Comtech EF Data SDM-9000 - Manual (Page 159)

Rev. 4 6–1
6
Chapter 6.
MAINTENANCE
This chapter provides system checkout and troubleshooting information.
6.1 System Checkout
This section provides instructions for checking the modem setup within the earth station.
Due to the complexity of the modem circuitry, this checkout procedure should be used as
a basic guideline only. Maintenance tests that are more complicated are beyond the scope
of this manual.
The system checkout consists of test instructions for the interface, modulator, and
demodulator PCBs. The instructions include tables and test points for ensuring that the
E
b
/N
0
, typical output spectrums, typical eye patterns, and constellation pictures are
correct. If a test failure occurs, refer to Section 6.2 for the fault isolation procedures.
CAUTION
This equipment contains parts and assemblies sensitive to damage by ESD.
Use ESD precautionary procedures when touching, removing, or inserting
PCBs.
6.1.1 Interface
Use the following procedure and the test setup in Figure 6-1 to inspect the interface PCB.
Refer to Chapter 5 for the interface specifications. Section 6.1.4.1 lists the interface test
points and signal names. Figure 6-5 shows the test point locations.