M-BIST (Built-In Self-Test)
L-BIST (LCD Built-In Self-Test)
system does not start-up properly (no
POST).
Trigger
Pressing
M
key and power button
Pressing
D
key and power button. Also automatically
initiated during POST. Automatically initiated during POST
Indicator of fault
Amber colored battery indicator LED
Battery indicator LED blink error code [Amber, White] =
[2,8]
Repair instruction
Indicates a problem with the system
board.
Indicates a problem with the system board.
M-BIST
About this task
The M-BIST (Built-In Self-Test) diagnostics tool allows users to diagnose system-board failures.
NOTE:
M-BIST can be manually-initiated before POST (Power-On Self-Test).
How to run M-BIST?
M-BIST must be initiated from a power-off state with the computer either connected to the supplied AC power adapter or running on a
fully-charged battery.
Steps
1
From the power-off state, press and hold both the
M
key on the keyboard and the power button to initiate M-BIST.
2
With both the
M
key and the power button held down, the battery indicator LEDs exhibit two states:
a
OFF:
No fault is detected with the system board.
b
AMBER:
Indicates a problem with the system board.
LCD Built-In Self-Test (BIST)
About this task
LCD BIST is a diagnostic tool that helps you determine if a screen abnormality is an inherent problem with the LCD screen of the computer,
with the video card or with the computer's settings.
It is recommended to run BIST to isolate the cause of a screen abnormality if you encounter display issues such as:
•
flickering
•
distortion
•
clarity issues
•
fuzzy or blurry image
•
horizontal or vertical lines
•
color fading
Starting the LCD BIST test
Steps
1
Power off your computer.
2
Disconnect any peripherals connected to your computer. Connect only the supplied AC power adapter to your computer.
3
Ensure that the LCD screen is clean with no dust particles on the surface of the screen.
4
From the power-off state, press and hold the
D
key and power button to enter LCD BIST mode. Continue to hold the
D
key, until you
see color bars on the LCD screen.
78
Troubleshooting
