TM 11-6625-596-12
panel meter pointer reads on the red midscale line. The
second part of the test is to depress the SHORT LINE
2-16. Frequency Response and Sensitivity
button. The panel meter pointer should read between 40
Tests
a.
Dynamic Microphones. Perform the starting
c.
Receive Varistor Test. Perform the starting
listed in TB 11-6625-596-12/1. The panel meter pointer
should read on the red midscale line; if it does not, adjust
listed in TB 11-6625-596-12/1. Remove the receiver
the METER SENSITIVITY CALIBRATE control to bring
the pointer to midscale. Insert the microphone plug-in
connected in the handset. Connect the ARTIFICIAL
jack lA2A14J7, J9, or J11 on electrical test panel
RECEIVER terminals to the telephone handset wires that
1A2A14 (fig. 5-1). If the plug does not fit, or if there is
have been removed from the receiver. Connect TEL
no plug, connect the microphone with leads to the
LINE terminals L1 and L2 to the corresponding terminals
MICROPHONES OTHER TYPES terminal. Position the
on the telephone set. Depress the LONG LINE button
microphone unit squarely over the screen of the test
and adjust the METER SENSITIVITY CALIBRATE
loudspeaker. Tape the microphone switch on while
control so that the panel meter pointer reads on the red
testing Secure the microphone with the clamping fixture.
midscale line. To test, depress the SHORT LINE button.
To test, depress the 1 LOW button, the 2 CENTER
The panel meter pointer should read on the green scale.
button, and the 3 HIGH button, in turn. The meter
pointer should read on the good scale for the particular
frequency band used for testing the microphone as
2-14. Ringer Tests
indicated in the pertinent table. Perform the stopping
TEL LINE terminals L1 and L2 to the ringer. If the ringer
is installed in a telephone set, connect TEL LINE
b.
Carbon Microphones. Perform the starting
terminals L1 and L2 to the corresponding terminals of the
telephone set. Depress the proper RINGER button
listed in TB 11-6625-596-12/1. The panel meter pointer
(2400, 5300, or 12000) according to the instructions in
should read on the red midscale line; if it does not, adjust
TB 11-662-596-12/1 or in the technical manual of the
the METER SENSITIVITY CALIBRATE control to bring
telephone set. The ringer should ring with satisfactory
the pointer to midscale. Insert the microphone plug-in
loudness.
Perform the stopping procedure (para 2-
receptacle lA2A14Jl, J5, or J6 on electrical test panel
19).
lA2A14 (fig. 5-1). If the plug does not fit, or if there is no
plug, connect the microphone with leads to the
2-15. Telephone Hand Generator Test
MICROPHONES CARBON terminals. Tape the
microphone switch on while testing. Shake the
the HAND GENERATOR button. The panel meter
microphone vigorously. Position the microphone unit
pointer should read 0. Connect TEL LINE terminals L1
squarely over the screen of the test loudspeaker, and
and L2 to the generator. If a generator is installed in a
hold it in place by using the clamping fixture. Depress
telephone set, connect TEL LINE terminals L1 and L2 to
the READ MICROPHONE CURRENT button and adjust
the corresponding terminals of the -telephone set. Crank
the MICROPHONE CURRENT control until the panel
the generator at approximately 200 revolutions per
meter pointer reads midscale. Depress the READ
minute (normal rate). The panel meter pointer should
MICROPHONE CURRENT button two or three times
read 30 or above. For Hand Generator TA-1/PT,
until the current stabilizes. To test, depress the 1 LOW
depress the HANP GENERATOR button and make the
button, the 2 CENTER button, and the 3 HIGH button, in
connections as given above; then depress the TEST
turn. The panel meter pointer should read on the good
button and squeeze the hand generator handle at the
scale indicated in the pertinent table for the particular
normal rate. The panel meter pointer should read 30 or
microphone being tested and for the frequency band
applicable. If the microphone fails the test, repeat the
test. Some carbon microphones fluctuate considerably.
Return the MICROPHONE CURRENT control to OFF
2-10