Marantz SD8020 User 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
Mode! SD8000 consists of following units. Each unit
mounted on a printed circuit board is aescribed with in the
square enclosed by bold dotted line on the circuit diagram.
Pre-Amp.......... mounted on P.W. Board PK11
Mic& 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 P.W. Board PK26
mounted on P.W. Board PK22
mounted on P.W. Board PK23
Digital & Meter LED ..
Program Selector ....
Progam .......... mounted on P.W. Board PK27
Timer Switch... 2... mounted on P.W. Board PK24
Rec Mute Switch . . mounted on P.W. Board PK25
Relay 2.2 eat es mounted on P.W. Board P800
Photo Cuppler ...... mounted on P.W. Board POO1
Mecha Logic Switch .. mounted on P.W. Board PK31
Sensor Stop Switch . .. mounted on P.W. Board PK32
PK33
FF. Rew Gavernor ... mounted on P.W. Board PMO1
Fuse(PorN)....... mounted on P.W. Board P900
tompudeck SL NIOG
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2. TEST EQUIPMENT REQUIRED FOR SER-
VICING REPLACEMENT
For measuring and checking the Model SD-8000, the fol:
lowing instruments and materials are necessary.
® Audio Oscillator (AF OSC)
@ Attenuator (600 ohm)
e VTVM
® Distortion Meter
@ Oscilloscope
@ Bandpass Filter
@ Wow and Flutter Meter
@ Torque Meter (Cassette T ype)
® Digital Frequency Counter
® Blank Tape (Completely erased with bulk eraer)
bs AC-211 (Normal)
AC-511 (CrO2)
r CS-30 (Fe-Cr)
AC-701 (Metal)
NOTE: If any doubt is noted in a measureé value, use
a new tape.
@ Test Tape (New Tape)
MTT-111 .... Wowand Flutter. Tape Sped.
MTT-212 . Measurement of output lew! and
(MTT-112) Signal to Noise Ratio.
MTT-150 . Adjustment of output levei
MTT-216 . Measurement of Frequency Response
(MTT-116U) (For Normal)
MTT-316 . Measurement of Frequency Response
(MTT-116K) (For CrO2, Fe-Cr)
MTT-121 .... Cross Talk.
MTT-141 .... Channel Separation.
MTT-112B - Playback Signal-to-Noise Rytio.
(W.T.D. only)

TABLE OF CONTENTS
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2.
TEST
EQUIPMENT
REQUIRED
FOR
SERVICING
REPLACEMENT
.........................22...
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SCURCUIT-DESCRIPTION:
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CIRCUIT
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RECORDING
CURRENTSETTING
CIRCUIT
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COMPENSATING
CIRCUIT
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3.5
BIAS
OSCILLATOR
CIRCUIT/ERASE
OSCILLATOR
CIRCUIT
...........
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3.6
CONTROL
CIRCUIT
OPERATION
.........
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DIAGRAM
AND
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LOCATIONS
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8.1.
Pre
Amp.
Assembly
(PK11)
Schematic
Diagram
and
Component
Locations
............
0000
ce ce
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44
8.2
Mic
Line
Volume
Assembly
(PK12)
Schematic
Diagram
and
Component
Locations..............-.c0ccceccee
44
8.3
Output
Volume
Assembly
(PK13)
Schematic
Diagram
and
Component
Locations
.............-..cccceecee
44
8.4
Computer
Assembly
(PK21)
Schematic
Diagram
and
Component
Locations
............0
000 ccc
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47
8.5
Program
Selector
Assembly
(PK23)
Schematic
Diagram
and
Component
Locations..............0cc0ceeeeeee
49
8.6
Power
Supply
and
Bias
OSC
Assembly
(P400)
Schematic
Diagram
and
Component
Locations.................-..
50
8.7
Digital
and
Meter
LED
Assembly
(PK22)
Schematic
Diagram
and
Component
Locations
...............e0ce0ee
50
8.8
Timer
Switch
Assembly
(PK24)
Schematic
Diagram
and
Component
Locations.
.............
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51
8.9
Rec-Mute
Switch
Assembly
(PK25)
Schematic
Diagram
and
Component
Locations.
..............-0cecccccee
51
8.10
Program
Select
Assembly
(PK27)
Schematic
Diagram
and
Component
Locations
.............0.
0c
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52
8.11
Logic
Control
Assembly
(PK31)
Schematic
Diagram
and
Component
Locations...
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8.12
Remote
Jack
Assembly
(PK25)
Schematic
Diagram
and
Component
Locations
............00.
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8.13
Safety
Switch
Assembly
(PK32)
Schematic
Diagram
and
Component
Locations.
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8.14
Safety
Switch
Assembly
(PK33)
Schematic
Diagram
and
Component
Locations...............-00cecceccecae
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8.15
Timer
Relay
Assembly
(P800)
Schematic
Diagram
and
Component
Locations.............00
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8.16
Fuse
Assembly
(P900)
Schematic
Diagram
and
Component
Locations
(N,
TASB
VERSIONS
ONLY)
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Governor
Assembly
(PMO1)
Schematic
Diagram
and
Component
Locations
..............-0.e0ccceeee
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8.18
Photo
Coupler
Assembly
(P001)
Component
Locations...
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CIRCUIT DESCRIPTION
3.1 TAPE SPEED SELECTOR
Tape
speed
is
changed
by
switching
the
motor
speed
to
1,800
rpm
for
1-7/8
ips
(4.75
cm/sec)
or
to
3,600
rpm
for
3-3/4
ips
(9.5
cm/sec).
In
fast-forward
or
rewind
opera-
tion, however, the motor always rotates at 1,800 rpm.
1. R352 is used for precisely adjusting the motor speed
to 3,600 rpm.
2.To precisely adjust the motor speed to 1,800 rpm,
turn the variable resistor built-in the motor.
NOTE:
The
motor
speed
is
known
by
playing
back
the
test
tape
MTT-111
and
measuring
the
reproduced
frequency.
a,
'
Motor
speed
(rpm)
Reproduced
frequency
(Hz)
|
1800 3000
| 3600 6000
2350 R35!
z = ANA AA
RED WEL Ee
SZ puy (woorjve, oh M4_g e382
= SoS gga PM 93-3,
1-7/8 MOTOR SPEED ADs
H! SPEED Sou;
3.2 PLAYBACK EQUALIZER CIRCUIT
The playback equalizer circuit is shown below.
$103 Tape Speed Switch
$104 Tape Selector Switch (Normai)
Time constants of the playback equalizer circuit at each
tape speed and selector position are as follows:
TAPE SELECTOR | ogayq, SPECIAL! | |
position NORMAL “'c.g, FeCr | METAL
TAPE (1-7/8 1PS| 120uS | 70uS 7204S | 70 us
t $—— + +
SPEED (3.3/4 1PS| 70uS 35uS , 35uS | 36uS |
Circuit Function at Each Time Constant
(1) 120 pS
S104 is Tape Selector Switch for normal position.
In the diagram, this switch is in the depressed posi-
tion, causing Q103 and Q104 to turn OFF due to
zero bias voltage. In this case, the playback time
constant is set to 120 uS by C106 and R111 ~R113.
(2) 70 pS
When the tape speed is 1-7/8 ips (4.75 cm/sec) and
S104 is OFF (S104 turns OFF when the other tape
selector switch is depressed), a bias voltage is applied
to the base of 0104 which is then turned ON. When
the tape speed is 3-3/4 ips and S104 is ON, 0104
is also ON. In either case, the playback time constant
is set to 70 pS by C106, R111 ~ R113, C114 and
R118.
(3) 35 uS
When the tape speed is 3-3/4 ips (9.5 cm/sec} and
S104 is OFF, Q103 is ON and the playback time
constant is set to 35 uS by C106, R111 ~ R113,
C111, C112 and R116.
3.3
RECORDING
CURRENT
SETTING
CIRCUIT
Recording
currents
at
each
tape
speed
and
each
position
of
the
tape
selector
switch
are
determined
by
the
follow-
ing
circuit:
$103 Tape Speed Switcn
$104 Tape Selector Normal
$105 Tape Selector Special,/Cr =
S107 Tape Selector Metal
The switch (S106) for the FeCr position is not inclujed in
the above circuit. The recording current at this position
is determined by R155 and R149 or R154 and 3148.
The resistors used to determine recording current a each
tape speed and each tape selector switch positim are
shown in the table below.
oe
TAPE SELECTOR | SPECIAL:
BECTON NORMAL | Cr0, FeCr | MEAL
- :
R155, R151 R155, R153 | R155
1-7/8 IPS |
TAPE I8PS;"R149—«| R149 niag: SS
SPEED (R154, R150/R154, R152 | R154
[33/4 1S R148 R148 Riag | R48

3.4
RECORDING
COMPENSATING
CIRCUIT
(Tape
Speed:
3-3/4
ips)
oA t
$103 Tape Speed Switch
S105 Tape Selector Switch CrO2
S107 Tape Selector Switch Metal
In
the
circuit
diagram,
C150
and
R163
are
used
for
high
range
compensation.
L104,
R168,
R169, R170,
R171
and
C154,
C155,
C156,
C157
form
a
peeking
circuit.
Peeking
frequency
and
the
amount
of
compensation
are
selected
by
the
tape
selector
switch,
R165,
R193
and
C153,
C166
are
used
for
medium
range
compensation.
The
amount
of
compensation
is
selected
by
the
tape
selector
switch
(not
available
at
‘‘Normal”’
position).
3.5
BIAS
OSCILLATOR
CIRCUIT/ERASE
OSCILLATOR
CIRCUIT
The
SD8000
has
a
bias
oscillator
circuit
and
an
erase
oscillator
circuit
to
provide
optimum
bias
and
erase
cur-
rent for the use of metal tapes.
@
The
bias
oscilator
circuit
is
driven
by
a
regulated
amp-
lifier
power
supply.
e@
The
erase
oscillator
circuit
is
driven
by
the
motor
power
supply.
The
bias
current
for
any
particular
type
of
tape
is
selectable
by
the
circuit
shown
below
(selection
of
bias
current
is
independent of tape speed).
1. Bias Oscillator Circuit
As
shown
bellow,
sy
varying
the
Q302
base
voltage,
the
bias
oscillator
circuit
operational
voltage
is
altered.
In
case
of
4-3/4
i.p.s.
(9.5
cm/sec),
do
not
adjust
by
bias
current.
Adjust
the
recording
EQ
circuit,
instead.
Inci-
dentally,
R310
is
the
bias
fine
adjust
control
on
the
front panel.
QR
<0
S23ig9
$936
ne oe
aceecnamiaes ces
| Normal CrO2 | FeCr | Metal |
——
ivihips ORAIE Gua
(4.75cm/s)i R410 ice Mae se a
aoe, pic a a i
2. Erase Oscillator Circuit
The
erase
oscillator
circuit
consists
of
Q417
and
T402.
Only
in
case
of
meta!
tapes,
R305
is
shortedto
increase
the erase current.
JsSe
SI07-@ 5102-3
Metal Rec/Hay
Switch

3-6. CONTROL CIRCUIT OPERATION
1.
General
2.
Microcomputer
The
SD8000
tape
deck
is
designed
to
have
a
wide
variety
Terminal
arrangement
(front
view)
of
functions
such
as
time
setting,
timer
setting,
program-
ming,
counter
function
and
memory
function;
all
these
are
accomplished
by
a
single
1-chip,
4-bit
microcom-
puter
element
uPD546C.
Although
the
microcomputer
performs
complex
func-
tions,
the
control
circuit
is
extremely
simple.
In
the
microcomputer,
the
memory
and
control
func-
tions
are
processed
together
at
high
speed
through
the
levels
and
timing
of
digital
pulses
available
at
input
and
output
terminals.
Since
this
instruction
manual
is
limited
in
space,
it
is
impossible
to
explain
in
detail
the
methods
of
measuring
°
“PD346C
and
checking
the
relationship
between
the
input/output
:
0701
signals
and
their
timing.
Thus,
this
manual
is
intended
only
to
cover
the
functions
of
operation
buttons
and
matrix
keys.
The
SD8000
has
various
types
of
keys
and
switches
to
provide
multiple
operations,
so
special
care
should
be
taken
when
it
is
necessary
to
check
the
cause
of
trouble
or
misoperation.
This
manual
mainly
deals
with
the
functions
of
the
SD8000
control
circuit.
Note
that
voltages
and
operat-
ing
timing
given
in
this
manual
are
for
reference
pur-
poses
and
are
subject
to
change
according
to
changes
in
power
supply
voltage
and
production
tolerance
of
CLO.1:
Clock
oscillator
LC
(external)
PE3-0:
Outputport
E3-0
components. INT: Interrupt RES: Reset PF3-0: Outputport F3-0
PA3-0: Input port A3-0 PG3-0: Outputport G3-0
PB3-0: Input port A3-0 PH3-0: Outputport H3-0
PC3-0: Input/output port C3-0 PI2-0: Outputport !2-0
PD3-0: Input/output port D3-0 TEST: Test
Fig. 2.1 Terminal arrangement (front view)
Block diagram
UP/DOWN INSTRUCTION BUS &b
PL.
ae,
COUNTER
ee
; 7
, RAM Cs An
PH. ti eee f DECODER oo
y fay
id CONTROL
a
DECODE
i) RAM [
BUFFER , oy,
STACK 2
Clo?" CLOCK 6 é
CL 0~ GENERATOR INT RES DP: Data pirtter
ALU: Operator unit
ACC: Accum} ator
PC: Progran «<ounter
Fig. 2.2 Block diagram ce rudd i
Pe:.
INTERRUPT
CONTROL.
1.0
INTERFACE
PA.-

Table 2.1 Functions of input/output signals
f Te =
j No. Signal Function
: 1 cul Clock 1 Pin 1 on clock oscillator LC
2 PCO £.)
3 PCI Input/output Fl
4 PC2 port C
5 PC3 H
Description
iape end)
of Keyboard strobe signal anc 7-segment lamp signal
T
Remarks
Not used as input
terminal.
6 INT Interrupt input Counter pulse input ‘detects
7 RES Reset input Initial reset inout
8 PDO A.
Operation button strove signal }
9 Pot input/output 2 perationucton:smeceeg Fission: arao tanal No used as input
ie port D oe Keyboard strobe signa! terminal.
: Lamo signal, PM, ERROR tamp strobe signai
12 PEO (4) SELECTOR control signal plete eee
13.
PE
Output
(3)
PROGRAM
MODE
controi
signal
lamp
signal
Jen,
14 PE2 port E (2) COUNTER MEMORY control signal “pm lamp, dis
15 PES (1) TIMER controt signal Signal’. tae
16 PFO TIMER ON LED iamo signal
17 PFI Outpur bert’ ® TIMER OFF LED iamo signal
18 PF2 me * REC LED lamp signal
19 PF3 PRG PAUSE LED 'amo signal
20 TEST Test inout Not used; connected to Vss
21 Vss Power supply +10V =1V
22 PGO TIMER ON signal
23 PGI TIMER LED iamo signat
24 PG2 Ourouriper'G RAM LED tamp signai
25 PG3 SAM LED iamo signat
26 PHO FAST \
27 PHI FR
28 pu? Output port H REW
29 PHS C/R(CUEREVIEW) | |
so i ee Oe as ape deck operation mode control
30 Plo PAUSE Toe
a Ply Output port t PLAY ‘
32 PI2 REC J
33 PAG Power frequency select sgnai
34 PAI i uRDOHEA Power sync signal
35 PA puter Program detect signai
36 PAQ Time cispiay seiect signal
37 PBO 4
38 PBI S
39 282 input port B rf Pragram signa! operation s.gnat
40 P83 VJ
41 Veg GND ov
42 CLO Clock 0 tock oscillator LC
Control signal input circuit Fig. 2.3 Control signal input circuit
W\y-—————— 9
R645 |
fr H Tt
!
Q646
Fl
———
137 a TOO
| WOO: \
-~o |; 3
nl a
AC IN
Without signai
of 10.2V)
tt +H2v : ‘
! Program With signal! (OV)
RMI5
detect signal
pelkisea
Q701
Sine wave
3.2Vpp/400 KHz
Input portA
APDS46C

The Items (1) through (8) below are basic requirements
for operating the microcomputer.
(1) Pin 1, 42
Pin 1 and pin 42 are the external terminals of the clock
oscillator LC. The internal circuits of the microcom-
puter must be synchronized with the clock signal for
proper operation. Incorrect oscillation of clock signal
will result in misoperation of the microcomputer.
The clock signal at pin 1 should be a sine wave signal
of about 3.2 Vpp/400 kHz (including a 7.6V DC com-
ponent).
(2) Pin 6
Pin 6 is the counter pulse input terminal. Pulses are
counted by the up/down counter in the microcomputer.
In the PLAY, FF or PAUSE mode, the pulses are
counted up; in the REW or REVIEW mode they are
counted down. When no counter pulses are preset at
this terminal and tape is being transported, the COUNT-
TER MEMORY will not function.
If the pulse input duration is less than 2.0 seconds, the
tape deck stops automatically.
(3) Pin 7
Pin 7 is the reset signal input terminal. When a high level
signal is applied to it, the internal circuits of the micro-
computer are reset and all functions stop.
Pin 7 becomes high level just after the power is con-
nected to the SD8000, regardless of whether the power
switch is ON or OFF. Under normal circumstances,
the voltage at Pin 7 is OV.
(4) Pin 20, 21
Pin 20 is a test terminal and Pin 21 is the power ter-
minal.
The test terminal is connected to the power supply
since it is not used. The power voltage should be +10V
t1V.
(5) Pin 33
This is an input terminal for the power frequency select
signal. The time signal of the SD8000 is obtained by
dividing the power frequency, so the frequency divider
in the microcomputer needs to be given the proper fre-
quency division ratio according to the power frequency
(50 Hz or 60 Hz).
When Pin 33 is OV (GND), the frequency division ratio
is 1/50, and when it is 10V, then the ratio is 1/60.
(6) Pin 34
This is the input terminal for the time and timer signals.
A pulse signal of 10V with the power supply frequency
should be applied to this terminal. Otherwise the cor-
rect time will not be indicated and the timer recording
function will not operate correctly.
(7) Pin 35
This is the input terminal for the program detection
signal. The programs to be played are controlled by the
applied signals. When the deck is in the playback mode,
this signal is OV for recorded portions of tape, and 10V
for blank portions between programs (where no signal
are recorded on the tape).
(8) Pin 36
Normally, a voltage of 10V is applied to this terminal.
When the voltage becomes OV, the display automatically
indicates the time.
(9) Pin 31
This is the GND terminal.

Fig. 2.4 Operation/program signal input circuit
_ 0583
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L_ Q70! wPOSSa6C i
Besides the signals outlined previously, there are the In the microcomputer, these signals are synchronized
input circuits for the operation signals (PLAY, FF, etc.) with the clock signal and processed together to deter-
to select the mode of operation of the SD8000 and mine the mode of operation with the aid of the opera-
for the program setting signal (START, SKIP, etc.). tion and program switches, input and output signals and
Refer to Fig. 2.4. their timing.
Operation/indication signal output circuit
Refer to Fig. 2.5
Fig. 2.5 Control/Indication signal output circuit
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Fairs
1
(1) Tape deck operation signal
This signal is delivered from output ports H and | to
determine the mode of operation of the tape deck.
For
example,
in
the
PLAY
mode,
a
high
level
signal
is
mutput by Pin 31 and the tape deck remains in the
3 Syd, ~
Output Output Sutue Gurus Gata anor
port! portH port G portF porte portD portc
Q701 uPD546C
PLAY
mode
as
Jong
as
the
signal
is
high
level
In
the
timer
recording
(or
playback)
mode,
a
high
level
signa!
is
output
from
Pin
22
of
output
port
G.
For
the
func-
tions
of
the
circuits
in
each
operating
mode,
refer
to
Section
4
‘Tape
Operation’’

3. Circuit
This
Section
is
intended
to
explain
the
functions
of
the
motors,
solenoids
and
related
circuits.
3.1 Motor and solenoid
(1) Play motor (M001)
This
FG
servo
DC
motor
is
always
rotating
while
a
cassette
is
loaded
and
drives
the
capstan,
i.e.
the
tape,
at
a
constant
speed.
Winding
torque
is
applied
to
the
right
reel
disk
during
the
PLAY
or
REC/PLAY
mode.
(2) Reel motor (M002)
This
FG
servo
DC
motor
is
used
to
set
the
tape
in
FF,
REW
or
CUE/REVIEW
mode
(CUE
and
REVIEW
are
performed
in
the
fast
forward
and
rewind
modes
res-
pectively
while
programs
are
being
played).
tn
each
mode,
the
tape
speed
is
maintained
constant
by
means
of
the
servo
control
system
of
the
motor.
The
reel
motor
rotates
in
the
reverse
direction
when
the
deck
is
changed
from
the
fast
forward
mode
to
the
rewind
mode.
Either
the
left
or
right
reel
disk
is
driven
according
to
the
direction
of
the
motor.
The
reel
motor
is
also
used
to
remove
slack
in
tape.
(3)
Play
solenoid
(L001)
This
solenoid
functions
when
the
deck
is
in
the
PLAY
or REC/PLAY mode.
a.
The
head
base
is
lifted
and
the
head
contacts
the
tape.
b.
The
pinch
roller
contacts
the
capstan
and
the
tape
starts
running.
c.
Slight
braking
is
applied
to
the
left
reel
disk
to
pro-
vide
back
tension
to
the
tape.
d.
The
fast
forward
idler
is
set
in
the
neutral
position.
(4) Brake solenoid (L002)
This
solenoid
functions
when
the
deck
is
in
the
PLAY,
REC/PLAY,
FF,
REW,
or
CUE/REVIEW
mode.
When
it
operates,
the
eft
and
right
reel
disks
are
released
to
drive
the
tape.
(5) CUE/REV solenoid (L003)
This
solenoid
functions
when
the
deck
is
in
the
CUE/
REVIEW,
PAUSE
or
REC/PAUSE
mode.
In
the
CUE/REVIEW
mode,
the
head
base
ts
lifted
up
to
its
middle
position
to
permit
the
tape
to
contact
the
head.
In
the
PAUSE
or
REC/PLAY
mode,
the
capstan
is
released
from
the
pinch
roller
and,
at
the
same
time,
the
play
idler
is
disengaged
from
the
ree!
to
stop
tape
movement.
(6)
Recording
solenoid
(L004)
This
solenoid
functions
when
the
tape
is
in
the
REC/
PLAY
or
REC/PAUSE
mode
to
set
the
amplifier
to
the
recording
mode.
When
this
solenoid
is
inoperative,
the
amplifier
is
in
the
playback
mode.
3.2 Back-up Circuit
When
the
power
switch
is
OFF,
back-up
power
{s
Sup-
plied
to
the
microcomputer
via
T0002,
rectifier
(0419,
0424)
and
voltage
regulator
circuit
(Q421
~
Q423).
In
this
case,
the
voltage
at
Pin
36
of
Q701
is
OV,
thus
time
is
indicated
on
the
display.
During
back-up
operation,
the
programs
stored
in
memory
remain
uncleared.
3.3
Solenoid
drive
voltage
select
circuit
The
SD8000
is
equipped
with
4
solenoids.
To
ensure
proper
operation
of
these
solenoids,
a
sufficient
drive
current
is
required.
If
a
large
current
flows
into
a
solenoid,
the
solenoid
is
overheated
which,
in
turn,
increases
the
winding
resist-
ance
and
reduces
the
force
of
attraction
of
the
solenoid.
However,
once
the
solenoid
has
been
operated
with
a
large
current,
it
operates
stable
even
with
a
retatively
small
current.
The
SD8000
employs
a
solenoid
drive
voltage
select
circuit
to
select
the
operating
voltage
according
to
whether
the
solenoid
is
in
the
operating
mode
or
holding
mode.
Fig.
3.1.
and
Fig.
3.2
show
the
operating
principles
of
the
circuit
in
the
PLAY
mode.
Fig.
3-1
Solenoid
drive
voltage
select
circuit
ease LUE, REY REC
Shad ea
ie. Be ae ap are
se = leanne eerie
BG Q004
ag
ee
2822
|
are
Pras
yi
Bette
a
ree
L!
1:8
'
+
-
#as67
7
eee
—
aces
pa
.
pris
004
a
oot
—
eae
Qs29 wtee ah 525
Q ws
Det
t=)
+“)
&
-&—
Fig. 3-2 Solenoid operation
PLAY
4
f
signal
:
OFF
Q529
ON
Q534
pase
eee
SS
__————_—-
aQ534
ON
OFF —
Q533
ON
__|
_____—
22V
Q532
Base
\2V
|
ev
ij
20V
Q432 Emitter lev 10V
PLAY solenoid
L001 (both ends)

(2) Indication signal — 1
This signal is delivered from input/output ports C and
D and output port E to drive the 7-segment LED, PM
LED and OVER-FLOW LED in the display. For ex-
ample, the following steps are taken for the display to
indicate 1:24’. Refer to Fig. 2.6.
a. Strobe signals (1) through (4) are output from output
port E, lighting the 7-segment LEDs one by one
starting from the top digit.
b. The 7-segment lamp signals are output from output
ports C and D.
c. The lamps of all the digits will light in sequence, but
they appear to light simultaneously because the driv-
ing cycle is very short.
Fig. 2-6 Principle of displaying “1:24”
Q70I-i8 i) J i
oe eae
Q70I-14 2) ——— ;
Q701-13 3) re Se are
Q7O01- 52
(rw
@)
m ee
Q70i-2
7
Q70I-2
Q70I-4 3 {ci Zs: [espe al
Q7O0I-o B tft ee werner ieee
Q7?OlRA1: OO pes Ls LE Le
(3) Indication signal — 2
The LED ifamp signals, used to indicate the mode of
Operation of the microcomputer, are output from out-
put port F and output port G (excluding Pin 22).
The conditions required to light the LEDs are given in
section 5 “Programming”.
The Q702 and Q703 (uPA57C) are wired as shown in
Fig. 2.7 to serve as a buffer driver.
Fig. 2-7 uPA57C
1g 13 12 lt 10 9 8
MPAS?7C

Fig. 3-3 Tape end detect circuit
a. The PLAY signal level in the output of the micro-
computer rises to ‘‘H” (this signal turns on 0529 and
Q527 through a circuit via a separate route). (Fig. 3-1)
b. The PLAY signal is differentiated, then passes
through Q569 and turns ON Q534 momentarily.
Q533 is OFF when 0534 is ON.
c. When 0533 is OFF, a bias voltage of about 22V is
applied to the base of Q532 through Zener diode
Q562. At this time, the output of the emitter of
Q432 is about 20V.
Since Q529 and 0527 are ON, a voltage of 20V is
applied to the PLAY solenoid LOQ1 and the BRAKE
solenoid LOQ2 and hence they are driven by a large
current.
d. When 0534 is OFF, 0533 is ON so the base of Q532
is biased by Q561. As a result, the bias voltage is
reduced to about 12V, causing the voltage at the
emitter of 0432 to be reduced to about 10V and thus
the solenoid is held closed at about 10V during the
PLAY mode.
3.4 Tape end detect circuit
+12V
RMI32 RMS
77
ao0o1
7 Photocoupler
Right reel disk
Light shield drum
Fig. 3-4 Tapedrive detect mechanism
Fig. 3.3 shows the counter pulse generator circuit which
also serves as the tape end detection circuit. Detection
of tape end is accomplished by the mechanism shown in
Fig. 3.4 When the right reel disk is rotating, the light
shield drum attached to the reel disk also rotates.
The light shield drum has two slits; photocoupler Q001
contains a light emission diode and a photo transistor.
The light from the light emission diode arrives at the
photo transistor only when the slits in the fight shield
drum pass through the photocoupler, energizing the
photo transistor.
When the light is blocked, the photo transistor is OFF.
In other words, the photo transistor turns on twice
for each rotation of the right reel disk. Since the photo
10
Tape slack
—
removal signai Bn 1 aR
transistor’s ON time is not stabilized and since it is de-
energized between ON and OFF according to the posi-
tion of the light shield drum, the waveform of the signal
must be shaped by the Schmitt circuit consisting of
Q545 and Q546.
As shown in Fig. 3.5, Q545 turns ON when the voltage
is below 1.3V. Operation of Q546 is the reverse of
Q545.
The shaped output waveform is applied to Pin 6 of
Q701.
When the output pulse from Q546 stops in the PLAY,
FF or REW mode, the microcomputer detects the end of
the tape and the tape stops 1.5-2 seconds later.
Fig. 3-5 Schmitt operation
OFF
Q545
ON
r
L3V 2.0V
Q545 Base Voitage
3.5 Reel motor drive circuit
(1) Reel motor driver Fig. 3-6 Reel motor driver
REEL MOTOR
MOO2
REEL MOT SR 2RIVE.
i
Hy is ©) RMO3 _.OM *aMO04 Servo
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, : amplifier .
yRMI2 | | RMOS Gane
— 40
amos : —owos Oo-
QmMcs
” - + +
cMO6 M07 QM08
gas Zpmio '
ted 7”
Q701 27 —~ FF
Q701 28 —~ REw
Under normal circumstances, QMO9 is OFF and the base
of QM10 is biased via RM12. The voltage at the emitter
of QM10 is about 14V (load). When a high level FF
signal is output from the microcomputer via 0701,
QMO6 turns ON via R570 and RMOY. This reduces the
signal level at the collector and thus QMO2 turns ON.
As a result, a current fiows into the base of QM0O5 which
will turn ON.
In the reel motor MQO2, a current flows along the route
QMO02 — M002 — QMO5 — QMO8 so that motor runs in
the counterclockwise direction (as viewed from the
pulley side) to drive the right reel disk.
The transistor QMO8 in the servo amplifier functions
as a variable resistor, controlling the reel motor current
to provide a constant tape speed (refer to Item 3-8
wey,
In the REW mode, QM07, QMO3 and QM04 turnON.
In this case, a current flows into M002 along the route
QMO3 — M002 — QM04 — OQMO8, so the motor runs in
the reverse direction of this FF mode.

(2) Servo circuit
b.
7 QMIO
Refer to Fig. 3.7 <B Q +
one: ! i i a
=
|
{
|
R570
a
Ipeseee
FF
(CUE)
——W—
t
‘
|
R569
0578
i
!
'
RE
WIRE
VIEW)
—\W—
P+
+
;
;
at
i : RMO| | (REEL
;
H
2
*
=
AW
———+
a
a
|
MOTOR
:
| if ewes ervey [RMSE * Tcmi3 HCMC8| =|, tcmog | ORIVER
SRM26
i
m.
l
‘
——4RMI5} us + ‘ I \ { MOO2
3
t
ig
:
i
|
REEL
MOTOR
ue 2 Sow RMI? QMi3, er 6 |
a on a
ae Fo =.
:
ore
be
Sy
el
|
;
(See
Fig.
3-6)
‘ 1 or
eo, ; ” ‘
eee por Fk H
=
H
acol
.
x
ed
Photo coupler
2006!
PHOTO COUPLER
Photocoupler Q001 is located on the right reel disk
and Q006 on the left reel disk.
In the FF mode, a high level signal from the micro-
computer passes through R507, RM26 and RM21 to
turn QM11 on.
The signal from QO01 is not applied to other circuits
as long as the tape is in the FF mode.
In the REW mode, QM12 is ON and the signal to
Q006 stops. (The FF mode operation is explained in
the following.)
In the STOP mode, CM14 and CM19 are uncharged,
so the base of QM19 is at the GND level. QM19 is
OFF and the collector voltage of QM19 is about
8.2V. When the FF signal of H level is output from
the microcomputer, CM19 is charged through RM26,
QM15 and CM14. The FF signal also biases QM19 for
about 150 msec via RM38. Therefore, QM19 is turn-
ed ON and CM15 is quickly discharged through
RM37 and QM18.
When the voltage (QM20 gate voitage) charged in
CM15 drops, the resistance across the drain and
source of QM20 is increased. With this resistance in-
creased, the DC output voltage from Pin 6 of QMO1
drops and the QMO8 collector current (reel motor
current) is decreased. Therefore, the reel motor starts
running at a slower speed just after entering the FF
mode. When CM14 is charged with the FAST signal,
QM19’s base voltage drops and the collector voltage
is increased. CM15 is charged through RM36 and
RM39 with a long time constant so CM20’s gate volt-
age is increased slowly. As the gate voltage is in-
creased, the drain-source resistance is decreased grad-
ally, while QMQ1’s output voltage is slowly increased.
Thus, QMO8‘s collector current is increased, thereby
11
Fig. 3-7 Servo circuit
increasing the speed of the reel motor gradually.
Since the ree! motor starts running at a slow speed,
the tape will not become slack.
d. In the FF (REW) mode, the tape drive detecting
signal is fed from QM14 (QM13) to Pin 4 of QM21.
QM21 (uPD4528C) is a unistable multivibrator which
Outputs low level pulses with a width of about 2
msec, from Pin 7 at the rise of the trigger pulses given
to Pin 4. The pulse-width is determined by the power
voltage, CM16 and RM44. Refer to Fig. 3.8 for the
connection of uPD4528C and its block diagram.
Fig. 3-8-1 Reel motor rising characteristic
H
FF signal
Li
H he og
cCM14© NY
L 17
H
b
QmM19
Collector
QM20 Gate
QM01-6
Reel motor HIGH a an
speed
Moo2 STOP

.
The
output
of
QM21
is
rectified,
smoothed
and
ap-
plied
to
the
base
of
QM19
as
a
speed
control
signal.
The
functions
of
the
servo
motor
in
the
FF
mode
are
as
follows:
*
At
the
start
of
tape,
the
Jeft
reel
rotates
at
a
slow
speed
because
there
is
a
large
amount
of
tape.
When
the
tape
on
the
left
reel
is
decreased,
the
speed
of
the
reel
is
increased
gradually
and
the
interval
of
the
input
(trigger)
pulses
from
Pin
7
of
QM21
becomes
shorter.
With
the
trigger
pulse-interval
becoming
shorter,
the
interval
of
the
output
pulses
from
Pin
7
of
QM2?1
also
become
shorter.
The
interval
of
the
pulses
which
are
differentiated
by
CM17
and
fed
to
the
rectifier
circuit
become
shorter,
so
the
output
voltage
of
the
smoothing
Circuit
is
increased
which
increases
the
voltage
at
the
base
of
QM19.
With
the
QM19
base
voltage
increased,
the
col-
lector
current
is
increased,
decreasing
the
collector
voltage.
Thus,
the
voltage
at
the
gate
of
QM20
is
lowered,
With
the
gate
voltage
lowered,
the
drain-source
resistance
is
increased,
lowering
the
QMO1
output
voltage
which
decreases
the
QMO8
collector
cur-
rent.
The
QMO8
collector
current
is
the
current
flowing
into
the
reel
motor.
When
this
current
is
de-
creased,
the
motor
runs
at
a
slower
speed.
The
reel
motor
drives
the
right
reel
disk.
If
the
motor
were
to
run
at
a
constant
speed,
the
tape
would
run
slowly
at
the
beginning
of
tape
and
at
very
high
speed
at
the
end
of
the
tape.
The
servo
motor
is
used
to
make
the
tape
speed
constant
throughout
the
entire
length
of
the
tape
by
reduc-
ing
the
speed
of
the
reel
motor
while
the
tape
is
running.
Voo Tiz2 T22 Coz Az B2 Qe2 Q2
Top view
Tir Tzi Cor Ar Bi Qi Qi GND
Terminal connections
f. The pulse-width and voltages at the beginning and
end of tape are as follows:
Beginning | End of
| of tape tape 4
QM214 Trigger pulse interval | 50 msec 30 msec
CM19 “+"’ Smoothing cir- il
cuit output voltage 0.25V 0.62V
jo.
QM19 Collector voltage 8.8V 1.7V |
QM20 Gate voltage fo7evV.O.15V |
QMO8 Collector voltage | 5.8V. ‘| 7.8V
Reel motor speed | Fast ~_ [Slow
. The purpose of maintaining the tape speed constant
in every fast tape-feeding mode is to ensure stable
operation of the program detecting function ex-
plained in a later section.
. The semi-fixed resistor RM34 in Fig. 3.7 is used to
determine the maximum speed of the reel motor,
while RM48 is used to determine the range of speed
of the reel motor or the average speed of the tape.
Fig. 3-8 uPD4528C unistable multivibr ator
Voo Voo
Block diagram

3.6 Tape slack removal circuit
1OVv
CASSETTE P
R591
|
TO PLAY
Selenoid driver
MOO2 Real motor
!
ay Reel motor driver
proc ctee
; Servo -
i amplifier ;
; 1
i
I
t {
i 1
H
t
|
! {
i |
——_— |
I i QMOB |
|
| |
Sr tis ete ee ee ped ead
h ag ed
R569 Q57
If the tape in the cassette is slack, it can result in tangl-
ing of the tape in the tape drive mechanism. The
$D8000 is equipped with a tape slack removal circuit
which removes any slack tape automatically when a
Cassette is loaded in the tape deck or when the power
switch is set to ON (not when backup is power ON).
Refer to Fig. 3.9.
When the power of the tape deck is set to ON without
a cassette loaded, the cassette IN switch (S021) is open
and 0547 is OFF, but 0548 is ON.
When a cassette is loaded, S021 is closed and Q547 turns
on. The base of 548 is grounded through C524 and
Q548 turns off for about 1 second.
While Q548 is OFF, a high level signal is output from
the collector of Q548 to perform the following func-
tions:
(1) Q515 is switched ON via Q574 and R558 to drop
the PLAY signai level to L so that the deck is not
set in the PLAY mode until the slack in the tape is
removed.
(2)
QMO9
is
switched
ON
through
R691.
Therefore,
the
voltage
divided
by
RM11
and
RM12
is
applied
to
the
base
of
QM10,
then
the
emitter
output
voltage
of
QM10
drops
to about
8V
(at
unloaded
time).
As
a
result,
the
torque
of
the
reel
motor
is
lowered
to
prevent
the
tape
from
being
wound
more
than
necessary.
(3)
QMO7
is
switched
ON
via
R562,
Q579
and
RM10.
QMO3
and
QMO04
are
also
ON
and
the
same
direc-
tion
as
the
REW
mode.
The left and right reel disks are braked while the
tape slack is being removed, but less braking is ap-
plied to the left reel base than to the right ree! base
so the tape is wound onto the left reel with a low
driving torque as the slack tape is removed.
When the power is turned on with a cassette loaded
(for timer recording, etc.), slack tape is also re-
moved in the same way.
When the PLAY, FF, REW or STOP button is pres-
sed during the tape slack removal operation, the fol-
lowing functions are performed:
13
i Fig. 3-9 Tape slack removal circuit
(4) PLAY button
Q515 is switched ON and the PLAY signal level is
reduced. Slack tape is removed and the tape is set
to the PLAY mode after Q522 turns OFF.
(5) FF button
Q549 is switched ON via R579, releasing the tape
slack removal operation. The deck is set in the FF
mode.
(6) REW button
The deck is set to the REW mode immediately.
The torque of the reel motor remains low during
the slack tape removal operation.
(7) STOP button
The slack tape removal operation contrinues.
3.7 Tape Speed Selector Circuit
The tape speed in the PLAY or REC/PLAY mode is
determined by the speed of the capstan motor (M001).
This motor is servo controlled by its FG (frequency
generator). The speed is selected by changingthe series
resistor in the frequency generator.

3.8 Program Detector Circuit
Play head QIOI,QIO2 Play EQ amp.
l=
Fig.
3-10
Program
detector
circuit
block
diagram
Sensitivity eae -
Bae
i
Mixing
High-pass
a:
Amp,
@diuster
an,
filter
Amp.
—
Limitter-1
Amp.
Limiter-2
REIS —— ae
Q201,Q202 Of
Pee
+
cs01
e504
28
c505
e506
S94
cs0g
m4
Ce
>4
tH;
>
4
Ho
7H
608
ro?
R505
R506
bop
eH
Q608
|
Q555
os
Qs5i
9552
553
9554
Q626
LZ)
R503
pc
Time
Response
clamp
Emitter
cn
Schmitt
Amp.
speed
,————.
follower
circuit
adjuster
Q508,Q509
!nverter
Q505
|
Y
oni
Q506 cane
2501
+ Le eo
C5IO
cst
“}
+
|
0558
Q559
Bs
|
R519
C/R
eed
R525
35-29)
Q557
:
R524
:
aD
R520
Q701
Microcomputer
Q507
c503 “* C513
Fig. 3-11 Program detected signal
Program end
Mixing amp input
Limiter-1 output (C506@) |
0.6V H
-0.6V
Limiter-2 output (C510©)|
0.2V
2 FAR} —
-0.2V
0.6V
cersoo HE HT]
~0,6V
OC clamp output
(Q558 cathode)
a Ay [ |
Ov
0.63V
C5030 Program
. : O.55V
detection time
a
Play mode: About 2.5 sec.
Schmitt output . C/R mode: About 30 ~ 40 msec.
(Q509 collector)
HIGH —
LOW ee
Program detected signal (701-35)
LOW
HIGH
14
The program detector circuit detects blank spaces bet-
ween programs on tape and feeds a high level program
control signal to pin 35 of the microcomputer. Fig. 3.10
is a block diagrdm of the circuit an Fig. 3.11 shows the
waveform at each point.
a. The play signals from the play EQ amplifiers of the
left and right channels are amplified and mixed by
Q606 and Q626.
b. The mixed signal is further amplified by Q503 via
the sensitivity adjuster and the high-pass filter.
c. The high-pass filter turns on and off Q502 to change
the cut-off frequency.
In the CUE/REVIEW mode, the tape runs faster than
in the PLAY mode and the play frequency band is
shifted up so Q502 turns on. The cut-off frequency
of the high-pass filter is shifted up by inserting R506
in parallel with R505.
When the tape runs at a high speed as in the CUE/
REVIEW
Mode,
the
play
signal
level
is
increased.
This signal is controlled when R506 is grounded by
Q502 and the circuit impedance is reduced.
d. The output signal from Q503 is fed to limiter-1 con-
sisting of Q551 and 0552 to limit the meximum
amplitude to about 0.6V.
e.
The
output
of
limiter-1
is
amplified
by
Q504
and
is
fed to limiter-2 consisting of Q553—Q556.
Amplifier
Q504
and
limiter-2
amplify
lon
level
signals
whose
amplitude
was
not
limited
by
linniter-1,
When
the
signal
is
limited,
the
play
signal
is
«hanged
to
a
pulse
signal.
The
amplitude
of
the
output
signal
of limiter-2 isOV + 0.2V.

. This signal is amplified by O505 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 OV, to the positive side without changing
its amplitude.
. The DC shifted signal pulses pass through emitter
follower Q506 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
C503 is about 0.63V. 0508 and 0509 in the Schmitt
circuit are ON and OFF, respectively; Q501 is ON
while Q509 is OFF. Pin 35 of the microcomputer is
at low level.
i. When left and right channel play signals are not pre-
sent, the pulses charging C503 stop so C503 dis-
charges into the Schmitt circuit via R523.
When the potential of C503 drops to about 0.55V,
the Schmitt circuit is inverted and Q501 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 C513 through R525 and Q507 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 levei can be adjusted with R615.
15

4. Tape Operation
During
programming
operation,
the
mode
of
tape
opera-
tion cannot be selected with the pushbuttons.
The
following
describes
the
functions
of
pushbuttons
and
related
circuits.
Unless
it
is
stated
otherwise,
the
deck
is
in
the
STOP
mode
before
any
pushbuttons
are
pressed.
4.1 PLAY mode
With
the
PLAY
button
pressed,
circuit
Q701
in
the
microcomputer
is
set
to
the
PLAY
mode
and
a
high
level
PLAY
signal
is
output
from
pin
31.
This
signal
passes
through 0572, R553 and R554 to turn on Q516.
At
this
time,
Q517
is
OFF
and
the
signal
at
the
collector
is
inverted
from
low
to
high
level
and
the
following
Operations are performed.
(1)
0528
is
switched
ON
via
R557,
R536
and
0536
and
the
amplifier
is
set
to
the
PLAY
mode
(see
Fig.
4.1)
as
follows.
Fig. 4-1 Muting control circuit
PKI
—— =.
A
P400 wax eeegeoee
—
aang)
402 6, . G i
ae ea 29 3429 6430 Se se Si8gt? BS 2209
=
CHO
aeaen
Pore
ba
39
”
“hiss
~
-
z
‘age
.~
To
the
sao
tase
Oe
ef
"="
recording
eaten
fren
‘
QO
output
wf
hae
pm
+8.6V|
2K.
rou
Amplifier
bra
i
Rees
mnt
ere
®)
Os
Pa
ara | Rass Kk ) 642) ~ + +
| AQ oor “2
arias
Meyg2
26
nena
PK22
Taye
ST,
Ph
-
Power
Supply
ye ne
neo LED METER
a.
0643
is
switched
OFF
and
the
voltage
regulator
cir-
cuit operates to supply power to the LED meter.
b.
Q109
and
Q209
are
switched
OFF
to
release
the
mut-
ing function of the play output circuit.
c,
Q111
and
Q211
are
switched
OFF
to
release
the
mut-
ing function of the recording output circuit.
(2)
Q534
is
switched
ON
for
about
0.5
sec
via
R557,
C515
and
Q569.
In
the
circuits
following
Q534,
the
solenoid
drive
voltage
is
selected
as
discribed
previously
(Item
3.3).
(3)
Q523
and
Q527
are
switched
ON
via
R557,
Q568
and
R596.
The
brake
solenoid
LOO2
is
activated
to
release
the
braking
of
the
reel
disks.
(4)
Q522
and
Q529
are
switched
ON
via
R557
and
R563.
PLAY
LED
Q591
lights
and
play
solenoid
L001
is
activated
to
set
the
deck
in
the
PLAY
mode.
16
4.2 REC/PLAY mode
The
deck
cannot
be
set
to
the
REC/PLAY
mode
unless
ANTI-REC
switch
S002
is
open.
Also,
the
deck
cannot
be
set
to this
mode
manually
unless
PROGRAM
MODE
switch
$506
is
in
the
OFF/CA
position
and
COUNTER
MEMORY
switch
$504
is
in
the
OFF,
REWIND/STOP
or
REWIND
/REPLAY
position.
(1)
By
pressing
the
PLAY
and
REC
buttons
simultane-
ously,
a
high
level
play
signal
and
recording
signal
are
present
at
Pin
31
and
Pin
32
of
the
micro-
computer,
respectively.
The
deck
is
set
to
the
PLAY
mode
by
the
play
signal.
The recording signal functions as follows:
a. Q511 is switched ON via Q560, Q530 and R532.
Q512 is OFF and Q513 and 0525 are ON.
b. REC LED 0593 is lit by Q513.
c.
REC
solenoid
L004
is
activated
by
0525,
REC/PLAY
switches
S101
and
S102
in
the
amplifier
are
set
to
REC.
The
amplifier
is
set
to
the
recording
mode.
(2)
If,
during
the
PLAY
mode,
the
PLAY
and
REC
buttons
are
pressed
at
the
same
time,
the
deck
is
also
set
to
the
REC/PLAY
mode.
In this case, the following operations are performed,
as well as the operations given in a throughc.
d.
Q512
is
switched
OFF
and
the
signal
at
the
collector
become
high
level.
This
signal
passes
through
R535,
C514
and
Q563
to
activate
the
solenoid
drive
voltage
selector
circuit
following
Q534.
Thus,
the
voltage
of
the
REC
solenoid
is
switched.
(3)
With
REC/MUTE
switch
S502
pressed
during
the
REC/PLAY
mode,
the
recording
amplifier
is
muted
and
hence
the
recording
signal
goes
off.
At
this
time,
the
display
indicates
second’s
digits
auto-
matically
regardless
of
the
position
of
the
program
setting
switch.
The
display
indicates
0-9
seconds
repeatedly
while
S502
is
pressed.
As
explained
previously,
a
blank
space
of
more
than
3 :econds
is
required
for
proper
operation
of
the
program
de-
tection
circuit,
so
that
length
of
blank
tape
can
be
determined
by
the
time
indicated
during
the
REC/
MUTE
operation.

4.3 PAUSE mode
(1) PLAY/PAUSE
If the PAUSE button is pressed when the deck is in the
STOP, FF or REW mode, the PAUSE signal is not
output. By pressing the PAUSE button during the
PLAY mode, the PLAY signal (Pin 31 of the micro-
computer) becomes low level and the PAUSE signal
(Pin 31) becomes high level. With this, the tape is set
to the STOP mode and the amplifier is muted.
The high level PAUSE signal has the following functions:
a. Q524 is switched ON via R541 and the PAUSE LED
Q592 is lit.
b. Q515 is switched ON via 0575 and R558, discharging
C522.
c. Q526 is switched ON via R542 (0526 does not func-
tion at this time).
d. Q530 and Q531 are switched ON via R548, Q599 and
R692. CUE/REV solenoid LO04 is activated by
Q531 (in this case, the solenoid drive voltage selector
circuit does not operate). The CUE/REV solenoid
sets the head base between the STOP and PLAY
positions. When the PLAY button is pressed in the
PLAY/PAUSE mode, the PAUSE signal level becomes
low and the PLAY signal level becomes high.
The PAUSE signal goes off and then the PLAY signal
comes on about 25 msec later. CUE/REV solenoid
L003 is OFF and PLAY solenoid L001 is ON.
(2) REC/PAUSE
When the PAUSE button or the REC and PAUSE but-
tons are pressed in the REC/PLAY mode, the tape is set
to the REC/PAUSE mode. In either the REC/PLAY or
REC/PAUSE mode, the REC signal is output and the
amplifier is set to the recording mode. Other functions
are the same as in the PLAY/PAUSE mode.
4.4 FF mode
When the FF button is pressed, FF and FAST signals are
output from Pin 27 and Pin 26 of the microcomputer,
respectively.
The FF signal has the following functions:
a. Q549 is switched ON via R579. The slack tape re-
moval circuit stops operating when 0549 is ON.
b. The reel motor drive circuit is activated via R570.
The FAST signal has the following functions:
c. Q515 is switched ON via Q573 and R558 to disable
the PLAY signal circuit.
d. Q510 is switched ON VIA R531 to disable the REC
signal circuit.
e. Q534 is switched ON momentarily via R559, C516
and Q576 to operate the solenoid drive voltage
selector circuit.
f. Q523 and Q527 are switched ON via R559, Q571 and
R596 to operate BRAKE solenoid L002.
4.5 REW mode
When the REW button is pressed, the REW signal and
FAST
signal
are
output
from
Pin
28
and
Pin
26
of
the
microcomputer, respectively. The functions of these
signals are practically the same as in the FF mode.
17
4.6 STOP mode
In
any
of
the
following
cases,
the
deck
is
set
to
the
STOP
mode
during
any
mode
other
than
the
program
mode.
a. When the STOP button is pressed.
b.
When
the
SENSOR
STOP
switch
is
pressed.
c. When the tape reaches its end.
d.
When
PROGRAM
MODE
switch
S506
is
set
from
the
SINGLE
position
to
the
OFF/CA
position.
e.
When
the
COUNTER
MEMORY
switch
$504
is
set
from
the
PLAY/STOP
position
to
the
OFF
position
with
the
PROGRAM
MODE
switch
in
the
OFF/CA
position.
During
the
program
mode
operation,
the
SENSOR
STOP
switch
does
not
function.
When
unloading
the
cassette,
the
program
mode
operation
is
stopped
and
the
tape
deck
is
set
to
the
STOP
mode.
The
program
mode
Operation
stops
by
the
procedures
given
in
the
above
items d ane e.
4.7 Mode transfer
When
the
mode
of
operation
is
transferred
from
A
to
B,
the
signal
in
Q701
goes
off
and
then
the
B
signal
is
out-
put
on
about
25
to
30
msec
later.
The
tape
deck
is
in
the
STOP
mode
until
the
B
signal
is
output.
When
the
mode
of
operation
is
changed,
the.
tape
stops
once
and
then
starts
again.
4.8 Functions of operation buttons
When
more
than
one
operation
button
are
pressed,
the
priority
of
the
mode
is
determined
by
the
microcom-
puter.
Except
when
the
PLAY
and
PAUSE
buttons
are
pressed,
the
tape
mode
is
determined
by
the
button
which
is
released
last.
The
relationship
between
the
Operation
buttons
and
the
modes
of
operation
is
as
follows:
a. STOP button and any one of REW, FF, PLAY,
PAUSE and REC buttons... STOP mode.
b, REW button and FF button... STOP mode.
c. REW (or FF) button and any one of PLAY, PAUSE
and REC buttons... REW (or FF) mode.
d. PLAY button and PAUSE button
(1) When the PLAY button is pressed first .. . PLAY
mode (or the mode of the button released last).
(2) When the PAUSE button is pressed first .. . STOP
mode (STOP mode when the PLAY button is re-
leased
first,
and
PLAY
mode
when
the
PAUSE
button is released first).

5. Programming
Fig. 2.4 shows the program signal input circuit. The
switches in the matrix circuit, program memory and
control signal output are controlled by the micro-
computer.
This section explains the operating conditions of the
program setting switches and related functions.
The program setting switches have various functions, so
special care should be taken when checking for circuit
trouble or misoperation.
5.1 Matrix keys
Here, the functions of the program setting matrix keys
are explained. For the functions of the 3 switches
(COUNTER MEMORY, SELECTOR, PROGRAM
MODE) at the lower part of the program setting unit,
refer to Section 5-2 and succeeding sections.
Fig.5-1 Program setting unit
Ba SELECT
°
i a a
START SKIP PAT PM RAM SAM
° fe) °
Oooo
START STOP MEMORY ON OFF
“ COUNTER CALL & TIMER ~
ge ee re
FOIE
CE/RESET
SINSLE a
COUNTER, . CLOCK RE-
a AY () AT] TIMER cieek PEAT® ‘on
| “©. : . ‘o” ‘u)
Fino PLAY
COUNTER MEMORY SELECTOR PROGRAM MODE
(1) START
This is a program mode start command key.
When the PROGRAM MODE switch is in the SINGLE
or REPEAT position and the COUNTER MEMORY
switch is in the PLAY/STOP or PLAY/REPEAT posi-
tion, press the START key and the deck is set to the
REW mode regardless of the position of the SELECTOR
switch and the information stored in the memory.
(2) SKIP
This key is used to shift from one program to another
during program mode operation.
When the PROGRAM MODE switch is in the SINGLE
position and the last designated program is being played
back, pressing the SKIP key causes the tape deck to
enter the STOP mode.
(3) PRG PAUSE
This is the PROGRAM PAUSE key. Press this key dur-
ing the program mode operation and the tape stops
briefly. To resume tape playback, press the same key
again.
18
(4) PM
This key is used to indicate the PM (afternoon) sign on
the display. It functions only when the SELECTOR
switch is in the CLOCK SET position. By pressing the
PM key, the display indicates as shown in Fig. 5.2.
Fig. 5-2 Indication when PM key is pressed
4° ry
re 2.0
(5) RAM, SAM
These are RANDOM ACCESS MEMORY key and
SEQUENTIAL ACCESS MEMORY key, and are used
for memorizing, executing and reading programs.
When the RAM key is used, the programs are executed
in the order in which they are arranged. When the SAM
key is used, the programs are executed in numerical
order. !f the programs are arranged in the order of 4, 5,
3, 2 and 1, they are executed (readout) by the memory
as shown in Table below.
Read-in i Read-out, Execution |
| Mode Sequence | Mode Sequence |
t t
| : RAM|4—5-3-2-1
/RAM/4-5-3-2-1. to"
| SAM | 1 Pe 94e'5
; RAM|4—5—-3-2—1
sam |4—5—-3-2-118 ul areca a
'SAM/1—2-3-4-5
The LEDs on the RAM and SAM keys indicate the
memory being executed. They will tight with the PRO-
GRAM MODE switch
position.
in the SINGLE or REPEAT
(6) COUNTER/START, STOP
This is used to set the start and stop positions for
counter, memory and play operations (STOP, REPEAT).