IBM IntelliStation A Pro 6224, Hardware Maintenance Manual And Troubleshooting Manual

Page: 33 / 172

Power checkout
Power problems can be difficult to solve. For example, a short circuit can exist
anywhere on any of the power-distribution buses. 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. Turn off the computer, and disconnect all ac power cords.
2. Check for loose cables in the power subsystem. Also check for short circuits, for
example, 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 the computer is at the minimum configuration
required to start the computer (see page 104).
4. Reconnect all ac power cords and turn on the computer. If the computer starts
successfully, replace adapters and devices one at a time until the problem is
isolated. If the computer does not start from the minimal configuration, replace
FRUs of the minimal configuration one at a time until the problem is isolated.
To use this method, you must know the minimum configuration that is required for
the computer to start (see page 104).
Chapter 3. Diagnostics
23