IBM 81Y Computer Hardware User Manual


 
32 Hardware Maintenance Manual: xSeries 250
Power checkout
Power problems can be difficult to troubleshoot. For instance, a short circuit can exist
anywhere on any of the power distribution busses. Usually a short circuit will cause
the power subsystem to shut down because of an overcurrent condition.
A general procedure for troubleshooting power problems is as follows:
1. Power off the system and disconnect the AC cord(s).
2. Check for loose cables in the power subsystem. Also check for short circuits, for
instance if there is a loose screw causing a short circuit on a circuit board.
3. Remove adapters and disconnect the cables and power connectors to all internal
and external devices until system is at minimum configuration required for
power on (see "Minimum operating requirements" on page 154).
4. Reconnect the AC cord and power on the system. If the system powers up
successfully, replace adapters and devices one at a time until the problem is
isolated. If system does not power up from minimal configuration, replace FRUs
of minimal configuration one at a time until the problem is isolated.
To use this method it is important to know the minimum configuration required for a
system to power up (see page 154). For specific problems, see “Power error
messages” on page 167.
Temperature checkout
Proper cooling of the system is important for proper operation and system reliability.
For a typical server, you should make sure:
Each of the drive bays has either a drive or a filler panel installed
Each of the power supply bays has either a power supply or a filler panel installed
The top cover is in place during normal operation
There is at least 50 mm (2 inches) of ventilated space at the sides of the server and
100 mm (4 inches) at the rear of the server
TEMP The system temperature has exceeded the maximum
rating.
1. Check to see if a fan has failed. If it has, replace the fan.
2. Make sure the room temperature is not too high. (See “Features
and specifications” on page 3.)
If the problem persists, see “Temperature checkout”.
NON
RED
Server drawing too much power to operate in a
redundant power mode.
System can continue to operate in a nonredundant power mode. To
operate in a redundant mode, add a power supply or remove most
recently installed options.
OVER
SPEC
The server is drawing more power than the power
supplies are rated for.
Either add a power supply or remove a device from the server.
PS1 The first power supply has failed. Replace the first power supply.
PS2 The second power supply has failed. Replace the second power supply.
PS3 The third power supply has failed. Replace the third power supply.
PS4 The fourth power supply has failed. Replace the fourth power supply.
LED Cause Action
Table 1. Light path diagnostics.