Marantz TT-6000 - Switch Circuit Description

10
SWITCH CIRCUIT DESCRIPTION
START SWITCH FUNCTION
Pushing
the
start
button
turns
the
main
motor
drive
on
and
the
turntable
platter
starts
rotating.
After
a
few
seconds
of
rotation
the
turntable
locks
at
the
correct
speed.
Also,
this
circuit
temporarily
engages
the
rotary
solenoid
and
starts
the
tone-arm
motor.
The
tone-arm
cam
advances
its
rotation
and
engages
the
gear
switch
which
then
com-
pletes
the
rotary
solenoid
circuit.
With
the
tone-arm
motor
in
operation
the
tone
arm
will
advance
depending
on
the
travel
of
the
rotary
cam.
When
the
cam
completes
its
cycle
the
gear
switch
is
then
released
which
inverts
the
Flip-Flop
circuit
that
completes
the
rotary
solenoid
Circuit
and
stops
the
tone-arm
motor.
The
main
motor
still
remains
on.
REJECT SWITCH FUNCTION
When the reject button is depressed during operation, the
tone-arm
motor
is
turned
on
and
locks
the
gear
switch
due
to
cam
advancement.
The
tone-arm
returns
to
its
rest,
which
closes
the
rest
micro-switch,
inverting
the
Flip-Flop
Circuit,
and
stops
circuit
operation.
AUTOMATIC RETURN FUNCTION
The
voltage
potential
between
Pins
2
and
3
of
Opera-
tional
Amp.
UPC741C
determines
the
potential
(Hi
or
Lo
condition)
on
pin
6
of
this
amplifier
circuit.
The
reference
voltage
is
Pin
2
and
when
Pin
3
voltage
potential
exceeds
the
reference
voltage,
Pin
6
goes
to
high
level
condition.
The
speed
of
the
feed
arm
entering
the
LED
and
photo
transistor circuit determines Pin 3 voltage increases.
Adjusting
VR1
and
VR2
determines
the
correct
speed
of
the
tonearm
travel.
Normal
speed
is
1mm
pitch
but
when
the
record
program
is
over,
the
disc
spiral
moves
the
tone-
arm
pitch
speed
at.
3mm
and
increases
the
potential
at
Op.
Amp
Pin
3.
201
PHOTO-CELL
CIRCUIT
The correct voltage alignment is as follows:
T.P.
9
and
10
(collector-emitter)
Photo
Xstor
adjust VR1 for 0.2VDC
T.P. 9 and 11 (OP. amp. REF) Pin 2
adjust VR2 for 0.65VDC
The
output
Pin
6
is
differentiated
and
turns
the
Flip-Flop
circuit
on
which
starts
the
tonearm
motor
returning
the
arm
to
its
rest
and
closing
the
rest
switch,
stopping
circuit
operation.
REPEAT SWITCH FUNCTION
Pressing
the
repeat
switch
operates
an
AND
circuit
which
completes
the
rotary
solenoid
circuit
thus
starting
the
complete
circuit
cycle
over
until
the
repeat
switch
is
disengaged.
MANUAL OPERATION
When the tone arm is removed from the rest, the rest
switch is closed starting the turntable motor.
CUEING FUNCTION
CUE UP—
Momentarily depressing the cue switch by passes the gear
switch and starts the tone arm motor as well as turning the
main platter motor on. The tone-arm cam advances to the
lead-in position, this will stop the tone-arm motor because
the cueing switch is in the open position. The main motor
still remains on so the platter is rotating.
CUE DOWN—
Depressing the cueing button now reverses the tone-arm
motor rotation and returns the tone-arm cam until the
gear switch is returned to the off position.
NOTE:
In
the
cue-up
mode
of
operation,
start
and
reject
func-
tions
cannot
be
performed
due
to
incomplete
tone-arm
cam cycle. .
1C-7
UPC 741C
7 P ™
i Cc
4
AUTOMATIC
RETURN
CIRCUIT
SCHEMATIC
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