HP ProDesk 400 G2 Small Form Factor Maintenance And Service Manual page 125

1. Turn off the computer and any external devices, and disconnect the power cord from the power outlet.
2. Disconnect the keyboard, monitor, and any other external equipment connected to the computer.
WARNING! To reduce the risk of personal injury from electrical shock and/or hot surfaces, be sure to
disconnect the power cord from the wall outlet, and allow the internal system components to cool
before touching.
CAUTION: When the computer is plugged in, the power supply always has voltage applied to the
system board even when the unit is turned off. Failure to disconnect the power cord can result in
damage to the system.
Static electricity can damage the electronic components of the computer or optional equipment. Before
beginning these procedures, ensure that you are discharged of static electricity by briefly touching a
grounded metal object. See the Safety & Regulatory Information guide for more information.
3. Remove the computer cover or access panel.
CAUTION: Pushing the CMOS button will reset CMOS values to factory defaults. It is important to back
up the computer CMOS settings before resetting them in case they are needed later. Back up is easily
done through Computer Setup. See
up the CMOS settings.
4. Locate, press, and hold the CMOS button in for five seconds.
NOTE: Make sure you have disconnected the AC power cord from the wall outlet. The CMOS button will
not clear CMOS if the power cord is connected.
NOTE: For assistance locating the CMOS button and other system board components, see the
Illustrated Parts & Service Map (IPSM).
5. Replace the computer cover or access panel.
6. Reconnect the external devices.
7. Plug in the computer and turn on power.
NOTE: You will receive POST error messages after clearing CMOS and rebooting advising you that
configuration changes have occurred. Use Computer Setup to reset any special system setups along
with the date and time.
For instructions on Computer Setup, see
Computer Setup (F10) Utility on page 61
Computer Setup (F10) Utility on page
for information on backing
61.
Clearing and resetting the CMOS 117