Service manual

GS80 Component Removal and Replacement 6-35
If a power subrack needs replacing, it is unlikely that an operating system is
running in the drawer powered by it. In some cases it is possible to keep part of
the system running, but we recommend that the entire system be brought down.
Removal
1. Shut down the operating system and put the OCP switch in the Off position.
2. Open the front and rear doors of the cabinet.
3. At the back, trip the main circuit breaker on the AC input box(es).
4.
Unplug power and signal cables connected to the subrack distribution panel.
5.
Remove the two Phillips head screws holding the subrack to its supporting plate.
6. Move to the front of the cabinet and remove the power supplies from the subrack and
set aside. See Section 6.14.
7. Remove the plastic fillers at the bottom of the power cabinet to gain access to the back
of the AC input boxes. To remove the fillers, pinch the snaps at both ends of the guard
and lift it away from the frame.
8. Unplug the power cords from the AC input box that go to the target subrack.
9. Remove any tie wraps dressing the power cords that would prevent them from being
removed with the subrack. Gather the cords so that when the subrack is pulled out of
the front of the cabinet the cords do not catch on anything.
10. Remove the four Phillips head screws holding the subrack to the frame and slide the
rack out of the cabinet. Take care that the power cords attached to the back of the
subrack are free to travel with it.
Replacement
Reverse the steps outlined in the removal procedure.
Be sure the power cords are placed back in the same locations from which they were
removed.
Verification
Power on the drawer(s). 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.