Chapter 4. Customer Replacement Units (CRUs)
Customer Replacement Units (CRUs) are computer parts that can be upgraded
or replaced by the customer. There are two types of CRUs: Tier 1 and Tier 2.
Tier 1 CRUs are easy to install, whereas Tier 2 CRUs require some technical
skill and tools.
The User Guide and Hardware Replacement Guide provide instructions for
replacing Tier 1 and Tier 2 CRUs. Refer to the following table to determine
which publication contains the instructions you need.

To view a publication, open the Start menu from the Windows desktop, select

All Programs, select Online Books, and click Online Books. Double-click on

the appropriate publication for your machine type. For more information about
accessing the User Guide and Hardware Replacement Guide, refer to “Online
Books folder” on page 25. The publications also are available on the Lenovo

We b site at http://www.lenovo.com.

Note: Only use computer parts provided by Lenovo. Refer to Chapter 3,
“Lenovo Statement of Limited Warranty,” on page 29 for warranty
information about the CRUs for your machine type.
6490, 8700, 8701, 8705, 8717, 8973, 8975, 8979, 8983, 8985, 8991, 8995, 9265, 9269, 9277,
9279, 9283, 9287, 9379, 9383, 9387, 9389, 9631, 9635, 9637, 9646, 9648, 9694
User Guide
Hardware Replacement
Guide
Tier 1 CRUs
Optical drive x x
Hard disk drive x x
Memory x x
Mouse x x
Keyboard x x
Adapter card x x
Tier 2 CRUs
Diskette drive x x
Heat sink x
Power supply x

System fan x

© Lenovo 2005, 2006. Portions © IBM Corp. 2005. 69