User's Manual

SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
ARINC 781-200 SDU and SCM
23-15-30 4-7
DATE TBD
(b) BITE
If equipment connected to the A781-200 system provides wrong information or
do
es not provide a signal to the A781-200 SDU, the SDU cannot function
properly. You can check the status of connected equipment with the MCDU BITE
screens. To check the status of connected equipment, follow the procedure
described in "Viewing BITE Information" on page 2-15 and "Troubleshooting and
Fault Isolation" on page 4-7.
The SATCOM BITE menu provides information about the results from BITE for
var
ious parts of the A781-200 system.
• If BITE fails the SDU or SCM, remove the component from service and return
it to
RCI—see "Maintenance and Repair" on page 5-1.
• If BITE fails a component other than the A781-200 SDU or SCM, verify the
operation of that c
omponent and test the satellite communication system
again.
2. Troubleshooting and Fault Isolation
This section provides troubleshooting procedures for A781-200 systems.
Troubleshooting procedures require data obtained using the MCD
U. For specific instructions
on how to access and use the MCDU, refer to "Operating the MCDU" on page 2-2.
NOTE: All of the MCDU menus discussed in this section are accessed from the SATCOM
BITE menu.
A. Subsystem Health
The SATCOM SUBSY HLTH menu provides the BITE st
atus of subsystem components.
To check the subsystem health, on the SATCOM BITE menu, press the button next to
SUBSY HL
TH.
Figure 4-2 illustrates the SATCOM SUBSY HLTH menu.
Table 4-8 Power-On Test Procedure
Step Action
1.0 Follow the test setup procedure in Table 4-6 on page 4-6.
2.0 Power-on the SDU.
3.0 Check the status of the front panel LEDs. V
erify that the green LED flashes for 60
seconds and then turns off. Verify that the red LED is not illuminated. For more
information about the LED signals, refer to "LEDs" on page 1-9.
4.0 Review the BITE status of all system components using the MCDU. Verify that all
subsy
stems show OK status. For more information about using the MCDU and
viewing BITE, refer to "Operating the MCDU" on page 2-2 and "BITE" on page 4-7.
5.0 Follow the post test procedure in Table 4-7 on page 4-6.