IBM IntelliStation E Pro, Hardware Maintenance Manual

Page: 41 / 182

Clearing CMOS
If you experience severe problems with the computer, and the computer does not
startup, the CMOS code might be damaged. You might need to clear CMOS to
recover. To clear CMOS, complete the following steps:
1. Turn off the computer and all attached devices.
2. Unplug all power cords from electrical outlets and remove the computer cover
(see “Removing the cover of the 6216” on page 45 or “Removing the cover of
the 6226” on page 60).
3. Locate the CMOS clear jumper (JP3) on the system board, removing any
adapters that impede access to the jumper.
CMOS
clear
jumper
(JP3)
4. Move the jumper to pins 2 and 3, wait for approximately 10 seconds; then,
return the CMOS clear jumper to pins 1 and 2.
5. Replace any adapters that were removed.
6. Replace the cover (see “Replacing the cover of the 6216” on page 55 or
“Replacing the cover of the 6226” on page 72), and reconnect all cables that
were disconnected.
7. Turn on the computer to restart the operating system.
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.
Diagnostics
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