Service manual

GS80 Component Removal and Replacement 6-21
only hard partitions can be powered off. Pull the 48V power supplies from the subrack
powering the drawer with the FRU. (This removes both 48V and Vaux from the
drawer.) Skip to step 4.
3. Trip the circuit breaker on the AC input box powering the drawer(s).
4. Access the drawer with the faulty backplane. See Section 6.1.1 or 6.1.2.
5. Remove all modules from the drawer. See Sections 6.2 through 6.6.
6. Disconnect the CSB ribbon cable.
7. To disconnect the global port cables from the backplane, slip a small flathead
screwdriver through the small hole(s) in the left side of the drawer and insert the
blade between the plastic cable guide and the lip of the connector.
Twist the
screwdriver so that one edge of the cable rises out of the connector. Repeat this
procedure on the other edge of each cable, pull the cable from the connector and move
it out of the way.
8. Remove the drawer faceplate by removing the six Phillips head screws that hold it in
place.
9. Disconnect the ground strap from the backplane and tuck it under the backplane tray.
10. At the front of the backplane disconnect the signal cable next to the main power
module connector and tuck it down under the backplane tray.
11. Disconnect the power harness connected to the backplane connector.
12. Unscrew the Phillips head screw holding the backplane tray to the drawer and slide
the tray and backplane forward out of the drawer.
Replacement
Reverse the removal procedure.
Route cables so that they do not interfere with modules when they are replaced.
Verification
Power up the system. If you tripped the AC circuit breaker, be sure to put the circuit
breaker in the on position before you put the OCP keyswitch in the On position.