Comtech EF Data SDM-650B - Manual (Page 169)

SDM-650B Satellite Modem Data Rates and Filters
Rev. 6 A–3
6. Re-install the daughter board hold-down screws (Figure A-1). Re-insert the
modulator into the chassis.
7. Remove the demodulator card (AS/0778) using the white card ejectors.
8. With a Phillips screwdriver, remove the four screws holding down the daughter
card. See Figure A-2 for location of the hardware.
9. Remove the daughter card (AS/0362) from the demodulator.
10. Install the replacement daughter card (AS/0362) so that:
a. J1 on the daughter card lines up with J2 on the demodulator card.
b. J2 on the daughter card lines up with J3 on the demodulator card.
c. All four hold-down screws line up.
See Figure A-2.
CAUTION
If the filter is installed in the wrong position, the daughter card will
be damaged.
11. Re-install the daughter board hold-down screws (Figure A-2), and re-insert the
demodulator into the modem chassis.
12. Remove the M&C board, and remove JP6 (battery ON/OFF). Short the leads of
capacitor C12. Replace the battery jumper to the ON position, and re-insert the
M&C card into the modem.
13. Turn ON the power switch.
14. Go to the Utility menu on the front panel, and program the time, day, TXA, TXB,
TXC, TXD, RXA, RXB, RXC, and RXD to the new data/code rates.
Note: The data/code rate assignment in the Utility menu must match the filter
assignment on the daughter card. Each daughter card is labeled with the filter
assignment (A, B, C, and D) and associated symbol rate. Example: The label for
a 64 kbit/s, 7/8 rate, QPSK filter is 36.57.
15. Go to the Config menu on the front panel and select the desired TX and RX rate.
Turn ON the RF output.
The hardware change is complete.