BEARING INDICATOR Zero

TB 11-6625-821-35

oscilloscope.

(d) Adjust the horizontal gain of oscilloscope for a 4-centimeter horizontal trace,

centered on the horizontal axis.

(e) Reconnect the vertical lead to oscilloscope.

(f) A 1-to-1 Lissajous pattern should be observed on oscilloscope. If the top of

the pattern is tilted into the upper right-hand quadrant, the null obtained in (3) above was

the correct null. Readjust resolver B1 for the null obtained in (3) above, and proceed to (5)

below

(g) If the top of the 1-to-1 Lissajous pattern is tilted into the upper left-hand

quadrant, rotate resolver B1 approximately 175 degrees clockwise as viewed from the rear

of the LOOP SIMULATOR, and adjust for another null indication on voltmeter.

(5) Tighten the three resolver clamps holding resolver B1 to the resolver housing.

(R)

(6) Disconnect the equipment, and replace the LOOP SIMULATOR.

10. BEARING INDICATOR Zero

a. Performance Procedure

NOTE

Disassembly and manual rotation of the indicator as prescribed

in the following procedure is not recommended for

inexperienced personnel working outside proper instrument

repair facilities. Perform paragraph 11 first. If improper

indications in paragraph 11 are observed, proceed as follows or

obtain assistance as required to open and adjust this indicator.

(1) Set the DC POWER switch of the unit under test to OFF.

(2) Remove the BEARING INDICATOR and Direction Finder Control C-6899/ARN-

83 from the unit under test. Remove cable from bearing indicator and leave cable to

direction finder control intact. Set DF control to ADF.

(3) Remove the front cover from the BEARING INDICATOR by removing the

screws located around the perimeter on the rear side of the housing.

(4) Set the RECEIVER-CONTROL switch of the unit under test to CONTROL.