Operating instructions

Maintenance and Troubleshooting DMD20/DMD20 LBST Universal Satellite Modem
6-2 TM103 – Rev. 2.8
Symptom Possible Cause
There is an improper receive input to modem.
The Receive Carrier Level is too low.
The Receive Carrier Frequency is outside of the acquisition
range.
The Transmit Carrier is incompatible.
The Modem will not acquire the
incoming carrier:
Modem is in Test Mode.
The Async Port is not
configured correctly.
The switches may not be set in the correct positions.
6.1.1 Alarm Faults
6.1.1.1 Major Tx Alarms
Alarm Possible Cause
FPGA CFG Indicates a transmit FPGA hardware failure.
DSP CFG Indicates a transmit FPGA failure.
SCT Clock PLL Indicates that the Tx SCT Clock PLL is not locked. This
alarm will flash on during certain modem parameter
changes. A solid indication points toward a configuration
problem within the modem.
SYM Clock PLL
Indicates that the Tx Symbol Clock PLL is not locked. This
alarm will flash on during certain modem parameter
changes. A solid indication points toward a problem with the
incoming clock to the modem (SCTE).
LB Synth PLL Indicates that the Tx L-Band Synthesizer is not locked. This
alarm will flash on during certain modem parameter
changes. A solid indication points toward a configuration
problem within the modem.
IF Synth PLL Indicates that the Tx IF Synthesizer is not locked. This
alarm will flash on during certain modem parameter
changes. A solid indication points toward a configuration
problem within the modem.
Ethernet WAN Indicates that the WAN Port is down.