Marantz PM400 - C. Total Hum and Noise Test; D. Maximum Power Output; E. Harmonic Distortion Test; 8. Voltage Conversion

TOTAL
HUM AND
NOISE
TEST
_
With
shorting
plugs
connected
to
the
Phono
input
jacks
and
an
8
ohm
resistive
load
connected
across
the
speaker
system
output
terminals,
connect
a
dis-
tortion
analyzer
across
the
load.
NOTE:
If
the
distortion
analyzer
does
not
contain
a
built-in
voltmeter,
an
AC
VTVM
may
be
substituted.
.
Set
the
distortion
analyzer
controls
for
voltge
measurements
and
apply
power
to
the
amplifier.
Set
the
volume
control
fully
CCW.
Set
the
SELECTOR
switch
to
PHONO.
_
1
the
distortion
analyzer
indicates
more
than
2.0
mV
refer
to
the
trouble
analysis
section
of
this
manual.
_
Set
the
volume
control
fully
CW.
If
the
distortion
analyzer
indicates
more
than
20
mV,
refer
to
the
trouble
analysis
section
of
this
manual.
MAXIMUM POWER OUTPUT
_
Connect
the
audio
oscillator
to
the
AUX
input.
Set
audio
oscillator
frequency
to
1
kHz.
Set
SELECTOR
switch
to
AUX.
_
With
the
distortion
analyzer
connected
across
the
output
load
(8-ohm),
set
the
analyzer
on
the
30
VAC
scale.
.
Turn
the
analyzer
on
and
increase
the
audio
oscillator
output
to
150
mV.
The
AC
VTVM
should
read
17
VAC
(14.1
VAC
For
Model
PM250
only)
or
more.
10.
HARMONIC DISTORTION TEST
. Set the frequency of the audio oscillator and the
distortion analyzer to 20 kHz.
. Set the controls of the analyzer for voltage measure-
ment on the 30 volt scale.
. Adjust the audio oscillator output level until the
analyzer meter indicates 17 VAC. (14.1 VAC For
Model PM250 only)
. Switch the distortion analyzer to Set Level and
adjust SENSITIVITY for full scale reading on 0 ~ 1%
scale.
Measure the total harmenic distortion with the
analyzer and verify it is less than 0.05%.
NOTE:
Any parasitic oscillation in the amplifier will be
displayed on the oscilloscope when capacitance is
switched into the load.
. Switch the distortion analyzer back to SET LEVEL.
(Do not readjust sensitivity of analyzer.)
. Change the frequency of the audio oscillator and dis-
tortion analyzer to 1 kHz. Adjust audio oscillator
output for a full scale reading on the 0 ~ 1% scale.
. Measure the distortion, verifying it is no greater than
0.05%.
. Repeat steps 7 and 8, changing frequency to 20 Hz.
Distortion should be no more than 0.05%.
Check for parasitic oscillation; there should be none.
8.
VOLTAGE
CONVERSION
To
convert
the
unit
to
a
different
power
source
voltage,
change
the
position
as
illustrated
in
the
drawing
below.
CAUTION:
DISCONNECT
POWER
SUPPLY
CORD
FROM
AC
OUTLET
BEFORE
CONVERTING
VOLTAGE.
PLEASE
DO
NOT
DISASSEMBLE
THE
VOLTAGE
SELECTOR
ABSOLUTELY.
(T) (A) Versions
Note on safety:
(N) Version
The parts marked with A\ are important
parts on the safety. Please use the parts
having the designated parts number
without fail.
(P) Version