Resetting Cmos - HP Compaq Pro 4300 Maintenance & Serice Manual

Resetting CMOS

The computer's configuration memory (CMOS) stores information about the computer's configuration.
CAUTION:
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
for information.
To reset CMOS, complete the following steps:
1. Shut down the operating system properly, then turn off the computer and any external devices,
and disconnect the power cord from the power outlet.
2. With the power cord disconnected, press the power button again to drain the system of any
residual power.
WARNING!
sure to disconnect the power cord from the wall outlet, and allow the internal system
components to cool before touching.
CAUTION:
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 Regulatory, Safety and Environmental Notices guide
for more information.
3. Remove the access panel.
4. Locate the header and jumper labeled CMOS.
NOTE:
the password jumper and other system board components, see the Illustrated Parts & Service
Map (IPSM). The IPSM can be downloaded from http://www.hp.com/support.
5. Remove the jumper and place it on pins 1 and 2.
6. Wait for three seconds, and then replace the jumper to its original position (pins 2 and 3).
7. Replace the access panel.
8. Reconnect the external equipment.
9. Plug in the computer and turn on power. Allow the operating system to start.
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.
Removing and replacing the CMOS jumper will reset CMOS values to factory defaults. It
To reduce the risk of personal injury from electrical shock and/or hot surfaces, be
When the computer is plugged in, the power supply always has voltage applied to
The password jumper is blue so that it can be easily identified. For assistance locating
Computer Setup (F10) Utility on page 10
Resetting CMOS 149