System-board switches and jumpers

The following illustration shows the location and description of the switches, jumpers, and buttons.

Important

1. Before you change any switch settings or move any jumpers, turn off the server; then, disconnect all power cords and external cables. Review the information in Safety, Installation guidelines, and Turning off the server.
2. Any system-board switch or jumper block that is not shown in the illustrations in this document are reserved.
3. If there is a clear protective sticker on the switch blocks, you must remove and discard it to access the switches.

Figure 1. Location of the switches, jumpers, and buttons on the system board

The following table describes the jumpers on the system board.

Table 1. Jumpers definition.

The jumper description table with one level of row and column headers.

Jumper name	Description
Clear CMOS jumper	Pins 1 and 2: Keep CMOS data (default) Pins 2 and 3: Clear CMOS data
Low security jumper (JP12)	Pins 1 and 2: Low security asserted Pins 2 and 3: Low security not asserted (default)
UEFI boot backup jumper (JP16)	Pins 1 and 2: Normal (default). Loads the primary server firmware ROM page. Pins 2 and 3: Boot from backup. Loads the secondary (backup) server firmware ROM page.
Note If no jumper is present, the server responds as if the pins are set to the default. Changing the position of the UEFI boot backup jumper from pins 1 and 2 to pins 2 and 3 before the server is turned on alters which flash ROM page is loaded. Do not change the jumper pin position after the server is turned on. This can cause an unpredictable problem.

The following table describes the functions of the SW1 switch block on the system board.

Table 2. System board SW1 switch block definition.

The switch description table with one level of row and column headers.

Switch number	Default position	Description
1	Off	Asserts TPM physical presence. When this switch is toggled on, the TPM physical presence is asserted.
2	Off	Power-on password override. Changing the position of this switch bypasses the power-on password check the next time the server is turned on and starts the Setup utility so that you can change or delete the power-on password. You do not have to move the switch back to the default position after the power-on password in overridden. Changing the position of this switch does not affect the administrator password check if an administrator password is set. See Passwords for additional information about passwords.
3	Off	Default off.
4	Off	Asserts IMM2 reset. When this switch is toggled on, the IMM2 reset is asserted.

The following table describes the functions of the button on the system board.

Table 3. Button definition.

The button description table with one level of row and column headers.

Button name	Definition
NMI button	This button is on the rear of the server. Press this button to force a nonmaskable interrupt to the microprocessor. You might have to use a pen or the end of a straightened paper clip to press the button. You can also use it to force a blue-screen memory dump (use this button only when you are directed to do so by Lenovo Support).