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Comtech EF Data OM20 User Manual

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OM20 Universal Outdoor Modem

Maintenance and Troubleshooting

MN-OM20– Revision 5

7–2

Symptom

Possible Cause

The Modem will not acquire the
incoming carrier:

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.

Modem is in Test Mode.

The Async Port is not
configured correctly.

The switches may not be set in the correct positions.

7.2.1 Alarm Faults

7.2.1.1

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.