Marantz SUPERSCOPE CRS-2104 User manual

SUPERSCOPE
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3c.
curswonre
BY BREmen Been me iiz.© CALIFORNIA 91311-U.S.A.

CRS-2104
TABLE OF CONTENTS
SPECIFICATIONS
1.
FEATURES
2. DISASSEMBLY
10.
2.1 Removing the Cassette Compartment Lid
2.2 Removing the Back Cover
2.3. Removing the Chassis
2.4 Removing the Mechanical Assembly
SERVICE GUIDE
3.1 Battery Voltage
3.2 Battery Polarity
3.3. Cleaning the Heads
3.4 Current Consumption
3.5 Voltage Conversion
. DIAL STRINGING
. MECHANICAL ADJUSTMENTS
5.1. Checking the Play Operation
5.2 Adjusting the Pause Timing
5.3 Adjusting the Fast Forward and
Rewind Torque
5.4 Adjusting the Pinch Roller Pressure
5.5 Adjusting the Play Torque
5.6 Adjusting the Flywheel Thrust
5.7 Positioning the Motor Pulley
5.8 Adjusting the Tape Speed
ELECTRICAL ADJUSTINGS AND
MEASUREMENTS
6.1 Adjusting the Playback Level
6.2 Adjusting the Head Azimuth
6.3 Adjusting the Bias Current
6.4 Measuring the Signal-to-Noise Ratio
(in Playback Mode)
6.5 Measuring the Playback Frequency
Response
6.6 Measuring the Combined Recording and
Playback Frequency Response
6.7. Measuring the Combined Recording and
Playback Level
6.8 Measuring the Combined Recording
and Playback Distortion
6.9 Measuring the Combined Recording
and Playback Signal-to-Noise Ratio
6.10 Measuring the Erasing Level
6.11 Calibrating the VU Meter
. ALIGNMENT PROCEDURES
7.1 FM Alignment Procedure
7.2 FM Stereo Separation Alignment Procedure
7.3. MW Alignment Procedure
7.4 LW Alignment Procedure
7.5 SW Alignment Procedure
DIAGRAMS
8.1 Level Diagrams
8.2. Block Diagram
8.3. Schematic Diagram
8.4 Circuit Board Diagram
. MAJOR COMPONENT LOCATIONS
9.1 Cabinet - Front View
9.2 Chassis - Top View
EXPLODED VIEWS AND PARTS LIST
10.1 {C01-99] Front Case
10.2 [(C02-99] Rear Lid and Upper Case
10.3 [M01-99] P.W. Boards and General Parts
10.4 [P01-99] Operation Levers and Buttons
10.5 [P02-99] Head Chassis
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22
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23
24
25
25
10.6 [P03-99] Flywheel
10.7 [P04-99] Parts Assembled on the Top
of the Chassis
10.8 [PO5-99] Parts Assembled on the Reverse
of the Chassis
10.9 [HO1-99] Packing Materials
10.10 Electrical Parts List
26
26
27
28
29

CRS-2104
SPECIFICATIONS
GENERAL:
DIMENSIONS (Wx Hx D). . .15-7/16 x 9-3/16 x 4-15/16 in.
(39.2 x 23.3 x 12.5 cm)
9 Ibs., 4 oz. (4.2 kg)
110/220 V AC, 50 Hz, 18 W
Six ‘‘D’”’ Size Batteries
External 9 V DC
WEIGHT (with batteries)
POWER REQUIREMENT ..
NUMBER OF SEMICONDUCTORS:
Integrated Circuits
Field Effect Transistors
Transistors
Light Emitting Diodes
Diodes
TERMINALS:
Microphone x 2
Plug Type: Mini
Input Sensitivity: 0.25 mV (—72 dB)
tmpedance: 4.5 kQ
Plug Type: Mini
Input Sensitivity: 55 mV (—25 dB)
Impedance: 60 kQ
Plug Type: DIN
Input Sensitivity: 20 mV
Impedance: 40 kQ2
Plug Type: DIN
Output Level: 0.5 V (-6 dBV)
Output Impedance: 2.5 kQ
Plug Type: Mini
Output Power: 2.2 W x 2 (42) DC
External FM Antennax1.... Input Impedance: 75 2
Stereo Headphone x 1 Plug Type: Phone
Impedance: 8 Q
External Input x 2
DIN Input
DIN Output
External Speaker x 2
AC Inlet x 1
DC9Vx1
Remote Control x 1
TAPE RECORDER SECTION:
Philips Type Cassette Tape
4-Track Stereo
AC Bias
AC Erase
110 Seconds (C-60)
. 125 Hz to 8 kHz (—5 dB)
ERASING SYSTEM
REW/FF TIME
FREQUENCY RESPONSE
SIGNAL-TO-NOISE RATIO
TAPE SPEED 1-7/8 ips (4.8 cm/sec) +3%
Less than 0.2% rms
TUNER SECTION:
CIRCUIT SYSTEM 4-Band FM/MW/SW/LW
Superheterodyne
FM: 88 to 108 MHz
MW: 525 to 1605 kHz
SW: 6 to 18 MHz
LW: 150 to 370 kHz
FM: 10.7 MHz
MW/SW/LW: 455 kHz
FM/SW: Telescopic Rod
MW/LW: Ferrite-rod
FM: 6 uV (30 dB S/N)
MW: 600 uV/m (20 dB S/N)
SW: 150 nV/m (20 dB S/N)
LW: 900 nV/m (20 dB S/N)
SIGNAL-TO-NOISE RATIO... FM: 45 dB (Input 1 mV}
MW/SW/LW: 40 dB (Input 5 mV/m)
FM STEREO SEPARATION 25 dB (Input 1 mV)
INTERMEDIATE FREQUENCY
ANTENNA

CRS-2104
1. FEATURES
(1) Full IC Circuits Construction
@ Audio full-line three-IC stages
Each audio channel consists of three !Cs: an equalizer
amplifier having ALC, a line amplifier, and power ampli-
fier. The power amplifier IC is made up of SEPP circuit
that assures 2.2 W output power per channel with 9 V
source. The audio full-line is illustrated below.
EQ
LINE
POWER
SPK
@ Quadrature-detection AM/FM and IF IC
The quadrature detection, which is the same as that of
usual hi-fi tuners, provides quality tone with little distor-
tion. The single hump tuning and S-curve alignment can
be accomplished by adjusting two points only, to which
5 or more points in the previous circuit are reduced.
@ Low-voltage, PLL multiplex FM stereo IC
The present PLL (phase-locked loop) multiplex IC can
be run by power voltage as low as 6 V for the first time
as the source voltage for the tuner is decreased to 6 V
through a ripple filter, while previous ICs requires 12-V
power source for good channel separation, for stable,
wide sound field. Alignment can be accomplished very
easily by adjusting two semifixed controls only as com-
pared with inductor adjustment in previous circuit.
(2) Large-Sized, Speaker System
The speaker, the 12-cm diameter of which is best in this
class of tape recorder, produces lush, comfortable, dy-
namic sound.
(3) Large-Sized Tripple Meter
The easy-to-read, large-sized meter indicates a battery
voltage in the tape playback operation, a tuning state in
a radio program reception, or a VU in any recording
operation.
(4) Matrix Stereo System
The main signal is mixed with the out-of-phase signal
which is taken from the other channel and passed
through a filter having a certain bandwidth. This makes
the reproduced sound by far deeper and wider than
usual, thus providing rather high stareophonic effect.
(5) Powerful Output
The output power is as high as 4.4 watts, 2.2 watts for
each channel at 4-Q load.
(6) Variable Sound Monitor
In recording a radio program, the sound volume and
tone can be freely changed without affecting the record-
ing level.
(7) Total Shut-off Mechanism
The tape is automatically stopped at the end in the play-
back, fast forward, or even recording mode of operation.
(8) Cue and Review Mechanisms
(9) One-Touch Recording System
Recording can be made by pressing the REC button only.
(10) Large-Sized Chassis
The large-sized chassis facilitates easy adjustment at any
point when the casing is removed. The number of screws
are minimized and the power transformer, external jacks,
meter, and similar devices are fit-assembled so that main-
tenance and service are very easy.

CRS-2104
2. DISASSEMBLY
2.1 REMOVING THE CASSETTE COMPARTMENT LID 2.3 REMOVING THE CHASSIS
While pressing the point A and B in the arrow direction, 1. Remove the five knobs A through E.
pull the lid toward as shown. The lid will be removed.
. Remove the five screws 1 through 5.
. The top escutcheon (F) will be removed.
. Remove the two condenser microphones (G) from
the front side by opening the stoppers toward the
arrow direction.
. Then the chassis will be removed.
NOTE:
The knobs of the FUNCTION, MODE, and AFC
switches should be replaced after putting the inside
white kips on the switch schafts.
2.2 REMOVING THE BACK COVER
1. Open the battery compartment cover by depressing 2. Disconnect the antenna lead connector A, and the
the finger grip and pulling down. Remove the seven back cover will come off the casing.
screws 1 through 7.

CRS-2104
2.4 REMOVING THE MECHANICAL ASSEMBLY
1. Remove the four screws 1 through 4.
2. Disconnect the lead connector from:
a) REC/PLAY HEAD, b) ERASE HEAD,
c) MOTOR SWITCH, d) MOTOR
3. SERVICE GUIDE
3.1 BATTERY VOLTAGE
Many customers often determine that the set is faulty
when malfunctioning as they are not aware of used-up
battery. Before operation, therefore, make certain that
the battery voltage is higher than 4.5 V.
3.2 BATTERY POLARITY
In loading the battery, particular care should be taken in
its polarity as wrong placing may damage transistors and
motor.
3.3 CLEANING THE HEADS
The head slit contaminated with tape chips and powder,
rubber, dust, or dirt leads to insufficient sound volume
and tone deterioration. Wipe such contaminants off the
slit using soft cloth moistened with alcohol or carbon
tetrachloride.
3.4 CURRENT CONSUMPTION
VOLUME
Maximum |
Minimum
Maximum
(rem oon
Minimum
_—__+—_—
*Units in mA.
The above values may differ slightly depending on
individual sets.
Measuring conditions (standard inputs)
Radio
AM: 5 mV, 400 Hz, 30% mod.
FM: 1 mV, 400 Hz, 30% mod.
Tape Recorder
Recording: 1 mV, 1 kHz at mic input
Playback: Test tape MTT 112 (333 Hz, 250
nwb/m)
3.5 VOLTAGE CONVERSION
This unit may be converted to 110 V operation by the
Voltage Selector Switch (S002) Located within the Bat-
tery Compartment.

CRS-2104
4. DIAL STRINGING

CRS-2104
5. MECHANICAL ADJUSTMENTS
PRECAUTIONS: Prior to any adjustments, clean the head slits with soft cloth or cotton swab moistened with denatured
alcohol or carbon tetrachloride, and fully demagnetize the head, capstan and similar parts.
5.1 CHECKING THE PLAY OPERATION
5.1.1 CHECKING THE PLAY TIMING
It is normal that when the PLAY pushbutton is depress-
ed, the take-up reel table turns first, then the pinch rol-
ler is rotated. The reel table and pinch roller must not
start turning at the same time.
NOTE:
Make certain that such a subsequent operation is mode
irrespective of locking state is depressed slowly without
loading the tape.
Slowly depress the PLAY pushbutton, and the take-up
reel table will start turning. At that time, check to make
certain that a clearance between the pinch roller and
capstan is less than 0.5 mm.
5.2 ADJUSTING THE PAUSE TIMING
Set the recorder in the playback mode. Depress the
PAUSE pushbutton slowly, and the take-up reel will
pause. As that time, check to ensure that a clearance be-
tween the pinch roller and ranges from 0.2 to 0.5 mm. If
out of the range, adjust a bending angle of the pinch
roller bracket arm (part A).
NOTE:
To increase a clearance between the pinch roller and
capstan, decrease the angle (in the direction C). To de-
crease the clearance, increase the angle (in the direction
B).
5.3 ADJUSTING THE FAST FORWARD AND REWIND
TORQUE
Set the extended parts (B in the figure) of the torque
adjustment leaf spring (A in the figure) of the FF/REW
idler on any one of three stepping parts of the idler.
NOTE:
To increase torque, set the extended parts to the step-
ping part of “INCREASE” and to decrease it, set those
to the stepping part of ‘‘DECREASE”.
Adjusting range: 70 to 110 g-cm
5.1.2 ADJUSTING THE PLAY TIMING
If out of specification, bend the part of the pinch roller
bracket which faces the head chassis stopper. In the
figure shown, bend the part in the direction of A to de-
crease the clearance. To increase the clearance, bend the
part in the direction of B.
0.2~0,5mm t
CAPSTAN SHAFT
PINCH ROLLER
* HEAD CHASSIS STOPPER
NOTE:
After adjustment, check to be sure that the pinch roller
bracket does not contact the head chassis stopper in
PLAY mode.
INCREASE DECREASE
A ret
WII

5.4 ADJUSTING THE PINCH ROLLER PRESSURE
Measure the pressure of the pinch roller using a gauge as
shown. For measurement, draw the pinch roller in the
arrow direction in which it is detached from the capstan
shaft and gradually return it toward the capstan. Read
the gauge at the time when the pinch roller starts turning.
The standard pressure is 300+50 g. If the pressure is out
of the range, bend the pinch roller spring aroung the
point A in the direction B or C.
5.5 ADJUSTING THE PLAY TORQUE
Mount
the
extended
parts
A
(two)
of
the
disc
leaf
spring
on
any
one
of
the
stepping
parts
of
the
idler.
Adjusting range: 40 to 70 g.cm
NOTES:
(1)
To
increase
torque,
mount
the
extended
parts
on
“INCREASE”
and
to
decrease
torque,
mount
them
on
“DECREASE”.
(2)
Check
the
take-up
clutch
for
slipping.
When
the
reel
base
is
paused,
the
wheel
must
smoothly
rotate.
The
wheel,
when
irregularly
rotating
or
stopping,
is
not
ac-
ceptable.
5.6 ADJUSTING THE FLYWHEEL THRUST
Adjust the thrust screw at the flywheel bracket until the
clearance between the capstan tail end and thrust bear-
ing is 0.1 to 0.3 mm as shown, using a phillips screw
driver. For adjusting, feel of axial dropping of the fly-
wheel for proper clearance as this cannot been seen
through. Then paint the screw to lock.
4 ————
a a |
eT
Y
CRS-2104
NOTE:
To make the pressure strong, bend in the direction B. To
make the pressure weak, bend in the direction C.
INCREASE DECREASE
et
P222~7 rsa
ADJUSTING
SCREW

CRS-2104
6. ELECTRICAL ADJUSTMENTS
5.7, POSITIONING THE MOTOR PULLEY AND MEASUREMENTS
Check to ensure that a clearance between the DC motor
and pulley is 3.1 mm. !f out of specification, reposition Precaution for Adjustment and Measurement
the pulley as shown. 1. Whenever adjusting or measuring any circuit, wipe the
heads clean with a soft cloth moistened with alcohol
or carbon tetrachloride. Also be sure to demagnetize
the heads, capstan, and similar parts.
2. The voltage at any electrical point may vary with the
input signal, so make measurements of voltage under
no signal condition.
3. Transistors are affected by microvoltage. Whenever
measuring on them, use aVTVM having a high internal
resistance and high input sensitivity enough to elimi-
nate errors in measurement.
4. In adjustment or measurement, set the TONE control
to its mechanical center (‘‘0’) unless otherwise spec-
ified.
5. For measurements of outputs, connect a pure 4 22 re-
sistor across the external speaker terminal and use a
VTVM. Unless otherwise specified, adjust the
VOLUME control for the standard output level, 50
mW (0.45 V/4 QQ).
5.8 ADJUSTING THE TAPE SPEED
Play the 3 kHz test tape back, and check to make sure
that the meter pointer of a measuring instrument (fre-
quency counter) indicates 3000 Hz +2.5% or less as spec-
ified. If it is out of the range, adjust the semifixed re-
sistor inside the motor. After adjustment, be sure to
stick seal on the hole for the resistor.
6.1 ADJUSTING THE PLAYBACK LEVEL
Play the 333 Hz level adjusting tape MTT 112 back and
inspect the R and L channel output voltages at the EXT
SP 4 Q jack. Adjust R804 until the output voltage of the
R channel coincides with that of the L channel. The out-
put voltage at EXT SP 4 2. jack will be around 0.45 V.
PE py) are
PLAYBACK LEVEL.”
C803 0.02/50V
R806 50k (D)
R803 2.7 k