Comtech EF Data DMDVR20 LBST Rev 1.1 - Manual (Page 76)

DMDVR20 LBST Satellite Modem Maintenance and Troubleshooting
TM136 – Rev. 1.1 6-1
Maintenance and Troubleshooting
6
This section discusses unit maintenance and troubleshooting for the Universal Satellite Modem.
The DMDVR20 LBST contains a Lithium Battery. DANGER OF
EXPLOSION exists if the battery is incorrectly replaced. Replace only
with the same or equivalent type recommended by the manufacturer.
Dispose of used batteries in accordance with local and national
regulations.
6.0 Periodic Maintenance
There is no external fuse on the modem. The fuse is located on the power supply assembly
inside the case, and replacement is not intended in the field.
6.0.1 Clock Adjustment
The modem allows for VCO speed adjustment from the front panel. Clock adjustment should be
performed only when an internal clock source has insufficient accuracy for the custom modem
application.
6.1 Troubleshooting
Should a unit be suspected of a defect in field operations after all interface signals are verified,
the correct procedure is to replace the unit with another known working unit. If this does not cure
the problem, wiring or power should be suspect.
The following is a brief list of possible problems that could be caused by failures of the modem or
by improper setup and configuration for the type of service. The list is arranged by possible
symptoms exhibited by the modem.