![background image](http://html.mh-extra.com/html/ibm/thinkpad-500/thinkpad-500_hardware-maintenance-manual_607423009.webp)
1.4.1 Power-On Self Test (POST)
Each time you power-on the system, POST is initiated. The POST takes up
to 90 seconds to complete, depending on the options installed.
The POST checks the following:
System Board
Memory
Display
Keyboard
Diskette Drive
Hard Disk Drive
Parallel Port
Serial Port
To start the POST, power-on the system. The following will happen:
1. You will hear one short beep when the POST successfully ends.
If the POST cannot be completed successfully, an error message appears
on the display accompanied by the Configuration Utility box requesting
the user to press the Esc or Enter key. When the Esc key is pressed,
the system bypasses the error and attempts to complete the POST. If
the Enter key is pressed, the Configuration Utility is shown. The user
can then try to correct the error. If a critical error is
encountered, the POST is halted.
2. The system attempts to load the operating system as customized. If an
operating system is not found, a graphic message (icon) is displayed
requesting the user to insert a diskette into the diskette drive and
press the F1 (RESUME = "F1" KEY) key to resume operation.
IBM ThinkPad 500 HMM
Power-On Self Test (POST)
¦ Copyright IBM Corp. 1993
1.4.1 - 1