![Nortel QPC705 Maintenance Manual Download Page 23](http://html.mh-extra.com/html/nortel/qpc705/qpc705_maintenance-manual_1707058023.webp)
Equipment replacement
Page 19 of 34
QCA144 1.5 MB/S RPE Cabinet
Maintenance and equipment replacement
Procedure 8
QUAA3 Power Unit replacement
1
Set the AC BRKR breaker on the front of the –48 V rectifier to OFF.
2
Set the DC BRKR breaker on the QBL24 battery units (if equipped)
serving the cabinet to OFF.
3
If cabinet is equipped with EMI shields remove the bottom shield.
Remove the two screws at the top corners of the shield and lower
shield to disengage from cabinet.
4
Tag and disconnect connectors J1, J2, J3, J4, J5, J6, and J7 at rear of
QUAA3 unit.
5
Tag and disconnect wires from terminals 1, 2, 3, 4, 5, and 6 of TB4 at
rear of QUAA3 unit.
6
Perform this step only if a QPC705 converter is installed beside the
QUAA3 unit. From the front of the cabinet, remove screws securing the
QPC705 converter to the cabinet. Slide the QPC705 out of the cabinet
and set aside.
7
From the front of the cabinet, remove the two bolts securing the right
bottom of the QUAA3 unit to the cabinet.
8
Remove the two screws securing the left side of the QUAA3 unit to the
cabinet and remove unit from cabinet.
9
Position the replacement QUAA3 unit in the cabinet and secure to
cabinet with mounting screws and bolts.
CAUTION
Service in the cabinet is interrupted when replacing the QUAA3
power unit.