Nortel Meridian SL-1 Supplementary Manual page 48

3-4 Upgrading from SL-1 S to Option 21
Shelf upgrades to Meridian 1 553-3001-253
6 If the system is presently equipped with a QPC742 FDI circuit pack,
disconnect the cable from the connector on the front of the pack,
remove the pack from the shelf.
• Remove QMM45 Disk drive and old adapter assembly.
• Insert the disk drive adapter assembly (Figure 3-1) in the position
vacated by the old adapter unit and secure to cabinet frame with
the four mounting screws.
• Insert the NT8D68AA Floppy Disk Unit in the disk drive adapter.
7 Invoke emergency transfer by operating the line transfer switch on the
QPC84 power monitor circuit pack to ON or 1.
8 Set the CAB INP circuit breaker at the front of the cabinet to OFF.
• Disconnect the ac power for the cabinet by disconnecting the
commercial ac power line cord from its receptacle or by setting
the commercial ac power supply circuit breaker at the service
panel to OFF.
• Disconnect all previously tagged cables from the connectors on
the QPC139 and QPC376 circuit packs.
9 Disconnect and remove any remaining cables connected to circuit
packs on the CE shelf.
Note: The main CE shelf is located at the bottom left shelf position in
the cabinet (viewed from the front). An optional expansion CE shelf
may be located at the top right shelf position.
10 Tag and disconnect the wires and the connector from the power
distribution harness to the backplane of the main CE shelf.
Note: If the cabinet is equipped with an expansion CE shelf (a
second CE shelf) disconnect and remove the wiring between the +5V,
+12V, -12V and LGND connections on the two CE shelves.
11 Remove the remaining circuit packs from the main CE shelf.