Component Interface Input Logic Discrete Signal Test (CRC)

TM 55-4920-430-13

4-58. Component Interface Input Logic Discrete Signal Test (CRC). The logic discrete input

signal include an indicator light and a resistive load for each discrete output signal from the AFCS

computer.

a. Resistance Measurement.

(1) Set TESTER POWER switch to OFF. Set AFCS POWER 28 vdc switch is ON.

(2) Remove the following indicator lamps.

(a) CCDA Clutch Indicator DS17

(b) CCDA Brake Indicator DS18

(d) HYD SOL Indicator DS20

(e) ERECT Cutout Indicator DS21

(f) HDG Enable Indicator DS22

(g) DASH ANN Indicator DS23

(3) Set the digital multimeter FUNCTION switch to ohms. Set the RANGE switch to 2K ohms.

Make the following resistance measurements.

(a) Connect the multimeter leads between receptacle pins J l-c and Jl-C. The multimeter shall

indicate 294 to 306 ohms. Disconnect multi meter.

(b) Connect test leads to receptacle pins J1-b and J1-C. The multimeter shall indicate 294 to

306 ohms. Disconnect the multimeter.

cate 282 to 294 ohms. Disconnect the multi meter.

(d) Connect the multimeter leads between receptacle pins J3-S and J l-A. The multimeter shall

indicate 294 to 306 ohms. Disconnect the multi meter.

(e) Connect multimeter lead between receptacle pins J3-u and J1-A. Measure the resistance

between receptacles. The. multimeter shall indicate 700.7 to 729.3 ohms. Disconnect the multimeter.

(f) Connect the multimeter lock to receptacle pins J1-V and J1-A. The multimeter shall indicate

900 to 1100 ohms. Disconnect the multi meter.

(4) Set the digital multimeter RANGE switch to 20K ohms.

(5) Connect multimeter leads between receptacle pins J3-Z and J l-A. The multimeter shall indi-

cate 9K to 11K ohms. Disconnect multi meter.

b. Indicator Light Test.

(1) Install the following indicator lamps.

(a) CCDA Clutch Indicator DA17

(b) CCDA Brake Indicator DS18

(d) HYD SOL Indicator DS20

(e) ERECT Cutout Indicator DS21

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