Comtech EF Data SDM-300A - Manual (Page 345)

SDM-300A Satellite Modem Revision 6
Troubleshooting MN/SDM300A.IOM
18–9
Table 18-2. SDM-300A Fault Tree
TX I
F OUTPUT OFF
TX FAULT LED TX FAULT RELAY RX FAULT LED RX FAULT RELAY COM EQ FAULT LED COM EQ FAULT RELAY TX ALARM LED TX ALARM RELAY #2 RX ALARM LED RX ALARM RELAY #3 SPARE RELAY AL
ARM #1
PRIMARY ALARM RELAY SECONDARY ALA
R
M RELAY
IBS BACKWARD ALARM DEFFERED MAIN ALARM TX AI
S
RX AIS D&I TERR BWA
MODULATOR FAULTS
(1) (2) (3) (4) (5)
(6)
**
*** (7)
**
***
**
***
(8)
*
*
**
*** *
**
***
***
IF SYNTHESIZER X X X X X X
DATA CLOCK SYN X X X X X X
I CHANNEL X X X X X X
Q CHANNEL X X X X X X
AGC X X X X X X
MODEM REF ACT X X
MODEM REF PLL X X X X X X
DEMODULATOR FAULTS
CARRIER DETECT X X X X X
IF SYNTHESIZER X X X X X
I CHANNEL X X X X X
Q CHANNEL X X X X X
BER THRESHOLD X X X X
MODULE X X X X X
Legend
Note Fault/Alarm Relay Test Points Connector/Pins
(1) TX FAULT Pin 4 (NO), 5 (COM), 6 (NC) ****
(2) RX FAULT Pin 7 (NO), 8 (COM), 9 (NC) ****
(3) COM EQ FAULT Pin 1 (NO), 2 (COM), 3 (NC) ****
(4) TX ALARM #2 Pin 4 (NO), 5 (COM), 6 (NC) ****
(5) RX ALARM #3 Pin 7 (NO), 8 (COM), 9 (NC) ****
(6) PRIMARY ALARM Pin 43 (NO), 10 (COM), 27 (NC) ****
(7) SECONDARY ALARM Pin 44 (NO), 11 (COM), 28 (NC) ****
(8) DEF MAINT ALARM Pin 17 *****
* IDR only.
** IBS only.
*** D&I only.
**** A connection between the common and N.O. contacts indicate no fault/alarm.
***** Signal is open collector high impedance if faulted.