Dell EMC PowerEdge R640 Installation And Service Manual page 162

Steps
1 Turn off the system, including any attached peripherals, and disconnect the system from the electrical outlet.
2 Remove the system cover.
3 Move the jumper on the system board jumper from pins 2 and 4 to pins 4 and 6.
4 Install the system cover.
The existing passwords are not disabled (erased) until the system boots with the jumper on pins 4 and 6. However, before you assign a
new system and/or setup password, you must move the jumper back to pins 2 and 4.
NOTE: If you assign a new system and/or setup password with the jumper on pins 4 and 6, the system disables the new
password(s) the next time it boots.
5 Reconnect the system to its electrical outlet and turn on the system, including any attached peripherals.
6 Turn off the system, including any attached peripherals, and disconnect the system from the electrical outlet.
7 Remove the system cover.
8 Move the jumper on the system board jumper from pins 4 and 6 to pins 2 and 4.
9 Install the system cover.
10 Reconnect the system to its electrical outlet and turn on the system, including any attached peripherals.
11 Assign a new system and/or setup password.
162 Dell EMC PowerEdge R640 Installation and Service Manual
Jumpers and connectors