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RECOMMENDED TEST EQUIPMENTS
The following test equipments are recommended to completely test and align the Amplifier:
Line Voltage !solation Transformer
AC DC Multimeter.
e
e
e Accurately Calibrated AC Voltmeter.
e
Oscilloscope (Flat to 100 kHz Minimum)
e
Low-Distortion Audio Sine-Wave Generator
e Harmonic Distortion Analyzer
e Two (2) Load Resistors 8-ohms, 250 Watts
(Minimum Rating)
HARMONIC DISTORTION TEST
CAUTION:
Limit the following tests to no more than
ten
minutes
each.
Use
8-ohm
resistors,
with
a
minimum
power rating of 250 watts when connecting
a load across the SPEAKERS terminal.
CONTROL SETTINGS:
Unplug the AC power
cord and set the front panel
controls as follows:
e GRAPHIC
EQUIALIZER
positions.
controls
to
center
e MIC MIXING controls to SOURCE position.
e POWER switch to OFF
e SPEAKERS switch to SYSTEM-B
e FUNCTION switch to AUX
e TAPE MONITOR switch to SOURCE
e VOLUME control to MINIMUM position
e LEFT CHANNEL DRIVEN
ONE CHANNEL DRIVEN:
1) Connect a low distortion audio generator to LEFT
AUX
IN jack. Set generator frequency to 1 kHz
and output to minimum.
2) Connect
an
8-ohm
load
resistor
between
SPEAKERS SYSTEM-A LEFT and COM terminals.
Connect
a Harmonic
Distortion Analyzer and an
AC VTVM in parallel across the 8-ohm load.
3) Connect the AC power cord and set SPEAKERS
switch to SYSTEM-A.
Turn
VOLUME
control to
MAX.
4)
Increase
generator
output
for
45
Watts
RMS
(18.9
volts
across
the
8-ohm
load).
Harmonic
Distortion
Analyzer
should
measure
0.09%
distortion or less.
5) Repeat steps 1 through 4 for RIGHT CHANNEL.
BOTH CHANNELS DRIVEN
Connect
8-ohm
load
resistors across
LEFT
and
RIGHT
SPEAKERS
SYSTEM-A
terminals.
Adjust
generator output and "VOLUME"
control for 45 Watts at Left and Right Channels (18.9 volts across
the 8-ohm
loads). Harmonic
Distortion Analyzer should measure 0.09 % distortion or less at each
channel.
CAUTION:
This precision high-fidelity instrument should be serviced only by qualified
personnel, trained in the repair of transistor equipment and printed circuitry.
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