TM 11-6625-828-12
b. Make sure that the RF OUTPUT 1 VOLT jack is
NOTE
capped with the 51-ohm termination cap chained to the
Be careful not to press the
front panel.
screwdriver
any
harder
than
c. Check to see that the crystal frequency tabs on the
necessary to engage the trimmer
front panel agree with the frequencies of the crystals
screw slots, as damage or false se
installed. The upper crystal corresponds with the A
tings may result.
position; the lower crystal corresponds with the B
position.
e. Set the MC switch to B and adjust the trimmers for
d. Use Power Cable Assembly CX-33/U to connect
the B crystal by carefully inserting a small screwdriver in
the SG-66B/ARM-5 to the 115-volt, 60-cycle power
the front panel PLATE B tuning hole and the GRID B
source. Allow the equipment to warm up for at least 5
tuning hole in turn, and adjusting the trimmers for a
minutes.
maximum indication on the RF meter.
NOTE
f. Adjust the RF LEVEL SET control until the RF
The S-66B/ARM will operate only from
meter needle is aligned with the meter scale red LEVEL
a 60-cycle power supply because of a
SET line.
synchronous motor the speed of
g. Set the MODULATION switch to 9960~. Adjust
which determines the frequency of
the 9960~ MOD control until the % M meter needle is
the generated modulation voltages.
aligned with the green line at the high (right hand) end of
the meter scale. This adjustment sets the 9960~
modulation level at 30 percent when the RF LEVEL SET
2-8. Initial Adjustments
control is adjusted to align the needle of the RF meter
After the preliminary adjustments have been completed,
with the red LEVEL SET line on the meter scale.
check and adjust the operating controls and indicators as
h. Set the MODULATION switch to 30 ~. Adjust the
described below.
30 ~ MOD control until the % M meter needle is aligned
a. Set the POWER-STAND BY switch to POWER.
with the green line at the high end of the meter scale.
See that the red indicator lamp lights and that the tone
This adjustment sets the 30 ~ modulation level at 30
generator motor start.
percent when the RF LEVEL SET control is adjusted to
NOTE
the RF meter red LEVEL SET line.
In addition to the bearing noise of the
NOTE
motor, a slight high-pitched (10-
Do not change the settings of the
kilocycle (kc)) whine may be heard
9960 ~ MOD and the 30 ~ MOD
This sound is characteristic of the
controls after the MODULATION
tone wheel and does not indicate
switch is set to the OMNI position.
bearing trouble.
Otherwise, an improperly modulated
b. Calibrate the % M meter pressing in the ZERO
output signal will result.
SET knob and rotating it to the left or right. The meter
i. Set the MODULATION switch to 90 ~. Adjust the
needle will move to the lower (left-hand) stop pin and
90 ~ MOD control until the % M meter needle is aligned
remain there for approximately 2 seconds. Hold the
with the redline on the upper scale of the meter. This
ZERO SET knob in until the needle returns to the vicinity
adjustment sets the 90~ modulation level at 20 percent
of the 0 marking. Rotate the knob to the left or right to
when the RF LEVEL SET control is adjusted to the RF
align the needle with the meter ZERO SET line.
meter red LEVEL SET line.
c. Calibrate the RF meter by pressing in on its ZERO
j. Set the MODULATION switch to 150~. Adjust the
SET knob and rotating it to the left or right to align the
150~ MOD control until the % M meter needle is aligned
meter needle with the ZERO SET line on the meter
with the redline on the upper scale of the meter. This
scale.
adjustment sets the 150~ modulation level at 20 percent
d. With the MC switch set to A, adjust the trimmers
when the RF LEVEL SET control is adjusted to the RF
for the A crystal by carefully inserting a small screwdriver
meter red LEVEL SET lie.
in the front panel PLATE A tuning hole and the GRID A
toning hole in turn, and adjusting the trimmers for a
maximum indication on the RF meter.
2-4
