5. Continue with one of the following actions:
vIf you did remove the DS5020 CRUs before installation (as described in
“Removing the CRUs” on page 36), continue with “Replacing the
components.”
vIf you did not remove the DS5020 CRUs before installation, continue with
Chapter 3, “Cabling the storage subsystem,” on page 45.
Replacing the components
If you removed components from the DS5020 storage subsystem before you
installed it into a rack cabinet, use the following procedures to replace the
components in the DS5020 after it is installed successfully in a rack cabinet.

Replacing a controller

Complete the following steps to replace the controller that you removed before the
installation.
Attention: After you remove an controller, wait 70 seconds before reseating or
replacing the controller. Failure to do so might cause undesired events. The left and
right controllers are seated in the DS5020 chassis in opposite orientations. If you
cannot fully insert the controller into the controller bay, flip it 180° and reinsert it.
1. Slide one controller into the empty slot in the storage subsystem. Be sure that
the lever is pulled straight out as you slide the controller in, as shown in
Figure 21.
2. As you slide the controller into the empty slot, make sure the guide pins on the
side of the controller fit into the notches. After the guide pins fit into the notches
and the controller fits snugly into the bay, push the lever downward or upward
90°, depending on whether the controller is inserted in the Aor B controller bay
to fully latch it into place. Do not force fit. The controller is designed to prevent it
from being inserted into the chassis incorrectly.
Attention: Make sure that the levers lock into place in the storage subsystem
chassis.
3. Repeat step 1 and step 2 to replace the second controller.
Lever
Guide pin
Notch
Figure21. Removing and replacing a controller
42 IBM System Storage DS5020 Storage Subsystem: Installation, User’s, and Maintenance Guide