Comtech EF Data CIM-300L - Manual (Page 147)

CiM-300L IP Enabled Satellite Modem Rev. 1
System Checkout/Fault Isolation CD/CIM300L.IOM
121
7.1.6.3 D
EMODULATOR
F
AULTS
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. Refer to the fault
isolation procedure for Data Clock Syn in the modulator section. Verify the
frequency of the data transmitted from the modulator is within 100 PPM.
IF SYNTHESIZER Demodulator IF synthesizer fault.
Indicates the demodulator IF synthesizer is faulted.
This fault is a hardware failure. Contact the Adaptive Broadband Customer
Support Department.
I CHANNEL Indicates a 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.
Q CHANNEL Indicates a loss of activity in the Q channel of the quadrature demodulator.
Follow the same procedure for the I channel fault.
BER THRESHOLD Indicates the preset BER threshold has been exceeded.
Setting of this alarm is done in the Utility menu. This is an alarm based on the
corrected BER reading on the front panel.
MODULE Demodulator module fault.
Typically indicates that the demodulator module is missing or will not program.
Contact the Adaptive Broadband Customer Support Department.
CONFIGURATION Modulator/Demodulator Configuration fault.
Indicates a fault in either the Modulator or Demodulator state.
LNB CURRENT LNB Current fault.
Indicates a fault in LNB Current..