Self-Test Circuit

11-6625-2843-14

AMPLIFIER GAIN control R201 rotated fully clock-

voed indicator control transformer until the error sig-

wise. With this test setup, the stators of the transmit-

nal to the servoamplifier is at null, At this point, the in-

ter under test and the control transformer of indicator

dicator rotor is at correspondence with the rotor of the

B202 are connected back to back; and the rotor of the

differential under test.

transmitter under test, servoamplifier A201, and the

5-11. Self-Test Circuit

fixed-phase winding of the low-inertia motor are

a. The self-test circuit (fig. FO-3) is enabled by

energized by 26 volts. This test configuration is essen-

TEST SEL switch S203 at TRANS, AMPLIFIER

t i a l l y the same as that of the transmitter test circuit

G A I N control R201 rotated fully clockwise, and test

for servoed indicators (para 5-5 and fig. 5-6), except for

plug H (QB83704-1), which shorts pins A, B, and D of

a functional exchange between the indicator and

connector J201 to pins E, F, and H, respectively. With

transmitter. In the present test, servoed indicator B202

this test setup, the circuit is functionally identical with

is the reference for the transmitter under test; and in

the indicator test setup for transmitters (para 5-7 and

the transmitter test circuit, transmitter B201 is the

fig. 5-6), except the transmitter under test is replaced

reference for the indicator under test.

i n the self-test circuit by transmitter B201. Thus, an

indicator track of the transmitter within 15 minutes

5-10.

Indicator

Test

Circuit

for

Differen-

assures proper operation of transmitter B201, indica-

tials

tor B202, and servoamplifier A201.

The indicator test circuit for differentials (fig. FO-2) is

b. With TEST SEL switch S203 set at DIFF, the cir-

enabled by TEST SEL switch S203 at DIFF and

cuit is essentially the same as the indicator test circuit

AMPLIFIER GAIN control R201 rotated fully clock-

for differentials (para 5-8 and fig. 5-8), except in the

wise. With this test setup, the stator of indicator B202

present test setup, the stators of locked synchro B203

and a stator of the differential under test are con-

and indicator B202 are connected back to back. Thus,

nected back to back, and the stator of locked synchro

with the TEST SEL switch at DIFF, an indicator drive

B203 and the remaining differential stator are con-

to 0 0.1 degree assures proper operation of lock syn-

nected back to back, and the rotor of locked synchro,

chro B203.

servoamplifier A201 and the freed-phase winding of

indicator B202 are energized by 26 volts. The stator

5-12. Servoamplifier Circuit

o u t p u t of the locked synchro excites the differential

Servoamplifier circuit (fig. 5-7) is used in test circuits

under test, and the output of the differential excites

that contain a servoed indicator. As such, it boosts the

t h e stator of the test set servoed indicator control

signal applied to the rotor of the servoed indicator con-

transformer. The signal induced into the indicator

trol transformer by the amount required by the low-in-

rotor is amplified by the servoamplifier and applied to

ertia drive motor. The servoamplifier is made up of a

the variable-phase winding of the law-inertia motor of

full-wave, center-tapped silicon rectifier, two dual

indicator B202. The motor rotates and drives the ser-

triodes and an output transformer.

5-8