Service manual

3-6 AlphaServer 4000/4100 Service Manual
3.2 Troubleshooting Power Problems
Power problems can occur before the system is up or while the system is
running. If a system stops running, make a habit of checking the PCM.
Power Problem List
The system will halt for the following:
1. A CPU fan failure
2. A system fan failure
3. An overtemperature condition
4. Power supplied out of tolerance
5. Circuit breaker(s) tripped
6. AC problem
7. Interlock switch activation or failure
8. PCM failure
9. Environmental electrical failure or
unrecoverable system fault
with auto_action ev = halt or boot
10.Operator error - failure to unplug all power
supplies and letting Vaux drain (10 sec delay)
before restarting
11.Cable failure
12. Module failure - System motherboard, PCI
motherboard, or system bus to PCI bus bridge
13. SCM breaking the interlock circuit
Indications of failure:
1. Power control module LEDs indicate
CPU fan, system fan, overtemperature,
and power supply failures
2. Circuit breaker(s) tripped
No obvious indications for failures 7 - 13
from the power system.
PKW0436A-96
If Halt Is Caused by Power, Fan, or Overtemperature
If a system is stopped because of a power, fan, or overtemperature problem, use the
PCM LEDs to diagnose the problem. See Section 3.2.1.