Toshiba PORTEGE R400 Maintenance Manual page 55

2.4 System Board Troubleshooting
This section describes how to determine if the system board and CPU are defective or not
functioning properly. Start with Procedure 1 and continue with the other procedures as
instructed.
The procedures described in this section are:
Procedure 1: Message Check
Procedure 2: Debugging Port Check (Boot Mode)
Procedure 3: Diagnostic Test Program Execution Check
Procedure 4: Replacement Check
PORTEGE R400 Maintenance Manual (960-623)
2 Troubleshooting Procedures
[CONFIDENTIAL] 2-17