm cable from the external alarm interface
board.
9. Unplug the power cables for the heater mats and the fan from the external
alarm interface board.
The procedure for removing the power distribution box is now complete.