User's Manual

SBS-900 Shore Based Radar Systems
Chapter 10: Corrective maintenance
KH-1602-2 issue 1: Standard SBS900 Systems Operator & Maintenance Handbook
Page 149 of 240
10.7.7 DTX-A295 quadrature buffer PCB
The DTX-A295 converts pulsed 90:1 or 180:1 Azimuth and HL inputs into 4096 Quadrature differential
signals. The board uses a small processor to multiply the incoming Azimuth pulses in accordance with
the rate of turn detected.
Inputs are opto-coupled for signal integrity and isolation purposes.
The PCA is powered by the power supply located within the transceiver enclosure and can operate
from an input of between +12V to 24VDC. The PCA generates all required DC rails from the input
voltage with all rails being isolated (including GND) from the input supply.
10.7.7.1 PCB layout and connector details
PL1
PL2
PL1
-
1
ACP1
PL2
-
1
+12V
PL1
-
2
nACP1
PL2
-
2
ACP1
PL1
-
3
ACP2
PL2
-
3
nACP1
PL1
-
4
nACP2
PL2
-
4
ACP2
PL1
-
5
ARP
PL2
-
5
nACP2
PL1
-
6
nARP
PL2
-
6
ARP
PL2
-
7
nARP
PL2
-
8
GND/ 0V
10.7.7.2 LEDs
D1 (Green): Processor status
Processor running (Normal)
Flashing at 1Hz
(0.5 sec ON and OFF)
No heading line LED ON for 2 seconds
No azimuth LED OFF for 2 seconds
Example: If the AZ OK but there is no HL then the LED will be ON for 2 seconds, OFF for
0.5 second, ON for 2 seconds etc.
D4 (Green): DC present
DC power ON ON
No DC power to PCB
OFF
PL1:
ACP &
ARP
IN
PL2:
ACP &
ARP
OUT
PL3
Programming
Download lead
SW1 & SW2
Not used in
normal service
PL4
Not used in
normal service
D1
D4