2 Troubleshooting Procedures
2.4 System Board Troubleshooting
Libretto 50CT/70CT Maintenance Manual
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To use the printer port LED follow these steps:
1.
Be sure the computer is in Hibernation mode.
2.
Plug the printer port LED into the computer’s parallel port.
3.
Turn the computer on.
4.
Read the LED status from left to right as you face the back of the computer.
5.
Convert the status from binary to hexadecimal notation.
6.
If the final LED status is FFh (normal status), go to Procedure 4.
7.
If the final LED status matches any of the test status values in Table 2-4, go to
Procedure 5.
Table 2-4 Printer port LED Hibernation mode error status
Error status
Meaning of status
F1H
System BIOS RAM checksum error
F2H
Optional ROM or Optional Card (CGA,MDA) is connected
F7H
Extended memory checksum error
E1H
Instant on error (extended memory checksum error)
Procedure 4
Diagnostic Test Program Execution and Replacement Checks
Execute the following tests from the Diagnostic Test Menu. Refer to Chapter 3, Tests and
Diagnostics, for more information on how to perform these tests.
System test (1)
Memory test (2)
Printer test (6)
ASYNC test (7)
Real Timer test (9)
NDP test (10)
Expansion test (11)
Sound test (12)
If an error is detected during these tests, replace the System Board with a new one. If the
problem still exists, go to Procedure 5.
Summary of Contents for Libretto 50CT
Page 8: ...viii Libretto 50CT 70CT Maintenance Manual ...
Page 10: ...Chapter 1 Hardware Overview ...
Page 11: ...1 ii Libretto 50CT 70CT Maintenance Manual ...
Page 30: ...Chapter 2 Troubleshooting Procedures ...
Page 31: ...2 ii Libretto 50CT 70CT Maintenance Manual ...
Page 61: ...Chapter 3 Tests and Diagnostics ...
Page 62: ...3 ii Libretto 50CT 70CT Maintenance Manual ...
Page 64: ...3 iv Libretto 50CT 70CT Maintenance Manual 3 22 2 Operations 3 45 ...
Page 128: ...Chapter 4 Replacement Procedures ...
Page 129: ...4 ii Libretto 50CT 70CT Maintenance Manual ...
Page 167: ...Appendices ...
Page 168: ...App ii Libretto 50CT 70CT Maintenance Manual ...
Page 178: ...Appendix B Board Layout B 4 Libretto 50CT 70CT Maintenance Manual ...
Page 183: ...Appendix C Pin Assignments Libretto 50CT 70CT Maintenance Manual C 5 ...
Page 186: ...Appendix Appendix C Pin Assignments C 8 Libretto 50CT 70CT Maintenance Manual 43 GND 44 NC ...
Page 194: ...Appendix F BIOS Rewrite Procedures F 2 Libretto 50CT 70CT Maintenance Manual ...
Page 196: ...Appendix G Reliability G 2 Libretto 50CT 70CT Maintenance Manual ...