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User's Guide
POST Codes
When the machine is turned on, the hexadecimal display should show the various POST codes as
the system executes (unless it has a rare BIOS that does not display POST codes).
If the machine does not boot, system POST has detected a fatal fault and stopped. The number
showing in the hexadecimal display on the Diagnostic Card is the number of the test in which
POST failed. Refer to Appendix A for a listing of POST codes.
Troubleshooting During POST
After initial power up, Power-On Self-Test (POST) codes begin displaying on the Diagnostic
Card's hexadecimal displays (for most machines).
NOTE: A few machines use the parallel port to display POST codes instead of the Diagnostic
Card.
THE POST PROCESS
The ROM built onto the motherboard of the computer rums its built-in POST (Power-On Self-Test)
when you switch power on to the computer, press the reset button on the computer, or press Ctrl-Alt-Del (warm
boot). POST performs a tightly interwoven initialization and testing process
for each of these methods, but it typically does not test or initialize memory above 64K for warm
boot. You can get an even better idea of the detailed process by studying the POST code listings in
Appendix A.
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