6
-----------·~
5.
Improper clipping
a.
Check
for
defective resistor, R662 & R663.
8.
TEST EQUIPMENT REQUIRED FOR SERVICING
Table 1 lists the test equipment required
for
servicing the Model 4430 Receiver.
Item
Manufacturer
and
Model No.
AM
Signal Generator
Test Loop
FM
Signal Generator
Less
than 0.3% distortion
Stereo Modulator
Less
than
0.3%
distortion
Audio
Oscillator
Weston
Model CV0-100P,
less
than 0.02% residual distortion
is
required.
Oscilloscope High sensitivity
with
DC
hori-
zontal
and
vertical amplifiers.
VTVM
With AC,
DC,
RF
range
Circuit Tester
AC Wattmeter Simpson, Model 390
AC Ammeter Commercial Grade (1-10A)
Line Voltmeter Commercial Grade
(0-150V AC)
Variable Autotransformer Powerstat, Model 116B
(0-140V AC, 10 amps)
Shorting Plug
Use
phono plug
with
600
ohm
across
center pin
and
shell.
Output
Load Commercial Grade
(8 ohms,± 1 % 1
OOW)
Output
Load Commercial Grade
(4 ohms,
± 1 % 1
OOW)
Use
Signal source
for
AM
align-
ment.
Used
with
AM
Signal
gen-
erator.
Signal source
for
FM align-
ment.
Stereo separation alignment
and
trouble shooting.
Sinewave
and
squarewave
sig-
nal
source.
Waveform analysis
and
trouble
shooting
and
ASO alignment.
Voltage measurements.
Trouble shooting.
Monitors primary power
to
Amplifier.
Monitors amplifier
output
un-
der short
circuit
condition.
Monitors potential
of
primary
power
to
amplifier.
Adjusts level
of
primary
power
to
amplifier.
Shorts amplifier
input
to
eliminate noise pickup.
Provides 8-ohm load
for
amplifier
output
termination.
Provides 4-ohm load
for
amplifier
output
termination.
Table
1
Test
Equipment
Required
for
Servicing
9.
AM
ALIGNMENT
PROCEDURE
9.1
AM
IF
Alignment
1. Connect a
sweep
generator
to
the J
151
and
an
alignment
scope
to
the J 162.
2.
Rotate
each
core
of
IF transformer L 153
and
L 154
for
maximum height
and
flat
top
sym-
metrical
response.
•
-
j
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