Toshiba Satellite P20-25 Series, Maintenance Manual

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2 Troubleshooting Procedures 2.6 Keyboard Troubleshooting
To determine if the computer’s keyboard is functioning properly, perform the following
procedures. Figure 2-5 outlines the process. Start with Procedure 1 and continue with the other
procedures as instructed.
Procedure 1: External keyboard check
Procedure 2: Diagnostic check
Procedure 3: Connector and replacement check
Procedure 1 External keyboard check
Connect a USB keyboard to one of the computer’s USB ports, then boot the computer. The
computer automatically detects the external keyboard.
If the external keyboard works correctly, the internal keyboard or its connections may be faulty.
Go to Procedure 2.
If the external keyboard appears to have the same problem as the internal keyboard, the system
board may be damaged. Replace it with a new one following the instructions in Chapter 4.
Procedure 2 Diagnostic check
Run the Diagnostic Program, which will automatically execute the Keyboard Test. Refer to
Chapter 3,
Tests and Diagnostics for more information on how to run the program.
If an error is located, go to Procedure 3. If an error does not occur, the keyboard is functioning
properly.
Procedure 3 Connector and replacement check
The keyboard and/or system board may be disconnected or damaged. Disassemble the computer
following the steps described in Chapter 4,
Replacement Procedures and perform the following
checks.
Check 1 Make sure the keyboard cable is firmly connected to the system board.
If the connection is loose, reconnect firmly and repeat Procedure 2. If there is still an
error, go to Check 2.
Check 2 The keyboard may be damaged. Replace it with a new one following the instructions
in Chapter 4.
If the problem still exists, perform Check 3.
Check 3 The system board may be damaged. Replace it with a new one following the
instructions in Chapter 4.
2-18 Satellite P20-25 Series Maintenance Manual