Comtech EF Data RCS10 - Manual (Page 209)

RCS10 Redundant Communication System Maintenance
TM058 - Rev. 2.3 Page 4-1
Section 4 - Basic Troubleshooting and Maintenance
4.0 Periodic Maintenance
The DMD10 Modem requires no periodic field maintenance procedures. Should a unit be suspected
of a defect in field operations after all interface signals are verified, the proper procedure is to replace
the unit with another known working modem. If this does not cure the problem, faulty wiring, cabling
or power should be suspected.
4.1 Fuse Replacement
The RCS10 Baseband Board contains a lithium-type battery. This battery may explode if
mistreated. DO NOT attempt to recharge, disassemble or dispose of in fire. Replace only with the
same type recommended by the manufacturer. Dispose of lithium batteries properly.
4.1.1 Redundant Power Supply Fuse Replacement
Double-pole/neutral fusing is used. The AC power cord that is next to each fuse must be
disconnected before the fuse may be removed. To keep the RCS10 operational, be sure to
disconnect only one power cord at a time. Also, be sure to replace the fuse and the power cord
before checking the other fuse.
The AC fuses are located under the fuse cover next to each AC power plug. To remove a fuse, the
power cord must first be unplugged so that the cover can be slid away from the fuse and over the
AC receptacle. The fuse may now be removed for testing. Test the fuse with an ohmmeter or similar
device. If necessary, replace the fuse with a new 6.3 A, 250 V fuse. Be sure to replace the fuse with
one of the same type and rating. Failure to do so may result in damage to the equipment and may
result in a fire hazard.
4.2 Troubleshooting
The following is a brief list of possible problems that could be caused by failures of the modem or
improper setup and configuration for the type of service. The list is arranged by possible symptoms
exhibited by the modem.
Symptom: The Modem will not acquire the incoming carrier:
Possible Cause: Improper receive input to modem.
Action: Check that the receive cabling is correct.
Possible Cause: Receive carrier level too low.
Action: Check that the receive cabling is correct, that the downconverter is properly set
and that the LNA is turned on. If a spectrum analyzer is available, locate and measure the
receive level, which should not be below –55 dBm absolute.
Possible Cause: Receive carrier frequency outside of acquisition range.