Dell OptiPlex 990 Service Manual page 90

Controls and Lights
Network activity light on integrated
network adapter
Power supply diagnostic light
Power Wattage
Mini-Tower 265 W
Desktop 250 W
Small Form 240 W
Factor
90
Maximum Voltage
Heat
Dissipation
1390 BTU/hr 100 VAC to 240 VAC, 50 Hz to 60 Hz, 5.0 A
1312 BTU/hr 100 VAC to 240 VAC, 50 Hz to 60 Hz, 4.4 A
1259 BTU/hr 100 VAC to 240 VAC, 50 Hz to 60 Hz, 3.6 A;
100 VAC to 240 VAC, 50 Hz to 60 Hz, 4.0 A
Orange — a good 100 Mbps
connection exists between the
network and the computer.
Yellow — a good 1000 Mbps
connection exists between the
network and the computer.
Off (no light) — the computer is not
detecting a physical connection to
the network.
Yellow light — A blinking yellow
light indicates that network activity
is present.
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 test button. When
the system power supply
voltage is within specification,
the self-test LED lights up. If the
LED does not light up, the
power supply may be defective.
AC power must be connected
during this test.