Comtech EF Data SDM-100A - Manual (Page 148)

Maintenance SDM-100A Satellite Modem
5–6 Rev. 0
5.1.4 Test Points
The modem does not have accessible test points. When troubleshooting is required at
board level, the cover must be removed.
The following is a list of test points located on the PCB, and a description of the signal
that is to be present under normal operation.
5.1.4.1 Demodulator/M&C/Interface Test Points
TP 41 SYMBCK Symbol Clock
TP 37 DP1 Constellation I Test Point
TP 38 DP2 Constellation Q Test Point
TP 29 GND Ground
TP 34 DATCLK Data Rate Clock
TP 4 GND Ground
TP 3 +5V Plus 5 Volt
TP 12 SD Send Data
TP 13 TT Terminal Timing (Transmit Clock)
TP 14 RD Receive Data
TP 15 RT Receive Timing
TP 16 GND Ground
TP 11 GND Ground
TP 31 IF SYNTH REF
(R143 must be populated) IF Synthesizer Reference
TP 36 RX CLK Buffer Output Clock
TP 28 AGC CNRL Digital AGC control
TP 26 AGC DRV Analog AGC drive
TP 18 I I channel Analog RF Output
TP 19 Q Q channel Analog RF Output
TP 25 GND Ground
TP 20 Q OFF Analog Q channel DC offset control
TP 24 I OFF Analog I channel DC offset control
TP 21 Q CHAN Q channel Analog anti-alias filter output
TP 22 I CHAN I channel Analog anti-alias filter output
TP 27 Q A/D IN Q channel Analog to Digital input
TP 30 I A/D IN I channel Analog to Digital input
D9 OVFL Buffer Overflow LED
D10 UNFL Buffer Underflow LED
D11 XDN/PG XILINX Done Programming LED