1.

ÑTake gyrohorizon off an aircraft and switch it to a source of three-phase sine wave 36 V current with frequency of 400Hz, keeping order of phases connection (A B Ñ). Correctness of phases connection on ÀÃÊ and LUN devices can be checked by operation of the built-in turn indicator, turning working gyrohorizon on the table, the tag of turn indicator should turn to the left at counter-clockwise turn and to the right at clockwise turn. In case of opposite reaction it is necessary to interchange any two wires from 3 ones of power supply of a gyrohorizon. Correctness of connection on other devices is checked by operating of a system of correction of a vertical. For this purpose after spinup of the device (1,5-2 min) turn in arrested state the device on roll and pitch on 15-20 degrees and unarrest after that, put the device on a table and see operation of correction mechanism. At correct connection correction mechanism will start to reduce roll and pitch with angular velocity of 3-10 degrees in one minute. At wrong connection value of roll and pitch will increase with the same speed.

2.

Switch on power supply and untwist gyroscope during 1,5-2 minutes. In arrested state turn the device around horizontal cross-section axis on angle 10 - 20 degrees and unarrest the device. Put the device on a table in horizontal position and measure angular velocity of returning of a gyroscope in vertical position. It should depend on adjustment and type of the device within the limits of 2-10 degrees in one minute. Then repeat procedure, turning the device around horizontal cross-section axis in other side, and turning around longitudinal axis of the device (simulating turn of gyroscope axes) to the left and to the right. Angular velocity should be similar in all 4 checks. If in result of checks a gyroscope does not turn in vertical on roll or pitch or if it stops at any value, distinct from vertical, then the device requires repair.