TM 11-6625-596-45
b. Depress NOISE GEN ADJ button 1A4S6A,
4-6.
Dial Speed Adjustment 1A3R15
and rotate NOISE GENERATOR control 1A4R12 until
needle of meter 1A4M1 is at the red CAL line.
c. Connect the vtvm between 1A3J2-D and
ground.
b. Adjust 1A3R15 until the period between the
d. Depress METER ADJ button 1A4S6S and
pulses (time from start to one pulse to start of next
adjust METER SENSITIVITY CALIBRATE control
pulse) is exactly 0.050 second.
1A4R14 on the front panel until an output voltage of 2.0
volts (+0.05 volt) root mean square (rms) is obtained.
The period (time from start of one pulse to start of
e. Adjust 1A3R16 until the panel meter reads
following pulse) should be exactly 0.100 second. The
at the red CAL line on meter 1A4M1. Lock the
pulse width should be .05 to .06 second, the exact width
potentiometer.
is not impcrtant.
d. Press DIAL SPEED button 1A4S6M.
4-5.
Adjust DIAL SPEED CALIBRATE control 1A4R17 until
1A2A14R1
and R2
meter 1A4M1 reads midscale. If the reading on 1A4M1
cannot be set to midscale, see trouble-shooting chart
(para 3-3b).
have been performed, place test micro-phone 1A2A4A4
directly over test loudspeaker 1A2A2 touching the
4-7.
Noise Generator Load/Driver Adjustment
screen and proceed as follows:
1A3R9
a. Set the front panel controls as follows:
Control
Position
a. Depress NOISE GEN ADJ button 1A4S6A
EARPHONES button 1A4S6G---------------
Depressed
and adjust NOISE GENERATOR CALIBRATE control
TEST CONDITION switch 1A4S9-----------
COUPLER
1A4R12 to obtain a red CAL line reading on meter
NOISE GENERATOR switch 1A4S3--------
DRIVER
1A4M1.
LEVEL control A 1A4AT1----------------------
10
b. Set TEST CONDITION switch 1A4S9 to
LEVEL control B 1A4AT2----------------------
8
COUPLER, NOISE GENERATOR switch 1A4S3 to
VALUE control C 1A4AT3----------------------
6
LOAD, and recalibrate noise generator (a above).
VALUE control D 1A4AT4---------------------
9
b. Press LOW button 1A4S5B and adjust
c. Turn NOISE GENERATOR switch 1A4S3
1A2A14R2 until meter 1A4M1 reads midscale.
to DRIVER. The needle of meter 1A4M1 should stay at
c. Press HIGH button 1A4S5D and adjust
the red CAL line.
1A2A14R1 until meter 1A4M1 reads midscale.
d. Adjust 1A3R9 until the needle of meter
d.
Press CENTER button 1A4S5C, meter 1A4M1
1A4M1 stays at the red CAL line when NOISE
should read midscale. Adjust 1A2A14R1 and R2 such
GENERATOR switch 1A4S3 is switched from LOAD to
that the reading on meter 1A4M1 is as near midscale as
DRIVER.
possible when the LOW, CENTER and HIGH buttons
are pressed.
4-2