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BELL SYSTEM PRACTICES
AT&TCo Standard
SECTION 024-17 4-500
Issue 3, January 1975
KS-20449 AMPLIFIER
TESTS AND ADJUSTMENTS
CONTENTS
PAGE
1.
GENERAL
.
.
.
1
2.
RECOMMENDED TEST EQUIPMENT
1
3.
PREPARATION
1
4.
GAIN-FREQUENCY TEST
2
5.
POWER OUTPUT TEST
2
6.
AGC COMPRESSION RANGE TEST
3
7.
NOISE TEST
. .
.
.
.
.
4
1.
GENERAL
1.01
This section outlines the tests to be performed
on the KS-20449 Ll amplifier. The amplifier
has an output of approximately
0.5 watt and is
used in such applications as military conference
arrangements,
Call Distributor Systems, and No.
300 Switching Systems.
1.02
This section is reissued to add KS-19774 L2
lO0PF capacitor (or equivalent) on the printed
circuit board, Fig. 3. This change eliminates
high-frequency oscillations and reduces noise from
the amplifier output signal.
This reissue does not affect the Equipment Test
List.
1.03
The tests outlined in this section should be
made to determine the performance of the
amplifier when clearing troubles.
These tests may
also be used to locate equipment troubles.
If the
tests indicate trouble that cannot be cleared, the
entire KS-20449 Ll amplifier should be returned
to the repair center.
2.
RECOMMENDED TEST EQUIPMENT
r
2.01
The following items of test equipment are
required
for tests
on the KS-20449 Ll
amplifier. If the specified equipment is not available,
a substitute
which is electrically equivalent may
be used.
1-Hewlett-Packard Model 200 CD signal generator,
or equivalent
1-5A attenuator, or equivalent
2-Hewlett-Packard
Model 400 AC voltmeter, or
equivalent
1-Tektronix*
Model 515A oscilloscope,
or
equivalent
2-600-ohm
resistor,
+
1 percent,
1 watt
noninductive
Test cords and clips as required.
*Registered trademark of Tektronix, Inc.
3.
PREPARATION
3.01
All ac-operated test equipment should be
allowed to warm up sufficiently
before
beginning any tests. This is important since it has
a bearing on the stability of the equipment and
accuracy of the tests.
All test equipment should
be calibrated before beginning the tests.
3.02
The amplifier should be removed from service
before testing.
The signal input and the
amplifier output should be disconnected, or opened,
at the most convenient point.
Record amplifier
options and connections for use in restoring amplifier
to service.
Note:
Unless absolutely necessary, wire-wrap
terminations should
not
be disturbed.
3.03
A good ground
should be connected
to
terminal 21 of TBl to reduce the possibility
of induced noise.
© American Telephone and Telegraph Company, 1975
Printed in U.S.A.
Page 1
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