Dell OptiPlex 990 (Early 2011) - Manual (Page 74)

Problem Description A possible system board resource and/or hardware failure has
occurred.
Troubleshooting
Steps
• Clear CMOS.
• Disconnect all internal and external peripherals, and
restart the computer. If the computer boots, add the
peripheral cards back one by one until you find the
bad one.
• If the problem persists, the system board / system
board component is faulty.
LED
Power Button
Problem
Description Some other failure has occurred.
Troubleshooting
Steps
• Ensure that the display/monitor is plugged into a
discrete graphic card.
• Ensure that all hard drives and optical drive cables are
properly connected to the system board.
• If there is an error message on the screen identifying a
problem with a device ( hard drive), check the device
to make sure it is functioning properly.
• If the operating system is attempting to boot from a
device (optical drive), check system setup to ensure
the boot sequence is correct for the devices installed
on your computer.
Beep Codes
The computer can emit a series of beeps during start-up if the display cannot
show errors or problems. These series of beeps, called beep codes, identify
various problems. The delay between each beep is 300 ms, the delay between
each set of beeps is 3 sec, and the beep sound lasts 300 ms. After each beep
and each set of beeps, the BIOS should detect if the user presses the power
button. If so, BIOS will jump out from looping and execute the normal shutdown
process and power system.
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