Toshiba Portege M780, Maintenance Manual

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Troubleshooting Procedures
2.7 Keyboard Troubleshooting
To check if the computer’s keyboard is malfunctioning or not, follow the troubleshooting
procedures below as instructed.
Procedure 1: Diagnostic Test Program Execution Check
Procedure 2: Connector Check and Replacement Check
2.7.1 Procedure 1 Diagnostic Test Program Execution Check
Execute the Keyboard Test (DIAGNOSTIC TEST) and Pressed key display test (ONLY ONE
TEST) in the Diagnostic Program. Refer to Chapter 3,
Tests and Diagnostics
, for more
information on how to perform the test program.
If an error occurs, go to Procedure 2. If an error does not occur, keyboard is functioning
properly.
2.7.2 Procedure 2 Connector Check and Replacement Check
The connection of cable and board may be defective. Otherwise, they may be faulty.
Disassemble the computer following the steps described in Chapter 4,
Replacement
Procedures
, and perform the following checks:
Check 1 Make sure keyboard cable is firmly connected to system board.
If the connection is loose, reconnect firmly and repeat Procedure 1. If the problem
still occurs, go to Check 2.
Check 2 Keyboard may be faulty. Replace it with a new one following the instructions in
Chapter 4,
Replacement Procedures
. If the problem still occurs, perform Check 3.
Check 3 System board may be faulty. Replace it with a new one following the instructions
in Chapter 4,
Replacement Procedures
.
2-40 [CONFIDENTIAL] PORTEGE M780 Maintenance Manual (960-809)