Power Lights; System Lights - Dell OptiPlex 755 User Manual

Check the graphics card power cable connection —
Check the monitor settings — See the monitor documentation for instructions on adjusting the contrast and brightness, demagnetizing (degaussing) the
monitor, and running the monitor self-test.
Power Lights
CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the Product Information Guide.
The power button light located on the front of the computer illuminates and blinks or remains solid to indicate different states:
If the power light is green and the computer is not responding, see
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If the power light is blinking green, the computer is in standby mode. Press a key on the keyboard, move the mouse, or press the power button to
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resume normal operation.
If the power light is off, the computer is either turned off or is not receiving power.
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Reseat the power cable into both the power connector on the back of the computer and the electrical outlet.
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If the computer is plugged into a power strip, ensure that the power strip is plugged into an electrical outlet and that the power strip is turned
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on.
Bypass power protection devices, power strips, and power extension cables to verify that the computer turns on properly.
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Ensure that the electrical outlet is working by testing it with another device, such as a lamp.
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Ensure that the main power cable and front panel cable are securely connected to the system board (see the "System Board Components"
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section for your computer).
If the power light is blinking amber, the computer is receiving electrical power, but an internal power problem might exist.
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Ensure that the voltage selection switch is set to match the AC power at your location, if applicable.
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Ensure that the processor power cable is securely connected to the system board (see the "System Board Components" section for your
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computer).
If the power light is steady amber, a device may be malfunctioning or incorrectly installed.
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Remove and then reinstall the memory modules (see Memory).
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Remove and then reinstall any cards (see the "Cards" section for your computer).
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Eliminate interference. Some possible causes of interference are:
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Power, keyboard, and mouse extension cables
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Too many devices on a power strip
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Multiple power strips connected to the same electrical outlet
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System Lights
Your power button light and hard drive light may indicate a computer problem.
Power Light
Solid green
Blinking green
Blinks green several times and
then turns off
Solid yellow
Blinking yellow
Solid green and a beep code
during POST
Solid green power light and no
beep code and no video during
POST
Ensure that the power cable for the graphics card(s) is correctly attached to the card.
Problem Description
Power is on, and the computer is operating
normally. On the desktop computer, a solid green
light indicates a network connection.
The computer is in a power-saving mode.
A configuration error exists.
The Dell Diagnostics is running a test, or a device
on the system board may be faulty or incorrectly
installed.
A power supply or system board failure has
occurred.
A problem was detected while the BIOS was
executing.
The monitor or the graphics card may be faulty or
incorrectly installed.
Diagnostic Lights.
Suggested Resolution
No corrective action is required.
Press the power button, move the mouse, or press a key on the
keyboard to wake the computer.
Check the diagnostic lights to see if the specific problem is identified
(see Diagnostic Lights).
If the Dell Diagnostics is running, allow the testing to complete.
If the computer does not boot, contact Dell for technical assistance
(see Contacting Dell).
See Power Problems.
See Beep Codes for instructions on diagnosing the beep code. Also,
check the diagnostic lights to see if the specific problem is identified
(see Diagnostic Lights).
Check the diagnostic lights to see if the specific problem is identified
(see Diagnostic Lights).