Negative Input test - TM-55-4920-430-130125

TM 55-4920-430-13

b. Negative Input test.

(1) Set the SERVO SIMULATION ROLL switch to OPERATE.

(2) Connect the negative terminal of No. 1 power supply to one side of the decade resistor. Con-

nect the other side of the decade resistor to receptacle pin J1-NN, connect the positive side of the power

supply to receptacle pin J1-MM. Set the decade resistor to 1000 ohms.

(3) Connect the digital multimeter across the decade resistor, positive input of the multimeter to

negative output of the power supply. Set the multimeter to the 2 vdc range.

(4) Adjust the output of No. 1 power supply for -0.10 volt on the digital multimeter.

NOTE

This applies approximately 0.1 milliampere input current through J1-

NN.

(5) Disconnect the digital multimeter from No. 1 power supply and the decade resistor.

(6) Connect the digital multimeter set to read 20-volt dc, to receptacle pinJ1-s (line) and J3-AA.

The digital multimeter shall indicate less than 0.03 volt ac.

(7) Connect No. 2 power supply across receptacle pins J3-A (+) and J1-C.

NOTE

When a test includes a requirement that an ac voltage be in-phase or

out-of-phase, oscilloscope channel A must be connected across the

digital multimeter. Oscilloscope channel B must be connected to the ac

source and the oscilloscope externally triggered from the ac source.

(8) Adjust the output of No. 2 power supply to +28 volt dc. Monitor the Feedback No. 1 output on

the digital multimeter. Within 1.6 to 2.4 seconds, the multimeter shall indicate 3.0 volt ac, in-phase.

The indication shall rise to 4.45 to 5.05 volt ac, in-phase.

(9) Se the ROLL switch to RESET. The multi meter shall indicate less than 0.03 volt ac.

(10) Disconnect the positive lead of the digital multimeter from receptacle pin J l-s. Connect it to

receptacle pin J l-j.

(11) Set the ROLL switch to OPERATE. Monitor the Feedback No. 2 output on the digital mul-

timeter. Within 1.6 to 2.4 seconds, the multimeter shall indicate 1.5 volts ac in-phase. The indication

shall rise to 2.18 to 2.58 volt ac in-phase.

(12) Set the ROLL switch to RESET. The multimeter shall indicate less than 0.03 volt ac.

(13) Disconnect the positive lead of the digital multimeter from receptacle pin J1-j. Connect it to

receptacle pin J l-m.

(14) Set the ROLL switch to OPERATE. Monitor the Feedback No. 3 output voltage on the

digital multimeter. Within 1.6 to 2.4 seconds, the multimeter shall indicate 1.5 volt ac, in-phase. The

indication shall rise to 2.18 to 2.58 volt ac, in-phase.

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