C.2 maintenance testing, C.2.1 test point samples, C.2.2 troubleshooting – Comtech EF Data DT-4500-A Series User Manual
Page 158: C.2.3 downconverter faults, C.2.3.1 prime power, C.2.3.2 dc power supply module
DT-4500-A Series Downconverters
Revision 1
Appendix C
MN-DT4500A
C–2
C.2 Maintenance Testing
The DT-4500-A Series Downconverters translate the input RF frequency to an output IF
frequency. The RF input level is -45 dBm (typical), and the RF output level is 0 dBm (typical).
To prepare for checkout, review the rack mounting information provided in Chapter 2.
INSTALLATION. Operations via the front panel (i.e., use of the menu system, keypad, and VFD)
are explained in detail in Chapter 5. FRONT PANEL OPERATION.
C.2.1 Test Point Samples
The IF output and RF input can be monitored at the RF Sample Test Points on the front panel. A
BNC connector is provided for the IF sample and an SMA connector is provided for the RF
output. The RF sample output level is -20 dBc nominal, and the IF sample level is -20 dBc
nominal.
C.2.2 Troubleshooting
Downconverter operating problems can be identified by first observing the LED status indicators
on the front panel. When a fault condition is indicated, or and marginal performance tolerance
condition exists, the specific fault or faults can be identified via the FAULTS menu branch,
accessible via front panel operation. See Sect. 5.3.3 FAULTS in Chapter 5. FRONT PANEL
OPERATION for more information about viewing current or stored faults.
Converter operational status screens are available via the MONITOR menu branch. See Sect.
5.3.2 MONITOR in Chapter 5. FRONT PANEL OPERATION for more information.
C.2.3 Downconverter Faults
C.2.3.1 Prime Power
Check the dual fuses on the rear panel. The required prime power is 100 to 125 VAC, or 205 to
240 VAC @ 1 Amp. The optional DC prime power is -48 VDC.
C.2.3.2 DC Power Supply Module
15 VDC: A fault ("FT") indicates a voltage level exceeding ± 10% of the power supply voltage.
Check the output of the DC Power Supply Module. The typical current output level is 3.0 amps.
Check all connections to make sure they are secure. If the voltage exceeds ± 10%, or the power
supply module current is not approximately 3.0 amps, or the fault still exists, remove the power
supply and return it to Comtech EF Data for repair.
14 VDC: A fault ("FT") indicates a voltage level exceeding ± 10% of the power supply voltage. The
14 VDC is developed in the modules. Check the output of the 15 VDC Power Supply Module,