Cmos Archive And Restore (Power Switch Override) - Compaq 133756-004 - Deskpro EN - 6550 Model 6400 Maintenance & Service Manual

5.1.5

CMOS Archive and Restore (Power Switch Override)

Each time the system starts, the system ROM saves a copy of NVRAM (including CMOS,
passwords, and other system variables) in the flash ROM. Should the system become
unstable, the last known good copy of NVRAM can be restored using a feature called
"power button override." To restore NVRAM, do the following:
1. With the unit powered down, press and release the power button.
2. Immediately after pressing the power button (during POST), press and hold the power
button until the unit powers down (about 4 seconds).
At the next startup, the ROM detects this "power button override" event and the backup
copy of NVRAM is restored.
Because of this feature, users cannot power off the computer immediately after powering
up. The video display must be active before the computer can be powered off.
CAUTION: Unplugging the power cord during POST can corrupt the splash screen. Flashing the
ROM is required to restore the splash screen, although the computer will continue to function.
Compaq Deskpro EN Series of Personal Computers 5-5