Dell OptiPlex 390 (Mid 2011) - Manual (Page 8)

Memory
Minimum memory 1 GB
Maximum memory 8 GB
Drives Mini-Tower Desktop Small Form Factor
Externally accessible:
5.25 inch drive bays two one one (slimline)
Internally accessible:
3.5 inch drive bays two one one
Control Lights And Diagnostic Lights
Front of computer:
Power button light Blue light — Solid blue light indicates power-on state;
blinking blue light indicates sleep state of the
computer.
Amber light — Solid amber light when the computer
does not start, indicates a problem with the system
board or power supply. Blinking amber light indicates a
problem with the system board.
Drive activity light Blue light — Blinking blue light indicates that the
computer is reading data from or writing data to the
hard drive.
Diagnostic lights Four lights located on the front panel of the computer.
For more information on the diagnostic lights, see the
Service Manual at support.dell.com/manuals.
Back of computer:
Power supply light Green light — The power supply is turned on and is
functional. The power cable must be connected to the
power connector (at the back of the computer) and the
electrical outlet.
NOTE: You can test the health of the power system by pressing the power-supply
diagnostic button. When the system power supply voltage is within specification,
the power-supply diagnostic light comes on. If the LED does not light up, the power
supply may be defective. AC power must be connected during this test.
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