 |
|||
|
|
|||
|
|
|||
| ||||||||||
|
|
 TM
11-6625-467-34
3-31. Despike Detector Adjustment
(7) Pull the shaft of interlock switch S12 to the
override position.
The test set contains two despike detector circuits;
(8) Adjust the 500 KC AMPL control on the
one detects the spiking circuit output amplitude and
test set for 15 millivolts on the ME-30A/U.
the other detects the spike amplitude of the AN/
(9) Disconnect the ME-30A/U from the INPUT
ARC-54 power supply. Perform the following pro-
and GRD terminals on the GR-1142-A and connect
cedures to adjust both circuits:
it to the FM terminals as shown by the dashed lines
a. Remove the test set from the case.
in figure 3-29.
-
b. U s i n g t h e m o d u l e e x t e n d e r b o a r d , e x t e n d t h e
(10) Adjust the 1 KC AMPL control on the test
high-voltage power supply circuit card HU5 above
set for a deviation of 9.5 kHz as read on the GR
the card cage.
1142-A and ME-30A/U.
c. Connect power to the equipment and set the
(11) Connect the ME-30A/U to pin 1 on the
POWER switch to ON.
audio amplifier/detector circuit card.
d. Pull the shaft of interlock switch S12 to the
(12) Adjust L1 on the audio amplifier/detector
override position.
circuit for a maximum reading on the ME-30A/U.
e. S e t t h e P O W E R S E L E C T O R s w i t c h t o
( 1 3 ) Push the PRESS TO TEST button and
DESPIKE.
readjust L1 for a minimum reading on the TEST
f. Connect the AN/USM-182A to J3 on the +28-
METER.
volt regulator card HU4.
g. Adjust the DE SPIKE AMPL control on the
NOTE
test set for a spike amplitude of 40 volts (including
the dc level above ground).
Leave the equipment connected to make
h. Push the PRESS TO MONITOR VOLTAGE
the discriminator output level adjustment
button and adjust R12 on the high-voltage power
in b below.
s u p p l y circuit card HU5 for a TEST METER
b. Discriminator Output Level Adjustment.
reading of 80 percent.
(1) Connect the ME-30A/U to pin 1 on the
i. Set the POWER switch to OFF and connect a
audio amplifier/detector circuit card.
j u m p e r between J4 and J6 on the high-voltage
(2) Adjust R40 on the audio amplifier,/detector
power supply circuit card HU5. Return the POWER
circuit card for 15 millivolts on the ME-30A/U.
switch to the ON position.
j. Set the CIRCUIT SELECTOR switches to
3-30. Despiking Circuit Duty Cycle
1030.
Adjustment
k. Push the PRESS TO MONITOR VOLTAGE
Perform the following procedures to adjust the spik-
button and adjust the DESPIKE AMPL control for a
ing circuit duty cycle for a ratio of 9 to 1:
reading of 80 percent on the TEST METER.
a. Remove the test set from the case.
l. Push the PRESS TO TEST button and adjust
b. Using the module extender board, extend the
R9 on the high voltage power supply circuit card
+28-volt regulator circuit card HU4 above the card
H U 5 for a reading of 80 percent on the TEST
cage.
METER.
c. Connect power to the equipment and set the
m. Remove the jumper connected in i above.
POWER switch to ON.
d. S e t t h e P O W E R S E L E C T O R s w i t c h t o
3-32. 30-MHz Oscillator Tuning Adjustment
DESPIKE.
Perform the following procedures to insure that the
e. Pull the shaft of interlock switch S12 to the
collector circuit of the 30-megahertz transistor is
override position.
tuned properly:
f. Connect the AN/USM-182A (oscilloscope) to
a. Remove the test set from the case.
pin 16 on the +28-volt regulator circuit card.
b. Connect power to the test set and set the
POWER switch to ON.
two of the positive pulses coincide with the 1st and
C . Using the module extender board, extend the
10th horizontal lines on the oscilloscope mask (fig.
h. Adjust R23 on the +28-volt regulator circuit
card so the trailing edge of the first positive pulse
coincides with the second horizontal line on the
oscilloscope mask.
i. Repeat adjustments in g and h above until no
Figure 3-30. Oscilloscope pattern of despiking pulses when
further adjustment is necessary.
despiking circuit iS properly adjusted.
3-48
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals