System-Board Switches - IBM 7870B4U Service Manual

System-board switches

Use this information to locate and define system-board switches in the blade
server.
The following illustration shows the location of the light path diagnostics switch
on the system board.
The following table describes the function of each switch in the switch blocks
(SW1, SW2, SW3).
16
BladeCenter HS22 Type 7870, 1936, and 1911: Problem Determination and Service Guide
Switch number Description
SW1 - 1 Password override
switch
SW1 - 2 Trusted Platform
Module (TPM)
physical presence
SW1 - 3 ICH9 RTC reset
SW1 - 4 Boot using the backup
IMM code.
SW1
SW3
Switch setting
Changing position of
this switch resets the
power on password.
The default position is
off.
Normally open. Toggle
to reset RTC.
The default position is
off, allowing the blade
server to boot from the
primary IMM
firmware.
Definition
This switch overrides
the power on
password. The system
ships with this switch
off, but it can be on or
off in a functioning
system.
Turning this switch to
the on position
indicates a physical
presence to the TPM.
Resets the RTC. A
momentary toggle is
all that is required. To
avoid excessive battery
drain, do not leave this
switch closed.
When the switch is in
the default off
position, the blade
server will boot using
the primary IMM
firmware. When the
switch is on, the blade
server will boot using
a backup of the IMM
firmware.