become monophonic,
to
the center
are
stereophonic, and
to
the maximum
are
out
of
phase,
thus
providing vanished sound
image
positioning.
In the _
SQ
DECODER position, signal sources encoded by the
CBS
SQ
system
are
ideally
decoded
into
4-channel signals. Required
for
this operation
is
incorporation
of
the
SQ
Adaptor,
Model SQA-1,
into
the Model 4430.
4.2 Balance Control
Signals
from
the tone
wntrol
amplifiers
are
fed
into
the balance control circuit, in which the
signals
are
controlled by three balancers: FRONT L-R, REAR L-R,
and
FRONT-REAR. By
setting the FRONT-REAR balancer
to
the
"FRONT"
side
and
the
FRONT
L-R balancer
to
the
"L"
side,
for
example,
only
the
front
left
channel
is
drived.
The balance control
circuit
is
provided
with
the remote control switch which makes the
Model
RC-4
Remote Control Box operative when
set
to
the
"RE
MOTE"
position. In the
"REMOTE"
position the balancers
on
the Model 4430 become ineffective since signals
are
led
to
the Model
RC-4.
The volume level
can
be
adjusted by the volume control either on the Model
4430
or
Model
RC-4.
However, the maximum volume level available by adjustment
of
the Model
RC-4
is
determined by the volume control on the Model 4430.
Balance controlled signals
are
led
through the hi
filter
to
the main amplifier section
for
further
power amplification.
5.
POWER
AMPLIFIER
Differential amplifier consists
of
the transistors H601 and H603
to
provide satisfactory
D.C.
stability.
The transistor H605 drives the inverter transistors H611
and
H613 which, in turn, drive the
power
stage
consisting
of
H001
and
H002. Transistors H607
and
H609
are
current
limiter
operating
as
a power transistor protection circuit.
Excessive current
flow
in the power
output
stage
is
detected by the resistors R642 and R644
and
the resultant variation
is
applied
to
the transistors H607
and
H609
and
make them turned on.
This
decreases
the
base
biasing current
for
H611
and
H613. In this way the current
flow
in the
power
output
stage
(H001 and H002)
is
restricted
within
a
safe
predetermined value.
6.
POWER SUPPLY
UNIT
The power supply
unit
consisting
of
transistors H805
and
H806, which operates
as
an
auto-
matic voltage regulator provides +35V
DC
to
all
of
the audio amplifiers except power amplifiers,
and
H803 which operates
as
the voltage regulator provides +14V
DC
to
the tuner section,
and
H808, H809 and H810 which operates
as
the speaker protector
to
relay circuit.
7.
AUDIO
TROUBLE
ANALYSIS
1.
Excessive line consumption
2.
No line consumption
or
zero
bias
3.
Excessive hum
and
noise level
4.
Parastic oscillation
a.
Check
for
shorted rectifiers H851 through
H854.
b.
Check
for
shorted transistors H001 through
HOOS.
c.
Check L003
for
short.
a.
Check line cord,
fuse,
shorted H581 & H582,
H626
& H627.
b.
Check
for
open rectifiers H851 through H854,
or open L003.
a.
Check
filter
capacitors C006 through C009,
C605
& C606.
b.
Check
for
shorted transistor H805.
a.
Check
for
defective capacitors, C607, C608,
C619, C620,
C621
and
C622.
5
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