System-board switches, jumpers, and buttons

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

Note

If there is a clear protective sticker on the top of the switch blocks, you must remove and discard it to access the switches.

Figure 1. System-board switches, jumpers, and buttons

The following table describes the jumpers on the system board.

Table 1. System board jumpers
Jumper number	Jumper name	Jumper setting
JP1	CMOS clear jumper	Pins 1 and 2: Normal (default). Pins 2 and 3: Clears the real-time clock (RTC) registry.
JP2	UEFI boot backup jumper	Pins 1 and 2: Normal (default). Loads the primary server firmware ROM page. Pins 2 and 3: Loads the secondary (backup) server firmware ROM page.
JP20	System TPM physical presence jumper	Pins 1 and 2: Normal (default). Pins 2 and 3: Indicates a physical presence to the system TPM.
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 (JP2) 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 SW3 switch block on the system board.

Table 2. System board SW3 switch block definition
Switch number	Default position	Description
1	Off	Reserved.
2	Off	Reserved.
3	Off	Reserved.
4	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.

Important

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, Handling static-sensitive devices, and Turning off the server.
Any system-board switch or jumper block that is not shown in the illustrations in this document are reserved.

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

Table 3. Button on the server
Button name	Function
Force 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).

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