Display And Vga Board Troubleshooting - Toshiba 430CDT Maintenance Manual

2.8

Display and VGA Board Troubleshooting

This section describes how to determine if the 430 series display is functioning properly.
Start with Procedure 1 and continue with the other procedures as instructed.
Procedure 1:
Procedure 2:
Procedure 3:
Procedure 4:
Procedure 5:
Procedure 1 Contrast Control Check (430CDS only)
Contrast is adjusted by the contrast dial. If the contrast does not change when you turn the
contrast dial, perform Procedure 2.
Procedure 2 External CRT Check
Connect the external CRT to the 430 series external monitor port, then boot the computer.
The computer automatically detects the external CRT even if Resume mode is enabled.
If the external CRT works correctly, the internal LCD display may be damaged. Go to
Procedure 4.
If the external CRT appears to have the same problem as the internal LCD, the display
controller may be damaged. Go to Procedure 3.
Procedure 3 Diagnostic Test Program Execution Check
The Display Test program is stored on the 430 series Diagnostics Disk. This program checks
the display controller on the VGA board. After loading Toshiba MS-DOS, run the Diagnos-
tic Program. Refer to Chapter 3, Tests and Diagnostics, for details.
If an error is detected, go to Procedure 4. If an error is not detected, the display is functioning
properly.
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Contrast Control Check (430CDS only)
External CRT Check
Diagnostic Test Program Execution Check
Connector Check
Replacement Check
430 Series