Hardware Reference Manual

Table A-1 Diagnostic Front Panel LEDs and Audible Codes (continued)
Activity Beeps Possible Cause Recommended Action
Power LED flashes 12 times,
once every second, followed
by a two second pause.
Beeps stop after third iteration
and the computer reboots.
12 Health timer expired. None.
System does not power on
and LEDs are not flashing.
None System unable to power
on.
Press and hold the power button for less than 4
seconds. If the hard drive LED turns green, the
power button is working correctly. Replace the
system board.
OR
Press and hold the power button for less than 4
seconds. If the hard drive LED does not turn on
green then:
1. Check that the unit is plugged into a
working AC outlet.
2. Ensure that the DC power cable is plugged
into the I/O panel.
3. Replace the power supply.
64 Appendix A Troubleshooting