Dell OptiPlex 990 Desktop Service Manual page 99

System Board Connectors
Processor
Processor Fan
Service mode jumper
Password clear jumper
RTC reset jumper
Internal speaker
Intruder connector
Power connector
Mini-Tower, Desktop,
Small Form Factor
Ultra Small Form Factor
Controls and Lights
Front of the computer:
Power button light
Drive activity light
Diagnostic lights
one 1155-pin connector
one 5-pin connector
one 2-pin connector
one 2-pin connector
one 2-pin connector
one 5-pin connector
one 3-pin connector
one 24-pin and one 4-pin connector
one 8-pin, one 6-pin, and one 4-pin
connector
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.
Blue light — Blinking blue light
indicates that the computer is
reading data from or writing data to
the hard drive.
Four lights located on the front
panel of the computer. For more
information on the diagnostic lights,
99