Comtech EF Data SDM-9000 - Manual (Page 178)

Maintenance SDM-9000 Satellite Modem
6–20 Rev. 4
MODULE Modulator module fault.
Typically indicates that the modulator module is missing or will
not program. Ensure the modulator card is present and is
properly seated. If the modulator card is properly seated, this
could indicate a problem in the M&C card, or in the interface
between the modulator and the M&C card. Another possible
cause is the modulator firmware may be installed incorrectly or
has a pin not making contact. Ensure the modulator firmware is
correctly seated. Return the defective card for repair.
PROGRAMMING Modulator programming fault.
Indicates the modulator module has failed to program a current
configuration parameter. If this fault occurs, contact EFData
Customer Support for assistance.
CONFIGURATION Modulator configuration fault.
Indicates the modulator module does not support a programmed
configuration parameter. This fault typically occurs when the
programmed configuration does not match the module hardware.
Ensure the programming of the modulator hardware matches the
configuration parameters.
6.2.2.2.2 Demodulator Faults
Fault/Alarm Possible Problem and Action
CARRIER DETECT Carrier detect fault. Indicates the decoder is not locked.
This is the most common fault displayed in the modem. Any
problem from the input data on the modulator end of the circuit to
the output of the decoder can cause this alarm.
First, ensure the demodulator has an RF input at the proper
frequency and power level. Ensure the demodulator data rate is
properly programmed. Verify the frequency of the data
transmitted from the modulator is within 100 PPM. Check the test
points on the demodulator and decoder for the eye pattern, data,
and clock to verify proper levels, activity, and phase
(Section 6.1.3).
IF SYNTHESIZER Demodulator IF synthesizer fault.
Indicates the demodulator IF synthesizer is faulted. This fault is a
hardware failure. Return the demodulator card for repair.
RX CLOCK SYN Receive data clock synthesizer fault.
Indicates a loss of lock on the reference of the demodulator clock
recovery oscillator. This is a hardware failure fault. Return the
demodulator card for repair.
I CHANNEL Loss of activity in the I channel of the quadrature demodulator.
Typically indicates a problem in the modulator side of the circuit.
Check for proper RF input to the demodulator. If the input to the
demodulator is correct, then the problem is in the baseband
processing. Return the demodulator card for repair.
Q CHANNEL Loss of activity in the Q channel of the quadrature demodulator.
Follow the same procedure as for the I channel fault.
DESCRAMBLER Descrambler alarm.
Indicates loss of activity in the descrambler.