MiTAC 7521 PLUS/N service manual Maintenance Diagnostics

7521Plus / N N/B MAINTENANCE

7.Maintenance Diagnostics

7.1Introduction

Each time the computer is turned on, the system bios runs a seririeses ofof internalinternal checks on the hardware. This power-on self test (post) allows the computeromputer toto detect problems as early as the power-on stage. Error messages of postpost cancan alertalert you to the problems of your computer.

If an error is detected during these tests, you will see an error messagemessage displayed on the screen. If the error occurs before the display is initialized,thenitialized,then thethe screen cannot display the error message. Error codes or system beepseps areare usedused toto identify a post error that occurs when the screen is not available.

The value for the diagnostic port (378H) is written at the beginningning ofof thethe testtest.. Therefore, if the test failed, the user can determine where the problemlem occurredoccurred byby reading the last value written to port 378H by the 378H port debugg boardboard plugplug atat

PIO PORT.

98