Amplifier Card Test Circuit

TM 11-6625-646-15

network consisting of resistors R313, R312, and

of diode rectifier CR10 is filtered by capacitor C9 and

capacitor C201 to pin 19 of AMPLIFIER receptacle J71.

applied to load resistor R16 which is connected across

This circuit also furnishes ac reference voltage for the

the base and collector of transistor Q4. Twenty-seven

amplifier card of the demodulator-modulator card test

volts dc from the power supply of the test set is

circuit (para 1-28). Twenty-seven volts dc from the

connected through current limiting resistor R17 to the

power supply of the test set is connected directly to pin 7

junction of torquemotor simulator resistors R302 and

and through a decoupling network consisting of resistor

R303.

The opposite ends of these resistors are

R203 and capacitor C202 to pin 8 of AMPLIFIER

connected to the emitters of transistors Q3 and Q4.

receptacle J71; pins 1 and 12 provide the ground

With only the rectified reference voltage on the bases,

returns. These are the dc operating voltages for the

equal currents flow through the emitters and the

amplifier stages.

differential indicated by meter M1 is zero.

(2) When a test signal is present in the

b. Input Signal. Twenty-six volts ac from the

primary of interstage transformer T8, the signal will,

power supply of the test set is also connected to the

depending on its phase, add to the positive half-cycle of

primary winding of stepdown test signal transformer

reference voltage at diode CR9 or CR10 and subtract

T301 (on card A02V3064). The secondary winding is

from the positive half-cycle at the other diode. With

center tapped to ground and the opposite ends of the

unequal dc potentials applied to the bases, unequal

winding ale connected to phase-reversing CARD TEST

currents will flow through the emitters of transistors Q3

SIGNAL switch S6. Operating the switch to L or R

and Q4 and through resistors R303 and R302. The

connects the selected phase of the test signal through a

direction and amplitude of the differential is indicated on

voltage divider network R308 and R309 (on card

function meter M1.

A02V3064) to the input of the amplifier through pin 6 of

receptacle J71.

1-29. Amplifier Card Test Circuit

(fig. 1-5)

Figure 1-2. Actuator-simulator card schematic

The amplifier card test circuit furnishes operating

diagram.

voltage and an input test signal to the card under test

and connects the output of the card to the loading and

(Located in back of manual.)

metering circuits.

a. Operating Voltage. Twenty-six volts ac from the

power supply of the test set is connected through an RC

(Next printed page is 13)