Marantz 6300 - 2. CIRCUIT OPERATION; 2-1. AUTO MODE; 2-2. MANUAL MODE

ete!
nee neem Eni -z.
2. CIRCUIT OPERATION
2-1. AUTO MODE
1. CUE-DOWN
After
placing
the
tone
arm
over
the
record
and
pressing
the
CUE-DOWN
button
the
following
sequence
of
operations
will
occur.
The
CUE-DOWN
button
mechanically
unlatches
solenoid
L002
and
places
switches
S003,
S005, S006,
S009
and
SO10
in
their
released
or
unlatched
position.
The
unlatching
of
L002
causes
the
push
plate,
Ref.
Desig.
0630,
which
is
secured
to
L002
to
move
in
a
downward
direction.
This
in
turn
allows
the
hydraulically
dampened
arm
lifter
to
lower,
thereby
lowering
the
tone
arm
onto
the
record.
2. CUE-UP
To
lift
the
tone
arm
and
stop
the
turntable
before
the
end
of
the
record,
press
the
CUE-UP
button
(S007).
When
the
CUE-UP
button
is
pressed,
an
increased
voltage
is
applied
to
the
gate
of
thyristor
H805
causing
it
to
conduct
and
energize
solenoid
LOO2.
(continued
under
SHUT-OFF
SEQUENCE
OF
OPERATIONS.)
3. AUTOMATIC SHUT-OFF
At
the
end
of
the
record
as
the
tone
arm
nears
the
center
spindle,
the
light
shield,
Ref.
Desig.
1329
which
is
attached
to
the
underside
of
the
tone
arm,
has
traveled
to
a
point
where
it
blocks
the
light
emitted
by
the
light
emitting
diode
LN25
from
reaching
phototransistor
PH101.
When
this
occurs,
the
collector
voltage
of
PH101
increases
which
inturn
causes
the
gate
voltage
of
thyristor
H805
to
increase
thereby
enabling
H805
to
conduct
and
energize
L002.
(continued
under
SHUT-OFF
SEQUENCE
OF
OPERA-
TIONS.)
4. SHUT-OFF SEQUENCE OF OPERATIONS
Energizing
LOO2
causes
it
to
latch
and
places
switches
S003,
S005,
S006,
S009
and
S010
in
their
latched
position.
When
latched,
switch
SOO6
opens
the
collector
circuit
of
H805
causing
LOO2
to
de-energize
(while
remaining
in
a
mechanically latched position).
The
latching
action
of
LOO2
causes
the
previously
referred
to
push
plate,
Ref.
Desig.
0630,
to
move
in
an
upward
direction,
raising
the
arm
lifter
which
raises
the
tone
arm
from
the
record.
The
same
latching
operation
removes
power
to
the
motor
via
S005,
removes
power
to
the
primary
of
the
AC
transformer
via
S003
and
mutes
the
audio
output
via
S009
and
S010.
2-2. MANUAL MODE
Placing the MANUAL/AUTO switch (S002 and S004) in
the MANUAL position has the following effect on circuit
ope ration:
1. Renders PH101 ineffective by adding R805 to the
collector circuit thereby reducing collector current and
voltage to a level insufficient to trigger H805.
2. Prevents the CUE button from having any effect on
voltage supplied to the motor or transformer.
2-3. PHOTO UNIT H002
The photo unit HO02 consists of LN25, a red light emitting
diode; and PH101, an NPN Epitaxial Darlington photo-
transistor. Whenever power is applied to the turntable,
LN25 will conduct a current of approximately 17 mA
causing it to emit a red light.
PH101 when exposed to this light will conduct. In the
AUTO mode the collector load resistance of PH101 is
comprised of only R809 (R805 is bridged by S004) thus
enabling approximately 1.2 mA to flow through the circuit
of PH101. The resultant collector voltage of PH101 is
coupled to the gate of thyristor H805, but the low level
voltage is insufficient to trigger H805 conduction.
This condition remains until at a preset position of the tone
arm travel, the light of LN25 is prevented from reaching
PH101. When this occurs the conduction of PH101
decreases, collector voltage of PH101 increases thereby
increasing the gate voltage of H805 and triggering H805
conduction.