HP ProLiant BL420c User Manual page 38

If another SAS controller is installed, do the following:
5.
Flush the original cache to remove all data. For more information, see the Configuring Arrays on HP
a.
Smart Array Controllers Reference Guide on the HP website
(http://www.hp.com/support/SAC_UG_ProLiantServers_en).
CAUTION: Always be sure that both captive screws are disengaged before removing the SAS
controller. Failure to disengage the screws may result in damage to the SAS controller.
Disengage the SAS controller captive screws and use the handle to remove the SAS controller.
b.
Locate and remove the cache module
c.
original SAS controller, if installed. This cache module is located near the rear of the system board
and is not required when installing an HP Smart Array P220i Controller.
IMPORTANT:
("System board
Always close the SAS controller handle before installing the SAS controller.
components" on page 8) associated with the
Hardware options installation 38