IBM eX5 Implementation Guide

Chapter 8. IBM BladeCenter HX5 375

8.1.2 Clearing CMOS memory

When a server is shipped from one location to another location, you have no idea what the

server was exposed to. For all you know, it might have been parked next to a large magnet or

electric motor and everything in the server that stores information magnetically has been

altered, including the CMOS memory. IBM does not indicate on the shipping carton that

magnetic material is enclosed, because the information is readily recoverable.

Booting the server to the F1 system configuration panel and selecting Load Default Settings

restores the default values for the items that you can change in the configuration. This option

does not change the settings of registers that are used by the Integrated Management

Module (IMM) and the UEFI. These registers define the system state of the server. When they

become corrupt, the server can display the following symptoms:

򐂰 Fail to power on.

򐂰 Fail to complete POST.

򐂰 Turn on amber light path diagnostic lights that describe conditions that do not really exist.

򐂰 Reboot unexpectedly.

򐂰 Fail to detect all of the installed CPU, memory, PCIe adapters, or physical disks.

You cannot restore or modify these internal registers to their defaults by using the F1 system

configuration panel; however, you can restore these internal registers to their defaults by

clearing the CMOS memory.

There are two key ways to clear the CMOS. One method is by jumper and the second method

is by removing the CMOS battery. We describe each method in the following sections.

Jumper method

Use the following procedure to clear the CMOS using the jumper method:

1. Power-cycle the real-time clock (RTC). Locate the switch block SW2 in the middle of the

system board at the extreme rear of the server, as shown in Figure 8-3. You must remove

all of the expansion cards to reach the jumper block.

Figure 8-3 Switch block SW2 location

SW2

0987654321

ON

RTC switch

(SW2-5)