transistor H151 through a capacitor
the conversion
out
board P150.
AM
The
and
input
signals induced in a ferrite bar antenna
of
noises,
circuit
thus giving good SIN performance. The tuned circuits inserted in both
of
the
RF
amplifier
formance. Thus amplified and selected AM signals
transistor H152 through a coupling capacitor C156. While
to
the emitter
mixed at the base-emitter junction
resulting IF signal
two
tuned circuits.
The
transistor
to
detect audible signal through the detector transformer L154. The detected audio signal
output
of
next
of
H 152 through a capacitor C157,
and
is
of
stage
applied
L153
to
the
is
led
to
H154. The
first
the transistor H 153 which in
fully
filtered and amplified and the final audio
applied
The
to
the
DC
component
TAPE
OUT
jacks and the function switch.
of
the detected IF signal
and
C151
and amplified
assure
ferrite bar antenna
are
applied
to
the level required
very high
are
image
then applied
are
mounted on a printed
to
the
base
of
for
and
spurious rejection per-
to
the
base
RF
overcoming
of
the local oscillator voltage
both
AM
signals
and
oscillating voltage
converted into 455KHz intermediate frequency. The
IF transformer L 153 consisting
amplified IF
output
output
is
obtained
is
used
is
then applied
from
as
a AGC voltage
of
one ceramic
turn
apply its
the collector
output
to
the diode H157
of
to
control emitter
amplifier
converter
is
injected
are
filter
and
to
the
H 155
and
is
Page 4
-----------·~
current
R179 and R151. A
capacitor C167 and rectified
M010.
2.1 Suggestions
slowly and observe the
meter
preceding final IF transformer L154. Next connect a oscilloscope
J 157 and check
does
the oscillator tuning capacitor
measuring oscillating voltage
local oscillator voltage
VTVM
3. FM
IF
duced by a FM antenna
switch and a balun coil. These signals
applies its
The
the
FET
next
Three pieces
of
capture ratio and good
is
transistor limiter. The detected audio
ed
OUADRADIAL
through R483.
of
H 153 which in
for
AM
for
Check
gives
not
and compare
The FM Tuner section
Amplifier
FET
same
Mixer, the injection voltage
IF
amplifier
The IF amplifier
symmetrical diode limiters
A part
fed back
The
output
broken
a deflection at
for
audio signals
deflect, check the local oscillator circuit. Normal oscillating voltage
the
TUNER
and Detector, Muting Control and MPX Stereo Decoding Circuit. FM signals
output
Mixer convert its
time. The H 103
of
to
IF
signal sufficiently amplified through every
is
to
unit
of
dual elements ceramic filters
FM
Front
the gate
led
to;
jack on the rear panel through resistor R484, (c) MPX stereo decoding
turn
part
Tuner Trouble Shooting
AM
bar antenna, next
AM
signal strength meter whether
is
normal, check all voltage distribution in the
measured values
of
the next
through a coaxial cable.
unit
consists
AM
suppression.
End
of
FET
(a)
noise amplifier
control the bias current
of
IF signal
to
obtain
several
input
is
output
frequencies received, no failure may exist in the
with
is
about 2
use a RF
Model 4430
are
led
FET
Mixer H102 through the double tuned high selective circuits.
signal into 10.7MHz intermediate frequency and amplifies
a local oscillator and its
is
of
are
also employed
is
RF
amplifier
output
DC
current
try
the tuning meter deflected.
or
3 volts, varying
VTVM,
with
those given in the schematic diagram.
is
divided
to
FM antenna coil L101 through
are
then applied
about 700mV. The 10.7MHz
five
stages
are
applied
to
to
output
H471
of
the RF amplifier through the resistor
is
also applied
for
energizing the
to
tune station by rotating fly-wheel tuning
it
deflects
with
no
circuit
of
IF amplifier and one
also
for
the AGC amplifier H201 and rectified its
decrease the gain
is
led
through resistor R471 and capacitor C471, (b)
tester
into
four
to
output
used
to
the best
stage
of
to
the
to
tuning capacitor position. When
gives
functional blocks: FM
the
FET
is
injected
obtain high selectivity,
limiting
IF amplifier
buffer
the diode H158 through a
AM
signal strength meter
knob
or
not. If
to
the pin terminal J162
If
the signal strength meter
correct indication.
AM
RF
front
characteristics, improved
with
increased signal strength.
amplifier H208 and its buffer-
the signal strength
stages
at
the
circuits
amplifier
into
end
stage
is
finally
by
ATTENUATOR
which
the source
output
of
AGC amplifier.
applied
at
hot
using a
Front
is
led
four
least
end
If
the
DC
End,
in-
in
turn
it
of
the
to
the
stages
output
to
the
circuit
or
of
at
2
3.1
Audio
The muting
the Model
the second
ponent
from
free
The
is
applied
(muting threshold level).
emitter-collector resistance increasing and the collector voltage
collector voltage increases the gate bias voltage and turns on the switching
the source-drain resistance
to
flow
Muting
4430.
to
of
the detector output. These inputs
noise and transients.
first
input
to
the
to
the center
and Stereo Mode Auto-Selecting
circuit
Three inputs control the muting function. The
the noise
base
consisting
condition
of
DC voltage obtained by rectifying a part
of
H306
When
to
of
38KHz switching transformer through the source-drain path.
of
all solid-state electrical switching
at the detector and the
and
turns on it,
the H306
near zero ohm and allowing the audio signal applied
Circuit
first
third
are
properly matrixed and gated
of
IF
if
the
IF
output
is
turned on the H307
is
greater than predetermined level
rises
has
is
related
is
derived
output
is
turned
about 9V. The increased
been incorporated in
to
singal strength,
from
the
DC
com-
to
provide muting
signal
from
the H206
off,
allowing the
FET
H308, decreasing
to
the source
Page 5
When
can
decreasing the collector voltage and turning
the F ET. This
ing operation the second and the
misoperation due
audio signals
sistor H471
to
the
tuned in,
resistance
the H308
through
is
also turned
H302, resulting
noises
curve is applied
R486). The
positive values
frequency
source potential
... H307
amplified and
predetermined level,
H480
just described above.
noisy side-audio signals
automatically and open
transistor H480 and H481
the
input
signal
not
turn
on the H306, thus the H306
is
the fundamental principle
The second
noise components in the audio signals.
When there are excessive
the
The transistor H303 connected in
is
also avoided.
third
The
When the
turn
Thus when the tuning
With the station correctly tuned in, the
input
to
are
separated
and
its
output
the
rectified
to
zero. This
is
turned
FET's source-drain path.
off
(when the transistor H472
in
turning
input
to
DC
output
or
vice
from
the correct tuning frequency.
DC
output
of
turn
on, ... H308
no
stereo beacon
on and
the
is
lower than predetermined level, the
third
inputs
is
used
to
protect the muting operation and MPX stereo beacon lamps
undesirable
by
is
DC
output
means
off
and any audio signals having
off
is
obtained
the gate
is
versa
is
H478
makes
the
decreased
H306 in turned
is
are
produced, both muting and 19KHz switching transistors
the
circuits.
are
noises.
a small capacitor
rectified
noises
of
zero
increased
turn
shifted-or-deviated
not
by
the
in the audio signals
turns on the transistor H472, decreasing the emitter-collector
the collector
series
the
stereo beacon lamps. Thus misoperation due
from
the
FM
H478 through a resistor R273 and
with
a station correctly tuned in,
when the tuning
to
a greater level than
the transistor H481
off,
... H303
is
turned on.).
source potential turns
off.
turned on, giving no effect on the transistor H306.
DC
output
keeps
its
turn-off
off
H308. Thus no audio signals
of
the muting operation
are
necessary.
The high frequency noises included in the detected
C471
and amplified by the noise amplifier tran-
two
diodes. The rectified
such
of
H307
excessive
with
the 19KHz
or
H307
are
discriminator circuit. The
point
turn
turn
off
When
the
The subsequent
to
the certain frequencies in which undesirable
bias
current
stage
and this makes H307
as
obtained
is
short-circuited
high frequency
pilot
signal amplifier transistor H302
turned on.) and no current flows
but
is
deviated toward either plus
that
of
predetermined, the increased
on, and this makes the H306
(this
means
DC
output
off
the H479 which in
changes
of
the FET H478
obtained
can
but
for
more elaborate mut-
DC
output
with
to
the ground, therefore
DC
dividing
will
vary
rio 19KHz
is
increased
are
exactly the
is
adjusted
is
a station incorrectly
noises
to
output
network (R485 &
from
pilot
to
turn
is
small and
turn
on,
pass
through
from
proportional
can
not
go
in
the
undesirable
so
called
negative
the negative
makes
same
are
so
"S"
or
minus
turn
off,
signal
the
as
that
operated
that
both
to
is
3.2 MPX Stereo Decoding
The buffered and non-equalized audio signals
serve
as
a tuned amplifier
the audio signals. The amplified 19KHz
and
further
described in the preceding chapter. The final 19KHz
circuit
The H304
consisting
transformer
to
the crosstalk cancelling amplifier which utilizes complementary configuration
PNP
transistors through de-emphasis network consisting
is a low-pass
L305
sirable residual switching signals. Transistors H313 and H314
outputs
amplified
consisting
is
the
of
four
1I2
are
led
to
of
the
38KHz
diodes. While the composite signals
L302. The right and
filter
the function switch.
Circuit
for
the
pilot
signal in the composite signals and
pilot
if
switching transistor H303
H315 and H316
tuned amplifier
networks having very sharp
to
obtain synchronized
and
left
stereo signals decoded
are
applied
signal
is
led
is
turned on
supplies its
are
of
cut
off
to
the
first
as a buffer
to
the second 19KHz amplifier H302
by
the controlling
pilot
signal
output
applied
C315
characteristics and eliminates unde-
is
rectified
38KHz
and
are
amplifier driving signal.
to
the switching
to
the center tap
by
the switching
R335, and C316 and R336,
buffer
amplifier H301 which
amplifier
DC
by
the doubler
matrix
of
switching
circuit
with
amplifiers and their
for
signal
as
circuit
are
led
NPN and
3
Page 6
...
-. ..
-
a.--•~
3.3 Suggestion
3.3.1 Symptom: No
First turn on the power switch
knob slowly
several
failure.
VTVM.
depending on the tuning capacitor position.
all voltage distribution in the
shown
check audio circuits, using high sensitive oscilloscope.
3.3.2 Symptom: No Stereo Separation
output
stereo beacon
switching signal, using
4.
amplified
AUX1, AUX2, jacks
the TAPE OUT jacks
The TAPE MON switch selects the
jacks
mode switch
volume control. The
through the balance control section
frequencies received, the tuner circuits preceding the discriminator circuit may
When
The normal local oscillator voltage
in
First check the
modulated by a stereo modulator
PHONO
Signals from the PHONO jacks
and
Applied
and
for
Trouble Shooting
FM
Reception
and
observe the
no reading
the circuit diagram.
"MONO"
is
turned on
AND
PRE-AMPLIFIER
RIAA
are
to
the other section
the selected
and
its associated circuit and applied
is
or
an
oscilloscope.
equalized phono
applied
and
mode switch.
signals
bass
and
of
FM
Tuner
and
try
to
tune
FM
signal
strength meter.
obtained
FM
switch
not.
to
go
in
the meter, check
is
one
If
the local oscillator voltage
Front
End
and
IF amplifier
When
treble controlled
signal
is
in normal
If
are
applied
signals
the selector switch which, in turn,
of
the TAPE MON switch
signals
to
the pre-amplifier.
and
strength meter deflects
out
to
the
rear
not turned on, check
to
the phono amplifier mounted on P700. The
and
signals
from the mode switch or those from the TAPE IN
the hi-filter before they
FM
stations. Rotate the fly-wheel tuning
If
the
signal
strength meter deflect at
FM
local oscillator circuit, using a
or
two
volts (rms) at the tuning capacitor,
is
normal,
unit
and
compare them
but
no sound
position. Connect a
FM
ANTENNA
for
19KHz
from the tuner section
are
signals
Signals
to
the tone control amplifier through the
signals
are
from the tone control amplifier
reach
FM
RF
terminals,
pilot
leads
the selected signals
from the TAPE IN jacks.
then mode
the main amplifier.
is
signal
and
signal
and
processed
have
no
RF
next
check
with
those
obtained,
generator
check the
and
38KHz
the TAPE,
to
by the
pass
~
·
4.1 Mode Switch
Mode switch S005
DECODER.
In the MONO position, all
In the 2
left-front (LF)
(LF
+LR)
In the DISCRETE position,
channel.
In the
phonic
directly
from the 2-channel
RR
channel
When
CH
position,
and
left-rear (LR)
are
delivered
VARI-MATRIX
signals
to
through the vari-matrix circuit; the input right
the LF
signal
Dimension Control Setting
the dimension control
and
input
components
Minimum
Center
Maximum (FCW)
has
positions
input
each
pair
to
the pairs
position, 2-channel stereo input
RF
channels, while the
signals
are
(FCCW)
of
MONO, 2
signals
of
are
of
each
under the control
controlled by the dimension control
is
set
are
mixed together
input
signals
mixed together. The resultant
RF
and
RR,
channel
to
signal
signals
LR
LF
LF
j_
the minimum position the LR
LF-
CH,
DISCRETE,
and
right-front (RF)
and
LF
and
LR channels, respectively.
is
separately routed
signals
and
to
the LR
of
the dimension control. The LR
Output
+RF
RF
and
VARI-MATRIX,
delivered
are
left
RR
RR
RF+
RF
RF-
to
and
right-rear (RR),
signals
to
converted
channel signals
channels
as
shown below.
Output
LF
LF
and
RR
the corresponding
all
four
(RF +
are
channel
into
and
SQ
channels.
and
RR)
and
quadra-
are
fed
synthesized
and
signals
4
Page 7
become monophonic,
providing vanished sound
SQ
In the _
decoded
Model SQA-1,
4.2 Balance Control
Signals
signals
setting the FRONT-REAR balancer
"L"
Model
"REMOTE"
the Model
4430
RC-4
further
5.
stability.
power
operating
and
This
power
are
side,
The balance control
RC-4
or
Model
is
determined by the volume control on the Model 4430.
Balance controlled signals
power amplification.
POWER
Differential amplifier consists
The transistor H605 drives the inverter transistors H611
stage
Excessive current
the resultant variation
decreases
output
DECODER position, signal sources encoded by the
into
4-channel signals. Required
into
from
controlled by three balancers: FRONT L-R, REAR L-R,
for
example,
Remote Control Box operative when
position the balancers
RC-4.
RC-4.
AMPLIFIER
consisting
as
a power transistor protection circuit.
the
stage
to
the center
image
the Model 4430.
the tone
The volume level
base
(H001 and H002)
wntrol
only
the
circuit
However, the maximum volume level available by adjustment
of
H001
flow
in the power
is
applied
biasing current
are
stereophonic, and
positioning.
for
this operation
amplifiers
to
front
left
is
provided
on
can
are
led
of
the transistors H601 and H603
and
to
is
are
fed
the
"FRONT"
channel
the Model 4430 become ineffective since signals
be
through the hi
H002. Transistors H607
output
the transistors H607
for
H611
restricted
is
with
the remote control switch which makes the
adjusted by the volume control either on the Model
stage
and
within a safe
to
the maximum
is
incorporation
into
the balance control circuit, in which the
side
and
the
FRONT
drived.
set
to
the
"RE
filter
to
the main amplifier section
and
H613 which, in turn, drive the
and
is
detected by the resistors R642 and R644
and
H609
H613. In this way the current
predetermined value.
are
out
of
CBS
SQ
system
of
the
SQ
and
FRONT-REAR. By
L-R balancer
MOTE"
to
provide satisfactory
H609
and
position. In the
of
are
current
make them turned on.
phase,
are
Adaptor,
are
the Model
flow
thus
ideally
to
the
led
to
for
D.C.
limiter
in the
6.
POWER SUPPLY
The power supply
matic voltage regulator provides +35V
and
H803 which operates
H808, H809 and H810 which operates
7.
AUDIO
1.
Excessive line consumption
2.
No line consumption
3.
Excessive hum
4.
Parastic oscillation
TROUBLE
UNIT
and
noise level
unit
consisting
as
the voltage regulator provides +14V
ANALYSIS
or
zero
bias
of
transistors H805
DC
to
all
of
the audio amplifiers except power amplifiers,
as
the speaker protector
a.
Check
H854.
b.
Check
HOOS.
c.
Check L003
a.
Check line cord,
H626
b.
Check
or open L003.
a.
Check
C605
b.
Check
a.
Check
C619, C620,
and
H806, which operates
DC
to
the tuner section,
to
relay circuit.
for
shorted rectifiers H851 through
for
shorted transistors H001 through
for
short.
fuse,
shorted H581 & H582,
& H627.
for
open rectifiers H851 through H854,
filter
capacitors C006 through C009,
as
& C606.
for
shorted transistor H805.
for
defective capacitors, C607, C608,
C621
and
C622.
an
auto-
and
5
Page 8
•
-----------·~
a.
5.
Improper clipping
8.
TEST EQUIPMENT REQUIRED FOR SERVICING
Table 1 lists the test equipment required
Item
AM
Signal Generator
Test Loop
FM
Signal Generator
Stereo Modulator
Audio
Oscilloscope High sensitivity
VTVM
Oscillator
Manufacturer
Less
than 0.3% distortion
Less
than
Weston
than 0.02% residual distortion
is
required.
zontal
With AC,
and
for
and
0.3%
distortion
Model CV0-100P,
vertical amplifiers.
DC,
RF
Check
servicing the Model 4430 Receiver.
Model No.
with
DC
range
less
hori-
for
defective resistor, R662 & R663.
Use
Signal source
ment.
Used
erator.
Signal source
ment.
Stereo separation alignment
and
Sinewave
nal
Waveform analysis
shooting
Voltage measurements.
with
trouble shooting.
source.
for
AM
AM
Signal
for
and
squarewave
and
and
ASO alignment.
align-
FM align-
trouble
-
j
gen-
sig-
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
Output
(8 ohms,± 1 % 1
Output
(4 ohms,
Load Commercial Grade
Load Commercial Grade
± 1 % 1
OOW)
OOW)
Use
phono plug
across
ohm
shell.
Table 1 Test
center pin
Equipment
with
600
and
Required
Trouble shooting.
Monitors primary power
Amplifier.
Monitors amplifier
der short
Monitors potential
power
Adjusts level
power
Shorts amplifier
eliminate noise pickup.
Provides 8-ohm load
amplifier
Provides 4-ohm load
amplifier
for
Servicing
circuit
to
amplifier.
to
amplifier.
output
output
of
output
condition.
of
primary
primary
input
termination.
termination.
to
for
for
to
un-
6
9.
AM
ALIGNMENT
9.1
AM
IF
Alignment
1. Connect a
2.
Rotate
metrical
each
response.
sweep
core
PROCEDURE
generator
of
to
the J
IF transformer L 153
151
and
an
alignment
and
L 154
scope
to
the J 162.
for
maximum height
and
flat
top
sym-
Page 9
9.2
AM
Frequency
1.
Set AM signal generator
tuning pointer at the
2.
Set the signal generator
and adjust the oscillator
output.
3.
Repeat the step 1
4.
Set the generator
core
of
AM ferrite rod antenna
5.
Set the generator
trimming
6.
Repeat the step 4
Note: During tracking alignment reduce the signal generator
action.
capacitors
Range
and Tracking Alignment
low
end.)
to
and 2 until
to
600KHz
to
1400KHz
of
antenna
and 5 until
to
525KHz.
and
adjust the oscillator coil L 152
1650KHz.
trimmer
no further adjustment
and
tune the receiver
and
and
and
no further adjustment
Turn the tuning capacitor
Place
on
the oscillator tuning capacitor
RF
coil L
tune the receiver
RF
tuned
the tuning pointer in the high frequency
is
necessary.
to
the
151
for
maximum output.
to
circuit
for
is
necessary.
fully
for
maximum audio output.
for
same
frequency
the
same
frequency
maximum output.
output
as
necessary
closed (place the
end
maximum audio
and
adjust a slug
and
acijust both
to
avoid AGC
10. FM
1.
2.
3.
4.
5.
6.
7.
10.1 Stereo Separation Alignment
1.
2.
3.
ALIGNMENT
Connect a FM signal generator
audio distortion analyzer
Set the
frequency
obtain maximum audio output.
Set the FM
and place the tuning pointer at the high frequency
C106
Repeat the step 2
Set the FM
generator
Adjustthe
audio distortion.
Setthe
capacitor C102, C104
Adjust the secondary core(upper)of discriminator transformer L201
meter pointer indicates its center at no signal applied. Set the FM
its
tuning meter pointer indicates its center. Adjust the primary core (lower)
minimum distortion.
Set the
the center tuning meter pointer indicates its center.
Modulate the FM
course a
then, modulate the signal generator
signal and
Adjust the
FM
SG
end
SG
for
maximum output.
SG
output
antenna coil L 101,
FM
SG
output
level
FM
SG
pilot
again
trimming
PROCEDURE
to
the FM
to
the TAPE OUTPUT jacks on the rear panel.
to
87.5MHz
by rotating the tuning knob
to
108.5MHz
and 3 until
to
90MHz
until
to
106MHz
to 1 KµV
to
provide 1 Kµ V at 98M
SG
signal must
adjust the core
resistor R365
and
provide about 3
and
provide about 3
no further adjustment
and
tune the receiver
the audio
and
and
C105
with
be
output
RF
coil
L102andL103
tune the receiver
for
minimum distortion.
and tune the receiver
stereo composite signal consisting
included). Adjust the core
with
of
L301
for
for
maximum
ANTENNA
to
and
level
decreases
to
Hz.
Tune the receiver
a stereo composite signal consisting
maximum audio output.
and
terminals and a oscilloscope
5µV.
adjust the core
to
to
the
to
Place
the tuning pointer at the
of
oscillator coil L 104
5µV output. Rotate the tuning knob
end
and
adjust the
is
necessary.
the
same
frequency.
with
the decreasing generator output.
and
IF transformer L 105
same
frequency.
so
SG
to
the
same
frequency
to
the
same
of
only
of
L301
for
maximum audio
same
separation in both channels.
and
trimming
Adjustthe
that
the center tuning
98MHz and increase
so
frequency
subchannel signal
of
capacitor
Decrease
for
minimum
trimming
that
the center
of
L201
output.
only
L channel
signal
so
an
low
to
for
that
(of
10.2 Muting
1.
Connect a
0.
75V
DC
2.
Set the FM
correctly.
Circuit
VTVM
at no signal.
SG
to
Alignment
across
provide 1 KµV at 98MHz and tune the receiver
the resistor R487 and adjust the resistor R487
to
until
the
the meter
same
frequency
reads
7
Page 10
-----
----
.-.•-:.-.
3. Turn on MUTING pushswitch.
and
note both plus
are
muted out. Adjust the R487
side
response.
11.
AUDIO ADJUSTMENT
1.
Connect a
VTVM
and adjust the R629
2.
Connect a
VTVM
and adjust the R614
12.
AUTOMATIC VOLTAGE REGULATOR ADJUSTMENT
Connect a
under no
reads
reads
signal
VTVM
10mV
VTVM
VTVM
condition.
OV
DC.
and
minus shifted frequencies at which undesirable audio