Marantz SD 8000 8020 Service Manual

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MARANTZ MODEL SD8000 STEREO CASSETTE DECK

INTRODUCTION

This service manual are prepared for use by Authorized
Warranty Station and contains service information for
Marantz Stereo Cassette Deck.

Servicing information and voltage data included in this
manual are intended for use by the knowledgeable and
experienced technician only. All instructions should be
read carefully. No attempt should be made to proceed
without a good undestanding of the operation of the
Cassette Deck.

The parts list furnishes information by which replacement
parts may be ordered from the Marantz Company. A
simple description is included for parts which can be
usually obtained through local suppliers.

. P.W. BOARD

As can be seen from the circuit diagram, the chassis, of the
Model SDSOOO consists of following units. Each unit
mounted on a printed circuit board is described with in the
square enclosed by bold dotted line on the circuit diagram.

Pre-Amp .......... mounted on P.W. Board PK11
Misfit Line Vol ..... mounted on P.W. Board PK12
Output Vol ........ mounted on P.W. Board PK13
Power Supply ...... mounted on P.W. Board P400
Computer ......... mounted on P.W. Board PK21
Remote Jack ....... mounted on PVW. Board PK26

Digital 81 Meter LED . .
Program Selector . . , .

mounted on P.W. Board PK22
mounted on P.W. Board PK23

Program .......... mounted on P.W. Board PK27
Timer Switch ....... mounted on P.W. Board PK24
Rec Mute Switch . . . . mounted on P.W. Board PK25
Relay ............ mounted on P.W. Board P800
Photo Cuppler ...... mounted on P.W. Board P001

mounted on P.W. Board PK31
mounted on P.W. Board PK32

PK33
FF. Rew Gavernor . . . mounted on P.W. Board PMO'I
FuselP or N) ....... mounted on P.W. Board P900

Mecha Logic Switch . ,
Sensor Stop Switch , . .

We "Wu... )1) V106

.1,

aaslm'

2.TEST EQUIPMENT REQUIRED FOR SER-

VICING REPLACEMENT

For measuring and checking the Model 50-80001 the fol
lowing instruments and materials are necessary.

I Audio Oscillator (AF OSC)

o Attenuator (600 ohm)

O VTVM

D Distortion Meter

C Oscilloscope

O Bandpass Filter

0 Wow and Flutter Meter

0 Torque Meter (Cassette Type)

0 Digital Frequency Counter

0 Blank Tape lCompletely erased with bulk eraier)
* A0211 (Normal)
AC-SIl (CrOzI
CS-BD (Fe-Cr)
A0701 (Metal)

NOTE: If any doubt is noted in a measures value, use
a new tape,

0 Test Tape (New Tape)
MTT-Hl ,.. . Wow and Flutter. Tape Steed.
MTT-212 . Measurement of output lexel and
(MTT-112l Signal to Noise Ratio.
MTT»150 . Adjustment of output leve:
MTT-ZIG . Measurement of Frequency Response
lMTTei 16Ul (For Normal)
MTT-316 . Measurement of Frequent) Response
(MTT-116Kl (For 002, Fe-Cr)
MTT-121 . . . , Cross Talk.
MTT-141 . . . . Channel Separation.
MTT-l 128 . Playback $ignal~to-Noise Fittio.

(W.T.D. only)

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. This signal is amplified by 0505 and fed to the DC
clamping circuit via the response speed control R519
to shift the input signal from R519, which is deflect-
ing in both the positive and negative directions with
respect to 0V, to the positive side without changing
its amplitude.

. The DC shifted signal pulses pass through emitter
follower 0506 to charge C503 and C513 in the time
constant circuit

When recorded tape is being played back, charging
pulses are continuously applied to C503.

. When the signal is present, the charging voltage at
0503 is about 0.63V. 0508 and 0509 in the Schmitt
circuit are ON and OFF, respectively; 0501 is ON

while 0509 is OFF Pin 35 of the microcomputer is .

at low level.

'. When left and right channel play signals are not we

sent, the pulses charging C503 stop so 0503 dis-
charges into the Schmitt circuit via R523.

When the potential of C503 drops to about 0.55V,
the Schmitt circuit is inverted and 0501 turns off.
As a result, a program detected" signal is applied
to Pin 35 of the microcomputer.

in the PLAY mode, the program detection time re-
quired to apply a detecting signal after the play signal
stops is about 2.5 seconds (in other words, a blank
space of about 3-5 seconds is required between pro-
grams).

. in the CUE/REVIEW mode, the tape runs at a high
speed, so the program detecting time needs to be
reduced. In this case. C507 is turned on to discharge
C503 and 0513 through R525 and 0507 so that a
detecting time of about 30 mSec to 40 mSec is ob-
tained.

. in the CUE/REVIEW mode, if the tape speed varied,
the detecting time would vary, resulting in failure to
detect programs.

To prevent this, the reel motor is servo controlled
to maintain a constant tape speed.

.Control R519 is used to adjust the amplitude of the
pulses fed to the rectifier circuit. By changing the
pulse amplitude, the charging voltage of the time
constant circuit is varied together with the detect-
ing time.

. Recorded signals of which level indicated with the
peak level meter exceeds -35 dB are judged as pro-
gram signal.

The signal level can be adiusted with R615.

15

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5. MECHANICAL ADJUSTMENT

1. Brake Timing Adjustments

1. Remove the cover.

2. Adios-t by bending portion (A) of the brake lever
(075M so that brake timings of the supply and take-
up sides coincide with each other.

3. Set brake lever clearances to approximately 0.5 mm
on both the supply and take-up sides.

0.5mm

BRAKE LEVER

2. Back Tension Adjustments

1. Alter the spring Iomtion, (1i, (2), or (3), so that the
back tension is between 3.59 and 69.

BACK TENSSION ,
£5? /

3. Play Torque Adjustment
Put the two pawls of the circular plate spring on proper
stepped position of the reel rest. The adjustable torque
range is 40 to 70 g-cm.
To make the torque high, put the pawls on a shallow
step. For lower torque, put them on a deeper stat).
Torque can be adjusted by shifting position of the spring
P/N 4397115040.

The torque ranges from 40 to 70 g-cm.

DECREASE

SFfilNG
INCREASE

4. FF and REW Torques are not Adiustable

If FF or REW functions are inadequate, renew the
entire block, P/N 4397002420.

When the motor (Reel motor M002) is worn. FF and
REW modes may not function properly. In such a
case, renew the motor.

t

5. Pinch Roller Pressure

3309 t 509

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 3309 i 509.

PINCH ROLLER

39mg

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