Dc Power Supply Circuit Test

TM 11-6625-646-15

(up) position. The vtvm should indicate between 24.5

c. Connect the dc power supply to TEST 66

and 27.5 volts. The FUNCTION meter should indicate

CHANGE 4 POINTS A (positive) and C. Adjust the dc

between +8 and +12 volts.

supply to 24 volts. The FUNCTION meter should

c. Set the 115V 400 ~ POWER switch to off

indicate between +7 and +10. Disconnect the dc supply.

(down) position.

d. Turn the FUNCTION switch to AC PWR.

d. Disconnect the vtvm.

e. Connect the ac power supply to TEST POINTS

e. If any indication is not as specified, take

B and C. Adjust the ac supply to 26 volts. The

FUNCTION meter should indicate 0. Disconnect the ac

corrective action and repeat the applicable steps.

power.

7-6. Dc Power Supply Circuit Test

f. Turn the FUNCTION switch to PEDAL POT.

EXCITATION.

a. Turn the FUNCTION switch to DC PWR.

g. Connect the dc power supply to TEST POINTS j

b. Connect the multimeter between AMPLIFIER

(positive) and f. Adjust the dc supply for +40 volts. The

CARD TESTER receptacle pin 7 (positive) and 12.

FUNCTION meter should indicate between +8 and +12.

Adjust the multimeter to measure 30 volts de.

WARNING

c. Set the 115V 400 ~ POWER switch to on (up)

Be careful when using the dc power

position.

The FUNCTION meter should indicate

supply. Above 45 volts its output is

between +8 and +12. The multimeter should indicate

dangerous to life.

between 25 and 29 volts.

d. Increase the 400-cycle supply voltage to 120

volts. The multimeter indication should not change.

h. Turn the FUNCTION switch to PEDAL POT.

OUTPUT.

NOTE

i. Connect the multimeter between TEST POINTS

If the 400-cycle supply is not

h (positive) and C. Adjust the multimeter to measure 30

adjustable, connect power to the test

volts dc.

set through an autotransformer for

j. Turn the PEDAL POT.

control fully

this test.

counterclockwise.

The FUNCTION meter should

indicate a minimum of +16.

WARNING

k. Turn the PEDAL POT. control clockwise until

careful

when

using

the

the FUNCTION meter indicates +10. The multimeter

autotransformer or power supply.

should indicate between 9 and 11 volts.

Above 45 volts its output is

l. Turn the PEDAL POT. control clockwise until

dangerous to life.

the FUNCTION meter indicates 0. The multimeter

should indicate 0.

e. Set the 115V 400, POWER switch to off (down)

m. Reverse the multimeter connections at TEST

position.

POINTS C and h.

f. Disconnect the multimeter.

n. Turn the PEDAL POT. control fully clockwise.

g. If any indication is not as spe cified, take

The FUNCTION meter should indicate a minimum of -

16.

corrective action and repeat the applicable steps.

o. Turn the PEDAL POT. control counterclockwise

7-7. Metering Circuits Tests

until the FUNCTION meter indicates -10.

The

multimeter should indicate between 9 and 11 volts.

a. Remove the amplifier card from TS-1894/ASM

receptacle J69.

p. Turn the FUNCTION switch to INTLK.

b. Turn the FUNCTION switch to DC PWR.

q. Connect the dc power supply to TEST

CHANGE 4 66