JHL90 Service Manual
This section describes how to determine if the compu
properly. The process is outlined in Figure 6-3. Start
ter’s display is functioning
with Procedure 1 and
continue with the other procedures as instructed.
• Procedure 1: External display check
• Procedure 2: Diagnostic check
• Procedur
4.1 Procedure 1 External display check
Connect an external display to the computer’s external monitor port, then boot the
computer The computer automatically detects the external display. Press Fn+F5
to switch to the external display.
If the external display works correctly, the internal LCD may be damaged. Go to
Procedure 3.
If the external monitor appears to have the same problem as the internal monitor,
the system board may be damaged. Go to Procedure 2.
4.2 Procedure 2 Diagnostic check
The Display Test program is stored on the computer’s Diagnostics disk. This
program checks the display controller on the system board. Insert the Diagnostics
disk in the computer’s floppy disk drive, turn on the computer and run the test.
Refer to Chapter 3,
Tests and Diagnostics for details.
If an error is detected, go to Procedure 3. If an error is not detected, the display is
functioning properly.
4.3 Procedure 3 Connector and replacement check
The FL inverter board, LCD module, and system board are connected to the
display circuits. Any of these components may be damaged.
Replacement
Procedures
, for instructions on how to disassemble the computer and then
perform the following checks:
Check 1
Make sure the DDRRAM module is seated properly. Test display again.
• If the problem still exits, replace the DDRRAM module.
• If the problem still exists, perform check 2.
Check 2
Replace the FL inverter board with a new one and test display again.
• If the problem still exists, perform Check 3.
e 3: Connector and replacement check
6-11
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