IBM 220, Hardware Maintenance Manual

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Hardware Maintenance Manual: xSeries 220
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 125).
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 125).
Recovering BIOS
If the BIOS has become damaged, such as from a power failure during a flash update,
you can recover the BIOS using the flash ROM page-swap jumper (J38) and a BIOS
flash diskette.
Note: You can obtain a BIOS flash diskette from one of the following sources:
• Use the ServerGuide program to make a BIOS flash diskette.
• Download a BIOS flash diskette from the World Wide Web. Go to
http://www.ibm.com/pc/support/, select IBM Server Support, and
make the selections for your server.
The flash memory of your server consists of a primary page and a backup page. The
J38 jumper controls which page is used to start the server. If the BIOS in the primary
page is damaged, you can use the backup page to start the server; then, start the BIOS
flash diskette to restore the BIOS to the primary page.
To recover the BIOS, do the following:
1. Turn off the server and peripheral devices and disconnect all external cables and
power cords; then, remove the cover.
2. Locate jumper J38 on the system board.