Comtech EF Data SMS-458B - Manual (Page 87)

5–1
Chapter 5. MAINTENANCE
This chapter describes switch faults and their probable causes.
5.1 Fault Descriptions
5.1.1 General
The FAULT menu, [NEXT], and [PREV] keys allow the operator determine the cause of
any switch faults indicated by a red LED on the switch front panel. The following
sections describe faults and their probable causes.
5.1.2 Modulator Operation Fault
A MOD fault occurs when a modulator backup operation fails. The cause of the failure
can be one of the following:
• More failed modulators than available backups.
• No compatible backup available.
• All backups are in use.