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"Compaq.com - Compaq Presario Series Maintenance and Service Guide - Models: 1683, 1685, 1687, 1688, and 1690
Display has overheated. If computer is in direct sunlight,
move it and allow it to cool off.
Display is blank and the Suspend icon
is flashing.
System is in Suspend mode. Press any key or touch the Touch
Pad.
Internal display is blank and the
screen on an external monitor
displays information.
Display function was switched to
the external monitor.
Use Fn + F2 to switch between LCD
or CRT.
Problem Probable Cause Solution(s)
Internal display flashes or has garbled
characters when computer is connected to
external monitor.
Using 1024 x 768 or higher
resolution on external
monitor and have toggled
back to internal display,
which supports up to
800 x 600.
Restart the computer.
The light tubes on the edge of the display
panel do not light up at all and Power-On
Self-Test (POST) completes when the unit is
powered up.**
Improper backlight or
display cable connections
Replace the display assembly.
Defective inverter board. Replace the display assembly.
Defective display cable. Replace the display assembly.
Defective display panel. Replace the display assembly.
Defective system board. Replace the system board.
The light tubes on the edge of the display
panel do not light up at all and Power-On
Self-Test (POST) does not complete when
the unit is powered up.**
Defective system board. Replace the system board.
Backlight (brightness) cannot be adjusted
with Fn + F7 (¯ ) or
Fn + F8 (- ).***
Improper display cable
connections.
1. Reseat the display cable to the
system board.
2. Replace the display assembly.
Defective inverter board. Replace the display assembly.
Defective display cable. Replace the display assembly.
Defective system board. Replace the system board.
Contrast cannot be adjusted with
Fn + F5 (¯ ) or Fn + F6 (- ).
Improper display cable
connections.
1. Reseat the display cable to the
system board.
2. Replace the display assembly.
Defective inverter board. Replace the display assembly.
Defective display cable. Replace the display assembly.
Defective system board. Replace the system board.
** This problem indicates that the backlight or its power circuitry has failed. Since you cannot observe the POST
result on the display panel when the backlight is not functioning, connect the unit to an external monitor before
powering the unit up. If an external monitor is not available, verify that POST completes by opening and closing
the display, listening for the single or double beep, and watching for the LEDs turn on at the front of the
computer.
file:///C|/SERVICE%20MANUALS/COMPAQ%20_%20chec...01685%201687%201688%201690%201694/solving.html (5 of 8)6/27/2004 2:57:51 AM