TM 11-6625-596-12
c.
Earphones,
Receivers,
and
Headsets.
panel controls as listed in TB 11-6625-596-12/1. The
panel meter pointer should read on the red midscale line;
if it does not, adjust the METER SENSITIVITY
front panel controls as listed in TB 11-6625-596-12/1.
CALIBRATE control to bring it to midscale. Place the
The panel meter pointer should read at midscale; if it
sound-powered telephone in the coupler (fig. 1-3), with
does not, adjust the METER SENSITIVITY CALIBRATE
the receiver unit of the telephone squarely over the test
control to bring the panel meter pointer to the red
microphone and the microphone squarely over the test
midscale line.
Insert the earphone plug-in jack
loudspeaker. It is important that the receiver is squarely
1A2A14J6, J7, or J8 on electrical test panel 1A2A14 (fig.
Tape the
positioned over the test microphone.
5-1). If the plug does not fit or there is none, connect the
microphone switch on while testing. To test, depress the
earphone leads to the EARPHONES terminals. Square
the earphone unit over the screen of the test
1 LOW button. The panel meter pointer should read on
microphone, and secure it in place with the clamping
the good scale, given in the pertinent table for the
fixture. To test, depress the 1 LOW button, the 2
transducer being tested. Perform the stopping procedure
CENTER button, and the 3 HIGH button, in turn. The
panel meter pointer should read on the good scale.
2-17. Insulation Resistance Test
d.
WARNING
sets, headset-microphones, chest sets, handset-
When the INSULATION RESISTANCE switch
headset, head and chest sets, etc., are tested as follows:
is depressed, up to 100 volts may be present
Test the transducers in a handset by testing the
on TEL LINE terminals L1 and L2.
individual items as set forth in a, b, and c above. Refer
to the pertinent tables in TB 11-6625-596-12/1 for the
LEVEL and VALUE control setting and the good scale
TEL LINE terminals L1 and L2 to the insulation to be
readings in each frequency band for the units listed.
Adjust the INSULATION RESISTANCE CALIBRATE
NOTE
control so that the panel meter pointer reads on the red
Tape the microphone switch on while
midscale line. To test, depress the TEST button. The
testing.
panel pointer should read at midscale or below. Perform
e.
Narrow-Band Earphones, Receivers, and
2-18. Continuity Test
Set the front panel controls as listed in TB 11-6625-596-
12/1. The panel meter pointer should read on the red
the CONTINUITY TEST LEADS terminals to the circuit
midscale line; if it does not, adjust the METER
under test. If the circuit has a dc resistance of 10 ohms
SENSITIVITY CALIBRATE control to bring the meter
or less, the buzzer will sound and the continuity test lamp
pointer to midscale. Insert the earphone plug-in jack
1A2A14J3 on electrical test panel 1A2A14 (fig. 5-1). If
the plug does not fit, or there is none, connect the
2-19. Stopping Procedure
earphone leads to the EARPHONES terminals. Square
a.
To stop the TS-716/U, turn the power switch to
the earphone unit over the test microphone. Secure it in
OFF.
place with the clamping fixture. To test, depress the 4
NARROW BAND button. The panel meter pointer
b.
Return the front panel controls to the positions
should read in the good scale indicated in the pertinent
listed below. This will prevent possible damage to the
table for the unit being tested. Perform the stopping
TS-716/U if the power is turned on without observing
the proper starting procedure.
f.
Sound-Powered Telephones.
Perform the
2-11