3.
Replace C22 discrete component if the part is available.
(5)
Perform equipment settings as follows:
(a)
DC POWER: ON.
(b)
AN/URM-127 audio oscillator set for 1 kHz, at 2.75 volts.
(6)
Measure the signal amplitude between terminal AR2-4 and AR2-5. The normal
indication should be 10-20 mv RMS. If you have a normal reading, this tells you to replace
AR2 and then repeat the functional test.
(7)
Measure the amplitude of the signal between the white and red terminals of T3
(headset amplifier input transformer secondary). The normal indication should again be 10-20
mv RMS. A normal reading would tell you to replace T3 and repeat the functional test.
(8)
Perform equipment settings as follows:
(a)
MK-994/AR DC POWER: OFF.
(b)
Remove audio signal.
(9)
Using a ME-26, measure the continuity between J19-A (MK-994/AR) and COMM
CONT 2, TB1-17. Normal reading: Short circuit; an abnormal reading would mean for you to
replace faulty wiring and then repeat the functional test.
Again, take your ME-26 and measure the resistance between J-19A (MK-
994/AR) and COMM CONT 2, TB1-16. The normal reading: 3,300 to 3,700 ohms. An
abnormal reading would mean for you to replace R32 and repeat the functional test.
(10)
Turn your VOL control fully clockwise and measure the resistance between J-
19A and COMM CONT 2, TB1-18.
(a)
A normal reading: 30-50 ohms (VOL control full clockwise).
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