Marantz PROFESSIONAL Series - Page 7

and
Q203
and
applied,
together
with
the
com-
parator
output,
to
the
OR
gate.
The
overload
signal
from
the
OR
gate
then
triggers
a
one
shot
multivibrator,
Q207-0209.
A
triac
CR207
inter-
faces
the
one
shot
to
the
AC
supply
that
powers
an
incandescent
“PEAK”
indicator
bulb.
The
GAIN —
CONTROL
POWER SWITCH
oa 0 el
AC LINE
FUSE
CR301
ZENER-
STABILIZED
POWER SUPPLY
Q301, 0302
UNITY GAIN
BUFFER AMPLIFIER
CR302
ZENER-
STABILIZED
POWER SUPPLY
one shot turns on instantaneously and is designed
to hold its output in the “on” state for several
milliseconds, thus allowing the bulb to come up
to full brilliance, so that even the shortest peak
transients in musical programs that cause overload
(clipping) will be observed.
K1
SOFT START
CIRCUIT
— 0304, 0306
DIFFERENTIAL
INPUT
+ AMPLIFIER
Q305
CONSTANT
CURRENT
SOURCE
Q303
TIME DELAY
CIRCUIT
FAN SPEED
CONTROL
THERMOSTAT
NEGATIVE
FEEDBACK
DIFFERENTIAL
309
POSITIVE
“DRIVE
CURRENT SOURCE
a4o1
BASE-EMITTER
MULTIPLIER
BIAS
REGULATOR
Q310
NEGATIVE
DRIVE
CURRENT SOURCE
Q313
POSITIVE
PRE-DRIVER
Q311 q
PROTECTION
TRANSISTOR. i
0312 ql
PROTECTION
TRANSISTOR
Q314
NEGATIVE
PRE-DRIVER
Q402
POSITIVE
SLAVE
DRIVER
Q403
POSITIVE
MASTER
DRIVER
NEGATIVE R360, R362
PROTECTION
LOGIC
Q404
NEGATIVE
MASTER
DRIVER
0405
NEGATIVE
SLAVE
DRIVER
POSITIVE R359, R361
PROTECTION
LOGIC SENSORS
Q406, 0410
POSITIVE
PARALLELED
PAIR
Q407, 0411
POSITIVE
PARALLELED
PAIR
CURRENT
CURRENT
SENSORS
Q408, 0412
NEGATIVE
PARALLELED
PAIR
Q409, 0413
NEGATIVE
PARALLELED
PAIR
O +Vs
VARIABLE
jOWER
UPPLY
REFERENCE
Q205
COMPARATOR
THERMAL
CJT-OUT
}
|sto1a
MER RANGE
{WITCH
A: SEMBLY
O-Vs ;
CR207
TRIAC
PEAK
LIGHT
Figure 1. Functional Block Diagram
7