User's Manual

SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
ARINC 781-200 SDU and SCM
23-15-30 4-1
DATE TBD
TEST AND FAULT ISOLATION
This section provides test procedures to determine the operational readiness of SDU units.
There are no operational test procedures defined fo
r the SCM. SCM health is determined by
accessing the SDU BITE information.
If the A781-200 equipment passes all tests in this se
ction but does not function according to the
installation requirements, the fault may be with equipment or wiring outside the A781-200 system.
This section includes:
• Operational and Diagno
stic Testing
• Troubleshooting and Fault Isolation
• Adjustment/Alignment Procedures
• Modification History
NOTE: Depending on the version of software installed, the MPU menus described may differ from
those shown as examples in this manual.
1. Operational and Diagnostic Testing
This section includes the following sections:
• General
• Test and Fault Isolation Equipment Requirements
• SDU Maintenance Port Utility (MPU)
• Operational and Diagnostic Test Procedures
A. General
The A781-200 system requires testing for one of the following reasons:
• To verify the operational readiness of the system after installation on an aircraft
• To verify that a fault exists and produce system
reports for troubleshooting purposes
• To verify the operational readiness of repaired LRUs after re-installation on an aircraft
This section includes test and fault isolation pr
ocedures for the A781-200 system. All test
and load procedures require the A781-200 SDU MPU, which is accessed by connecting
to the maintenance port of the SDU.
B. Test and Fault Isolation Equipment Requirements
Table 4-1 lists the equipment required to access t
he SDU Maintenance Port Utility (MPU)
and perform operational and diagnostic testing on the SDU.