Toshiba 710CDT Maintenance Manual page 53

2.10 Internal Modem Troubleshooting
This section describes how to determine if the computer's internal modem is functioning
properly. Perform the steps below starting with Procedure 1, continuing with the other proce-
dures as required.
Procedure 1:
Procedure 2:
Procedure 1 Diagnostic Test Program Execution Check
The internal modem Diagnostic Test program is stored on the computer's Diagnostic Disk.
This program checks the internal modem. Insert the Diagnostics disk into the computer's
floppy disk drive, turn on the computer and run the test. Refer to Chapter 3, Tests and Diag-
nostics, for details.
Check 1 Execute Modem Test 1. If an error occurs, the modem I/F board may be malfunc-
tioning. Replace the I/F board. If errors still occur, go to Check 2.
Check 2 Execute Modem Test 3. If an error occurs, the DAA module may be malfunctioning.
Replace the DAA module. If errors still occur, go to Check 3.
Check 3 Execute Modem Test 2. If an error occurs, the I/F board and DAA module may be
malfunctioning. Replace both.
If any other errors occur while executing the internal modem diagnostics tests, go to
Procedure 2.
Procedure 2 Connector Check and Replacement Check
The DAA board is connected to the modem I/F board. If the modem malfunctions, there may
be a bad connection between the DAA board and the modem I/F board, or between the modem
I/F board and the system board. The DAA module, modem I/F board or system board might
also be damaged.
Disassemble the computer following the steps described in Chapter 4, Replacement Proce-
dures and perform the following checks:
Check 1 Make sure DAA board PJ1 is connected firmly to the modem I/F board PJ1 and
that the modem I/F board PJ2 is connected firmly to the system board PJ605.
DAA board PJ1
710CDT/720CDT
Diagnostic Test Program Execution Check
Connector Check and Replacement Check
PJ1 Modem I/F board PJ2 PJ605 System board
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