7. Synchro Transmitte. a. Performance Check
r
.
(1) Rotate the synchro control knob on the Test Instrument toward 0 until a null indication is obtained on the
voltmeter. As null is approached, continuously decrease ranges on the voltmeter until an absolute minimum indication is
obtained. The dial on the Test Instrument should indicate between 359.9 and 0.1 .
(2) Rotate the synchro control knob on the test instrument toward a 90 indication on the dial scale. A maximum
voltage should be obtained on the voltmeter when the dial indicates between 89.9 and 90.1.
(3) Rotate the synchro control knob on the Test Instrument to 180. A null indication should be obtained when the
dial indicates between 179.9 and 180.1.
(4) Rotate the synchro control knob on the Test Instrument to 270. A maximum voltage should be obtained on the
voltmeter when the dial indicates between 269.9 and 270.1.
b. Adjustments.
(1) Remove the Test Instrument rear panel.
(2) Rotate the synchro control knob on the Test Instrument to obtain a scale indication of exactly 0.
(3) Connect the voltmeter between the X and 26V 400 -H jacks on the Test Instrument. Connect a jumper wire
between the GND-C and Z jacks.
(4) Loosen the three screws which hold the synchro transmitter and rotate the body of the synchro transmitter until a
maximum voltage indication is obtained on the voltmeter. (approximately 37.8 volts).
(5) Disconnect the jumper wire and the voltmeter and connect the voltmeter between jacks X and Y.
(6) Rotate the body of the synchro transmitter (approximately 30) until a null indication is obtained on the
voltmeter.
(7) Tighten the three screws which hold the synchro transmitter. Be sure the voltmeter still indicates null when the
screws are tightened. (R)
(8) Repeat the performance check in a(1) through (4) above.
8. Final Procedure a. Deenergize and disconnect all equipment, and replace the rear panel, if removed for
.
adjustments.
b. In accordance with instructions given in TM 38-750, annotate and affix calibration DA Label 80 (US Army
Calibration System). When the Test Instrument cannot be adjusted within tolerance, annotate and affix DA Form 2417
(Unserviceable or Limited Use).
By Order of the Secretary of the Army:
BERNARD W. ROGERS
General, United States Army
Chief of Staff
Official:
J. C. PENNINGTON
Brigadier General, United States Army
The Adjutant General
Distribution:
To be distributed in accordance with DA Form 12-36A, Section II, literature requirements for
calibration procedures publications for SM-254/ASM.
GPO 944 877
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