Service manual

3-2 AlphaServer 4000/4100 Service Manual
3.1 Troubleshooting with LEDs
During power-up, reset, initialization, or testing, diagnostics are run on CPUs,
memories, bridge modules, PCI motherboards, and sometimes options. The
following sections describe possible problems that can be identified by checking
LEDs.
Figure 3-1 CPU and Bridge Module LEDs
TEMP_OK
IOD1 Self-Test Pass
IOD0 Self-Test Pass
POWER_FAN_OK
Bridge Module LEDs (IOD 0 & 1)
IOD3 Self-Test Pass
IOD2 Self-Test Pass
Bridge Module LEDs (IOD 2 & 3)
PKW0400C-97
DC_OK
SROM Oscillator
CPU Self-Test Pass
CPU LEDs
Normally On
Normally Off
Regulator OK (EV56)