5-4 Troubleshooting Procedures
Table 5-1 contains fault isolation information for Display Problems on the notebook.
Symptoms are listed along the left side of the chart and the various Display FRUs are
listed along the top of the chart. Within the body of the table are the probabilities of
each of the FRUs causing that particular problem. For example, a single display line
on the screen is most likely caused by the LCD Panel or Display Cable; other components
have a low probability of causing the problem.
5.3.3 Fault Isolation Using Power On Self Test
When the computer is first powered up, it automatically performs a Power On Self Test
(POST) that checks the notebook’s central hardware and memory functions. During
POST (which lasts for a few seconds), the display shows copyright and version number
information.
Note: Some procedures in this paragraph require you to use keystroke
sequences, such as Ctrl-Alt-Del. To execute a keystroke sequence such as this,
you must press all three keys simultaneously.
Table 5-1 Display Troubleshooting Guide
Problem Description Inverter
Board
LCD
Panel
Display
Cable
Mother
Board
BIOS
Single line on LCD display (horizontal
or vertical) Low High Medium Low Low
Multiple lines on display (horizontal or
vertical) Low Medium Medium Low Low
Sections of the display are missing
characters Low Medium Medium Low Low
Scrambled Display Low Medium Low Medium Medium
Intermittent characters on display Low Medium Medium Medium Low
Bright display, no visible characters Low Medium Medium Medium Low
Brightness level fluctuating or display
blinking on/off High Low Medium Low Low
Display goes dim over time High Medium Low Low Low
Dim display but characters very
visible Medium Medium Low Low Low
Very dark display and characters are
slightly visible when a light is directed
at surface of the display
High Low Low Low Low
Very dark display and no characters
are visible Low High High Medium Low