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2-25
Check 2:
The keyboard controller on the system board may be damaged. Replace the System
PCB, which contains the system board, with a new one. Refer to Chapter 4, Replace-
ment Procedures for more information about how to replace the System PCB.
2.8
Display Troubleshooting
This section describes how to determine if the T4500/T4600 Family’s display is functioning
properly. Start with Procedure 1 and continue with the other procedures as instructed.
Procedure 1: Brightness and Contrast Control Check
Procedure 2: External CRT Check
Procedure 3: Diagnostic Test Program Execution Check
Procedure 4: Connector Check
Procedure 5: Replacement Check
Procedure 1
Brightness and Contrast Control Check
Brightness and contrast may be changed by using Hot keys. If the display is blank, go to Check 1.
If you cannot change the brightness and contrast, go to Check 3.
NOTE: The contrast control is effective only on the T4500 or T4600 monochrome LCD. You
cannot change the contrast on the T4500C or T4600C Color LCD.
If the contrast does not change when you execute the following checks, perform Procedure 2.
Check 1:
Pressing
Fn
+
F5
selects the active display device. Each time you press
Fn
+
F5
, the
active display device changes in the following order: LCD; Dual Display (which
activates both the LCD and CRT); and CRT.
If the display is still blank, go to Check 2.
Check 2:
Pressing
Fn + F1
sets the computer in the instant security mode. Once set in this
mode, the display becomes blank and the keyboard is locked to prevent others from
gaining access to your computer. To restore the computer from the instant security
mode, enter the instant password or turn the power off and back on.
Summary of Contents for T-Series T4500
Page 4: ...1 4 Figure 1 3 T4600 T4600C System Unit Configuration ...
Page 24: ...1 24 ...
Page 169: ...4 54 ...
Page 175: ...B 2 B G K N O R P Q C S I D H F T C A M E J Figure B 2 T4500 T4500C System PCB FSH4S1 Back L ...
Page 177: ...B 4 B 2 T4600 T4600C System Board Figure B 3 T4600 T4600C System PCB FSH1S1 Front ...
Page 178: ...B 5 Figure B 4 T4600 T4600C System PCB FSH1S1 Back ...
Page 196: ...D 1 APPENDIX D ASCII Character Codes Table D 1 ASCII Character Codes ...