Using Light Path Diagnostics To Troubleshoot The System Board - IBM BladeCenter HS20 Installation And User Manual

Using light path diagnostics to troubleshoot the system board

You have to remove the blade server from the BladeCenter unit, open the cover,
and press the light path diagnostics switch (SW4) to light any error LEDs that were
turned on during processing. These LEDs can be used to help troubleshoot system
board component problems. See the illustrations in this section, and Table 2 on
page 18 and Table 3 on page 19 for information about locating light path
diagnostics LEDs and what to do if there is an error LED lit. Table 7 on page 61
provides more information about the light path diagnostics LED locations, settings,
and error solutions. Refer to these illustrations and tables when solving problems
with the blade server.
Power is available to relight the light path diagnostics LEDs for a small period of
time after the blade server is removed from the BladeCenter unit. During that period
of time, you can relight the light path diagnostics LEDs for a maximum of 25
seconds (or less, depending on the number of LEDs that are lit and the length of
time the blade server is removed from the BladeCenter unit) by pressing the light
path diagnostics button. The light path diagnostics power present LED (CR111) is lit
when the light path diagnostics button is pressed if power is available to relight the
blade-error LEDs. If the light path diagnostics power present LED (CR111) is not lit
when the light path diagnostics button is pressed, no power is available to light the
blade-error LEDs, and they will be unable to provide any diagnostic information.
Table 1. Switch block 2 (SW2) settings
Switch number
SW2
Description
Switch block 2 has eight switches:
v 1 - BIOS backup page
– Off: the BIOS starts from the Primary BIOS page.
– On: the BIOS starts from the backup BIOS page.
v 2 - Wake On LAN bypass
– Off: Enabled
– On: Disabled (default)
v 3 - Reserved
v 4 - Power on override
– Off: Normal operation (default)
– On: Enabled
v 5 - Reserved
v 6 - Clear CMOS
– Off: Disabled
– On: Enabled
v 7 - Reserved
v 8 - Bypass power-on password during next server
start
– Off: Disabled (default)
– On: Enabled
Chapter 2. Power, controls, jumpers, switches, and indicators
17