Marantz 250 - Required Test Equipment for Servicing

TEST
EQUIP
MENT
REQUIRED
FOR
SERVICING
ет
Table
1
lists
the
test
equipment
required
for
servicing
the
Model
250
Stereo
Power
Amplifier.
The
watt-
meter,
AC
voltmeter,
and
variac
may
be
assembled
as
a
test
fixture
as
shown
schematically
in
Figure
3,
and
the
load
resistors
and
AC
ammeter
may
be
assembled
into
a
second
test
fixture
as
shown
in
Figure
4.
Item
Manufacturer and Model No.
(or equivalent)
Distortion Analyzer
Hewlett Packard, Model 331A or 333A
Audio Oscillator
Weston Model CVO-100P (NOTE :
Less than 0.02 percent residual
distortion is required.)
Oscilloscope
Tektronix, Model 503; Data, Model 555
VTVM
RCA Senior Volt-Ohmyst, Model WV-98C
AC Wattmeter
Simpson, Model 390
AC Ammeter
(0 to 10 amps)
Commercial Grade
Line Voltmeter
(0 to 150 vac)
Commercial Grade
Variable Autotransformer
(0 to 140 vac, 10 amps)
Powerstat, Model 1168
Shorting Plug
Use phono plug with 600 ohms across
center pin and shell.
Power Supply Bleeder
Resistor (10 ohms at 1 W)
Commercial Grade
Output Load Resistor
(8 2 +9.5%, 250 W)
Commercial Grade
Output Load Resistor
(49 +0.5%, 250 W)
Commercial Grade
Provides 4-ohm load for
amplifier output termination.
Output Load
Capacitor (0.5 mfd)
Mylar
AC Power Control Box
Optional Item. Fabricate in
accordance with Figure 3.
Amplifier Output
Load Box
Optional item. Fabricate in
accordance with Figure 4.
Measures distortion and voltage
of amplifier output.
Sinewave and squarewave
signal source.
Waveform analysis and
troubleshooting
Voltage and resistance
measurements.
Monitors primary power
consumption of amplifier.
Monitors amplifier output
under short circuit condition.
Monitors potential of primary
power to amplifier.
Adjusts level of primary
power to amplifier.
Shorts amplifier input to
eliminate noise pickup.
Discharges power supply filter 2
capacitors prior to disassembly
or resistance measurements.
Provides 8-ohm load for
amplifier output termination.
Provides capacitive load for *
instability checks.
Monitors and controls primary
power for amplifier.
Provides various amplifier loads
and can monitor shorted output.