Marantz PM500 - Page 5

left
AUX/TAPE
3.
Adjust
the
oscillator
level
for
a
23.6V
VTVM
reading.
Adjust
RX39
(L-CH)
so
that
the
power
meter
indicates
70W.
Carry
out
the
same
adjustment
for
the
right
channel
(RX40).
6. TEST EQUIPMENT REQUIRED FOR SERVICING
Table 1 lists the test equipment required for servicing the
PM500/PM700 Stereo Console Amplifier. The wattmeter,
AC voltmeter, and variable autotransformer may be
2.
assembled as a test fixture as shown schematically in
Figure 1. The load resistors and AC ammeter may be
assembled into a second test fixture as shown in Figure 2.
7, PERFORMANCE VERIFICATION
3.
TEST PROCEDURE
A. TEST EQUIPMENT
Refer to Table 1 for required test equipment.
B. PRELIMINARY PROCEDURES
Make the test setup shown in Figure 1 with the
instrument controls set in the following positions:
Line Switch OFF
Variable-line
switch
Variable
Wattmeter Switch ON
Variable
Autotransformer
0
V
(fully
CCW)
Load
8
ohms
(0.5
mfd—OF
F)
Audio
Generator
1
kHz
Output 5 V range
Gain Minimum
AC Voltmeter 30 V range
Make
sure
that
connections
between
the
resistive
load
and
the
system
terminals
of
the
PM500/PM700
have
negligible
resistance
when
compared
with
the
resistance
of
the
load
itself.
Appreciable
resistance
in
wiring
adds
to
the
total
load,
resulting
in
inaccurate
measurements
of
output
power.
Connect
amplifier
output
to
load
and
connect
AC
cord
to
line
power.
Connect
shorting
plugs
to
the
Phono
input
jacks
of
the
PM500/PM700.
Table
1.
Test
Equipment
Required
for
Servicing
item Manufacturer and Model No.
Distortion Analyzer
Audio Oscillator
AC Voltmeter
Sound Technology Model 1700B
Tektronix Model T932
il
Gaoillestope Philips Model 3232
Circuit Tester
Fluke Model 8000 ‘’Digital’’ Simpson
Deore Model 313, Triplet Model 801
Use
Distortion Measurements
Sinewave and squarewave signal source
voltage measurements (AC)
Waveform analysis and trouble shooting and
ASO alignment
Trouble shooting
Voltage measurements (DC)
AC Wattmeter ‘Simpson Model 1379
sf
a
Monitors primary power to amplifier
AC Ammeter Commercial Grade (1 ~ 10 A)
. “ge . . 7.
Monitors amplifier output under short circuit
condition
Line Voltmeter Simpson Model 1359
Monitors potential of primary power to
amplifier
Superior Electronic Co.,
Variabl f
ee NeHUven giinleriney Powerstet Model 116B-10A
Adjusts level of primary power to amplifier
Shorting PI Use phono plug with 600 ohm
ort
baat across center pin and shell
Shorts amplifier input to eliminate noise
pickup
Output Load
Commercial Grade
(8 ohms, +0.5% 100 W)
Provides 8-ohm load for amplifier output
termination
Output Load
Commercial Grade
(4 ohms, +0.5% 100 W)
Provides 4-ohm load for amplifier output
termination
Output Load Capacitor
Mylar
(0.5 mtd) -
Provides capacitive load for instability checks
Optional Item. Fabricate in
AC Power Control Box . :
accordance with Figure 1
Monitors and controls primary power for
amplifier
es Optional Item. Fabricate in
Amplifier Output Load Box
—eeeeeeee lame
accordance with Figure 2
Provides various amplifier loads and can
monitor shorted output