JVC DD-9 A User manual
MODEL
DD-9
A/B/C/E/J/U
STEREO
CASSETTE
DECK
No.
4198
March
1981
DD-9A/B/C/E/J/U
|
Contents
Page
Features
sy
hn
ge
west
OEE
end
ES
ena
nad
we
alee
%
2
Specifications:
~f
sadeiaclha
woe
aeons
ba
eee
es
3
Controls
and
Connections
...........2
002
ee
eee
4
Main
Parts
Location
........-..
00000
eee
eee
5
Maintenance
.....
2.0...
0.
eee
ee
ee
eee
5
Description
on
New
Technology
..............0-
6
Removal
of
the
Main
Parts
................0005
8
Main
Adjustments.
.........0
0.000
ee ee ee
eee
9
Block
Diagram
(1)
2.0.0.0...
2.
cee
eee
ee
eee
17
Block
Diagram
(2)
1...
0...
ee
es
18
Wiring
Connection
(1)
..............2222000-
19
Wiring
Connection
(2)
.............0000
tees
20
Wiring
Connection
(3)...
0.2.0.0...
0
eee
ee
eee
21
Standard
Voltage
Value
............0000
eee
22
Integrant
Circuits...
ee
ee
ee
23
Standard
Schematic
Diagram
(Main
Amp.
Circuit)
...
25
Standard
Schametic
Diagram
(Computer
Circuit)
....
26
Standard
Schematic
Diagram
(Mecha.
Control
Circuit).
27
Features
=
2-motor
full-logic
mechanism
with
quartz-locked
pulse-
servo
D.D.
motor
©
A
quartz-locked
pulse-servo
D.D.
motor
newly
developed
for
capstan
drive
and
a
DC
motor
for
reel
drive
©
Low
wow/flutter
(WRMS
0.019%)
©
TIMER
STANDBY
mechanism
(with
maloperation
protection)
©
AUTO-REWIND
mechanism
©
Remote
control
terminal
provided
(R-50E
optional)
@
Built-in
computer
B.E.S.T.
tuning
system
for
automatic
adjustment
of
Bias,
Equalization
and
Sensitivity
of
tape
=
Metal
tape
compatible
®
Three-head
system
permitting
monitoring
while
record-
ing
is
being
made
©
X-cut
SA
(Sen-Alloy)
combination
record/playback
head
©
2-gap
SA
erase
head
No.
4198
Page
Standard
Schematic
Diagram
(Fl
Circuit,
DD
Motor
Circuit)
..........00.0.
28
Enclosure
Assembly
and
Electrical
Parts
..........
29
Mechanical
Component
Parts
............2200%
30
Enclosure
Assembly
and
Electrical
Parts
List
.......
31
Mechanical
Component
Parts
List
..............
34
Main
Amp.
P.W.
Board
Parts
List...............
36
Main
Amp.
P.W.
Board
Parts.
...........000005
39
Computer
P.W.
Board
Parts
..........-..00005
40
Computer
P.W.
Board
Parts
List
...............
41
Mecha.
Control
P.W.
Board
Parts,
Parts
List........
44
Display
P.W.
Board
Parts,
Parts
List
.............
46
DD
Motor
Circuit
Parts
List
............
2.00004
47
Other
P.W.
Board
Parts
...
0.0...
0000
eee
eee
48
Other
P.W.
Board
Parts
List
..............200.
49
Packing,
Packing
Material
Parts
List
........
Back
cover
ACCESSOFIES:
eh
-8
5S
5,
Be
RES
eS
Back
cover
®
2-color
FL
digital
meter
(PEAK/VU
selectable)
with
peak
hold
function
®
DC
configured
record/playback
amplifier
™
Electronic
control
for
recording
level
adjustment
=
Equipped
with
ANRS/DOLBY
B
and
DOLBY
C
NR
moise
reduction
systems.
@
Timer
standby
capability
for
automatic
recording
or
playback
using
an
AC
timer
®
Headphones
in
connection
with
slide
system
output
level
control
m
Record
muting
(REC
MUTE)
mechanism
(with
operation
indicator
LED)
®
New
slim
design
with
push
button
switches
Specifications
Type
:
Component
stereo
cassette
deck
Track
system
:
4-track,
2-channel
Tape
speed
:
1-7/8
inch/sec
(4.8
cm/sec)
Frequency
response
:
(—20
VU
recording)
Metal
tape
o4
;
15—20,000
Hz
25—18,000
Hz
(+
3
dB)
SA/Chrome
tape*2;
15—20,000
Hz
25—18,000
Hz
(+
3
dB)
SF/Normal
tape
*3;
15—19,000
Hz
(0
VU
recording)
Metal
tape
SA/Chrome
tape
SF/Normal
tape
25—17,000
Hz
(+
3
dB)
;
25—12,500
Hz
(+
3
dB)
;
25—8,000
Hz
(+
3
dB)
;
25—8,000
Hz
(+
3
dB)
Frequency
response
when
using
the
computer
B.E.S.T.
tuning
system:
(—20
VU
recording)
Metal
tape
SA/Chrome
tape
SF/Normal
tape
Note:
“1
;
40—12,500
Hz
(+
1
dB)
;
40—12,500
Hz
(+
1
dB)
;
40—12,500
Hz
(+
1
dB)
Those
values
are
almost
the
same
for
all
types
of
tapes
when
the
com-
puter
B.E.S.T.
tuning
system
is
used.
JVC
ME
or
Equivalent
*2
.....
TDK
SA
or
Equivalent
Lic
ea
S/N
ratio
NR
effect
Wow
and
flutter
Crosstalk
Harmonic
distortion:
MAXELL
UD
or
Equivalent
;
60
dB
(DIN
45
500
weighted,
Metal
tape)
;
5
dB
at
1
kHz,
10
dB
at
5
Cae
{lANRS/Dolby
B
NR)
15
dB
at
500
Hz
20
dB
at
1
kHz
_f
(Dolby
©
NR)
:
0.019%
(WRMS)
with
JVC
test
tape
0.055%
(DIN
45500)
with
MAXELL
UD
tape
:
65
dB
(1
kHz)
K3;
0.4%,
THD;
1.0%
(Metal
tape,
1
kHz,
0
VU)
Bias
Erasure
Heads
Motors
Fast
forward
time
Rewind
time
Semiconductors
Input
terminals
Mic
jack
x
2
Input
jack
x
2
Output
terminals
Output
jack
x
2
Phone
jack
x
1
DD-9A/B/C/E/J/U
:
AC
bias
:
AC
erasure
:
3
heads
SEN
ALLOY
head
for
recording,
SEN
ALLOY
X-cut
type
for
play-
back
and
two-gap
SEN
ALLOY
head
for
erasure
:
Quartz-lock
pulse
servo
DD
motor
(for
Capstan)
DC
motor
(for
Reel}
:
85
sec
or
less
with
C-60
cassette
:
85
sec
or
less
with
C-60
cassette
:
45
ICs,
140
transistors,
88
diodes,
2
hall
(C,
18
LEDs
Max.
sensitivity;
0.2
mV
(—72
dBs)
Matching
impedance;
600
§2~
10
kQ2
Min.
input
level;
80
mV
(—20
dBs)
Input
impedance;
100
k{2
;
Output
level;
O
~
500
mV
Output
impedance;
5
kQ2
;
Output
level;
O
~
0.6
mW/8
G2
Matching
impedance;
8
Q)
~
1
kQ
Remote
control
socket:
8
pin
DIN
type
(for
R-50E
optional)
Power
requirement
Power
consumption
Dimensions
Weight
:
AC
240
V,
50
Hz
(DD-9A)
AC
120
V,
50
Hz
(DD-9C/J)
AC
240/220/120
V,
50/60
Hz
(DD-9B/E)
AC
240/220/120/100
V,
50/60
Hz
(DD-9U)
>
40
W
>
17-3/4"
(450
mm)
W
12-3/4"
(325
mm)
D
4-3/8”
(110
mm)
H
(with
feet,
buttons,
switches)
:
18.5
Ibs
(8.4
kg)
Design
and
specifications
subject
to
change
without
notice.
No.
4198
DD-9A/B/C/E/J/U
Controls
and
Connections
aa
ie
$e
Fig.
1
30
e
VOLTAGE
SELECT
nfs
REMOTE
CONTROL
—
ROWER
SOURCE
(
m
UOLRY
AND
ONE
DOUBLED
SUMBOL
ARI
TRADEMARKS
GF
DALEY
At
RATORI'S
ca
2
Ainianantenintinmmanntr
eT
itferntmeenttnntin
te
33
Fig.
2
1.
POWER
switch
2.
TIMER
STANDBY
switch
3.
FL
meter
4.
COMPUTER
B.E.S.T.
TUNING
SYSTEM
indicators
5.
DOLBY
B/ANRS
and
DOLBY
C
indicators
6.
TAPE
(METAL)
indicator
7.
MONITOR
(SOURCE,
TAPE)
indicator
8.
PRESET
indicator
9.
ERROR
indicator
10.
Cassette
holder
11.
Electronic
counter/Reset
button
12.
Quartz
lock
indicator
13.
AUTO
REWIND
switches
14.
OUTPUT
LEVEL
knob
15.
PHONES
jack
(Headphone)
16.
MIC
jacks
(Microphone)
17.
NRswitches
18.
TAPE
SELECT
switches
19.
COMPUTER
START
button
20.
COMPUTER
PRESET
button
21.
MONITOR
button
No.
4198
19
20
21
22
23
24
31
ereouENEY
©)
J
25
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
25
26
27
28
WANUFACTURED
8Y
3)
CTOR
CoMPamy
OF
IAPLN
LTH
FORTO
APRN
AD]
IN
PAN,
en
METER
switch
(VU
@
PEAK)
INPUT
BALANCE
knob
INPUT
LEVEL
buttons
(DOWN
«
UP)
EJECT
button
COUNTER/STOP
WATCH
select
switch
MEMORY
switch
REC
MUTE
button
Cassette
operation
buttons
<<)
REW
(Rewind)
button
with
indicator
>
PLAY
button
with
indicator
>>
FF
(fast-forward)
button
with
indicator
fe)
REC
(Recording)
button
with
indicator
.
STOP
button
|
PAUSE
button
with
indicator
REMOTE
CONTROL
socket
FREQUENCY
select
switch
(50
Hz/60
Hz)
MPX
filter
switch
Voltage
select
switch
(DD-9B/E/U)
LINE
IN
(REC)
terminals
LINE
OUT
(PLAY)
terminals
Power
cord
|
i
Main
Parts
Location
Maintenance
To
get
long,
trouble-free
service,
maintenance
is
important.
Do
not
forget
cleaning
and
demagnetizing.
Cleaning
After
long
use,
the
heads
and
tape
part
—
capstan,
pinch
roller,
etc.
—
will
become
dirty
with
dust
or
magnetic
particles.
Dirty
heads
cause
imperfect
erasing
or
high
fre-
quency
drop-off.
A
dirty
capstan
and
pinch
roller
will
cause
unstable
tape
speed,
leading
to
increased
wow
and
flutter.
Always
keep
them
clean
by
following
the
procedure
below.
1.
Heads
1)
Push
Eject
button
to
open
the
cassette
holder.
2)
Use
the
head
cleaning
stick
provided
to
wipe
the
surface
where
the
tape
comes
into
contact
with
the
head.
(It
is
effective
to
moisten
the
cotton
with
alcohol.)
2.
Pinch
roller
and
capstan
Do
the
samemethod
as
heads.
3.
Cabinet
When
the
cabinet
becomes
dirty,
wipe
it
with
a
soft
cloth
soaked
with
a
neutral
cleaning
solution
of
a
polishing
cloth.
*
Do
not
use
thinner
or
benzine.
|
DD-9A/B/C/E/J/U
Power
switch
Pin
jack
ass‘y
Computer
P.W.B.
ass’y
Power
supply
P.W.B.
ass’y
Power
transformer
Front
plate
ass’y
F.L.
P.W.B.
ass’y
Gear-oiled
damper
Mechanical
assembly
Mecha.
control
P.W.B.
ass’y
Auto
stop
pulley
POSEN
OAPWN
>
_—
—
Mechanical
parts
are
the
same
as
location
of
model
DD-7,
Please
refer
to
the
service
manual
of
DD-7A/B/C/E/J/U
(No.
4195
—
page
3).
Demagnetizing
The
heads
are
made
from
a
material
resistant
to
magneti-
zation,
but
after
long
use
they
may
become
magnetized.
A
magnet
brought
into
their
vicinity
can
magnetize
the
heads,
causing
excess
noise.
If
noise
seems
to
have
increased,
demagnetize
the
heads
with
a
head
demagnetizer
through
the
following
procedure.
1.
Turn
the
POWER
switch
OFF.
2.
Wrap
the
tip
of
the
demagnetizer
with
vinyl
tape
or
soft
cloth
so
as
not
to
damage
the
head
surface.
Switch
on
the
demagnetizer
and
bring
it
close
to
the
head.
3.
Move
the
tip
of
the
demagnetizer
slowly
first
to
the
left
and
right,
then
up
and
down
in
front
of
the
head.
Gradually
move
it
away
from
the
head
and
switch
it
off
at
a
distance
of
more
than
30
cm
(12”).
4.
The
erase
head
need
not
be
demagnetized.
The
capstan
shaft
and
tape
guide
should
be
demagnetized
in
the
same
way
as
the
record/playback
head.
Do
not
bring
a
magnetized
metallic
object
(a
screwdriver,
for
example)
near
the
head
as
this
will
increase
noise.
No.
4198
|
|
:
DD-9A/B/C/E/J/U
|
Description
on
New
Technology
=
DD
(Direct
Drive)
Mechanism
Equipped
with
Newly
=
Memory
Stop
and
Auto-rewind
Developed
Quartz-locked
Pulse
Servo
DD
Motor
A
direct
drive
system
is
employed
in
which
the
motor
shaft
itself
is
the
capstan
shaft,
without
the
rotation
transmitting
members
(idlers,
pulleys,
etc.)
which
cause
unstable
tape
rotation.
Our
newly
developed
pulse
servo
motor
is
employed
for
this
driving
power
source.
The
motor’s
construction
is
free
from
thrust
unbalance
or
cogging,
thus
permitting
a
high
flywheel
effect.
For
precise
rotation,
this
motor
uses
a
full-circumference
integration
type
FG
detection
system
and
an
auto-
balance
circuit
which
reduces
torque
unbalance.
Thus,
the
motor
drives
the
tape
transport
mechanism
with
smooth
rotation.
Further,
the
employment
of
the
quartz
lock
system
results
in
exceedingly
small
fluctuation
of
speed.
For
detailed
information,
refer
to
service
manual
(No.
4195)for
DD-7.
Three-head
System
with
X-cut
SA
Record/Playback
Combination
Head
The
record
head
uses
a
4u-gap
SA
head
for
improved
recording
sensitivity
and
a
reduced
distortion
rate.
The
playback
head
uses
an
X-cut
1p-gap
SA
head
for
reduced
low-frequency
contour
effect.
These
two
heads
are
com-
bined.
The
erase
head
employs
a
2-gap
SA
head
excellent
in
erasure
efficiency.
For
more
details,
refer
to
page
5
in
service
manual
(No.
4186)
for
KD-A77.
All-stage
DC
Configurated
Amplifiers
The
playback
head
and
the
equalizer
amplifier
are
direct-
ly
coupled.
Since
all
stages
between
amplifiers
are
DC
configured,
the
number
of
the
capacitors
which
adversely
affect
sound
quality,
is
decreased.
In
addition,
the
+2
V
constant
voltage
source
and
the
differential
amplifier
enable
stable
high
linearity
and
wide-band
reproduction.
Dot-matrix
Type
2-color
FL
(fluorescent
tube)
Peak
Level
Meter
The
2-color
fluorescent
indicator
tube
which
is
longest
at
135
mm
among
cassette
decks.
The
R
and
L
indicator
bars
are
independent
of
each
other.
Each
bar
is
divided
into
18
segments,
each
further
into
20
dots.
So,
the
level
can
be
monitored
with
a
feeling
of
a
consecutive
bar
graph.
This
meter
is
provided
with
a
peak-hold
function,
thus
facilitating
level
setting.
Moreover,
it
has
a
selection
switch
between
the
PEAK
and
VU
meters.
No.
4198
By
joint
use
of
the
MEMORY
switch,
AUTO
REWIND
switch
(PLAY/STOP)
and
the
electronic
counter,
the
following
operations
are
possible:
Continuous
tune
repeat
between
the
beginning
of
the
tape
and
the
point
of
the
tape
at
which
the
MEMORY
switch
is
pressed;
tune
repeat
between
‘000’
to
which
the
counter
is
reset
by
the
RESET
switch
and
the
point
of
the
tape
at
which
the
MEMORY
switch
is
pressed
or
between
this
pcint
of
the
tape
and
the
end
of
the
tape.
Needless
to
say,
the
conventional
functions
can
be
per-
formed
by
ON-OFF
operation
of
the
MEMORY
switch
or
the
AUTO-REWIND
switch
(ON/OFF)
singly.
Electronic
Volume
Control
Motor
rotation
is
controlled
by
switching
the
polarity
by
IC
so
that
the
input
volume
can
be
set
by
one-touch
recording
level
UP-DOWN
operation.
The
set
recording
tevel
is
indicated
by
the
needle
which
moves
in
response
to
the
control
motor.
Newly
Developed
Computer
B.E.S.T.
(Bias
Equalizer
Sensitivity
Tuning)
System
3-head
Tape
Deck
This
system
was
developed
for
3-head
tape
deck
utilliz-
ing
the
fundamental
concept
of
the
previous
versions
KD-A8
and
KD-A66.
With
stress
laid
upon
MOL
balance,
the
bias
leve!
is
set
at
the
average
of
the
optimum
bias
points
which
are
detected
at
16
steps
each
for
R
and
L
channels.
To
control
the
medium-frequency
response,
a
process
to
make
the
4
kHz/1
kHz
response
flat
is
provided.
This
response
is
set
at
the
average
between
those
R
and
L
values
which
are
taken
each
at
8
steps.
The
tape
sensitivity
is
set
at
an
average
of
those
R
and
L
values
which
are
taken
at
16
steps
each.
The
high-
frequency
equalization
level
is
adjusted
at
16
steps
each
for
R
and
L
channels,
independently.
In
addition,
since
the
A/D
conversion
system
of
the
detection
signal
has
been
changed
from
the
peak-hold
type
to
the
soft
peak-hold
type,
a
momentary
pulse
due
to
noise
is
not
detected.
Therefore,
this
system
is
designed
to
hold
nothing
but
continuous
sigrals.
Dolby*
C-Type
Noise
Reduction
System:
Noise
is
reduced
and
MOL
increased
dramatically.
The
Dolby
C-type
closely
resembles
the
B-type
in
operation,
the
system
compatible
with
ANRS,
yet
offers
even
better
performance
and
more
distinctive
features.
Namely:
®
\|t
provides
about
20
dB
above
1
kHz,
and
15
dB
even
at
500
Hz
of
noise
reduction.
®
At
10
kHz
(at
OVU
recording),
it
improves
MOL
by
4
dB
maximum.
®
It
is
immune
to
undesirable
side
effects,
such
as
modu-
lation
noise
and
breathing.
®
Finally,
it
is
tolerant
of
noise
reduction
encode/decode
errors.
Level
matching
is
not
critical.
(*
Dolby
is
a
trademark
of
Dolby
Laboratories,
Inc.)
The
basis
of
C-type
noise
reduction
Dolby
C
noise
reduction
solves
the
problem
of
achieving
a
large
amount
of
compression
and
expansion
without
introducing
undesirable
side
effects
by
the
use
of
two
pro-
cessing
stages
in
series,
each
supplying
10
dB
of
compression
during
recording
and
of
expansion
during
playback.
These
circuits
operate
at
independent
levels.
One,
identified
as
the
high-level
stage
in
Figure
B,
is
sensitive
to
signals
at
about
the
same
levels
as
Dolby
B-type
noise
reduction,
while
the
other,
the
low-level
stage,
operates
on
signals
of
somewhat
lower
level.
Because
the
two
stages
operate
in
tandem
with
each
other,
their
effect
is
to
multiply
the
signals
(or
add
and
subtract
in
dB’s),
so
that
a
total
of
20
dB
of
compression
and
expansion,
and
thus
of
noise
reduction,
is
accomplished.
Yet
simultaneously,
at
no
time
is
the
signal
subject
to
the
vagaries
of
a
single
compression
or
expansion
action
of
20
dB.
In
other
words,
the
tandem
two-level,
two-stage
con-
figuration
provides
a
much
more
accurate
control
of
the
signal
than
a
single
compander
circuit
would
be
able
to
achieve.
Two
conventional
Dolby
B
IC
circuits
are
used
ina
modified
way
in
C-type
noise
reduction
to
carry
out
the
two-level,
two-stage
scheme.
Thus
a
desirable
side
benefit
of
C-type
noise
reduction
is
that
it
can
be
executed
from
the
begin-
ning
with
readily
available
and
economical
parts
(the
development
of
a
dedicated
Dolby
C
integrated
circuit
in
the
future
would,
however,
simplify
incorporating
C-type
NR
in
products).
Furthermore,
one
of
the
two
stages
can
be
easily
configured
to
provide
the
B-type
characteristic
at
the
push
of
a
switch,
so
cassette
decks
incorporating
C-type
noise
reduction
can
be
economically
equipped
with
Dolby
B
NR
as
well
for
perfect
compatibility
with
existing
B-type
recordings.
a
eae
ee
et
:
MOL
Improved
by
3
Reference
Level
(160nwb/m)
——-+=
about
4dB
(10kHz)
SEP
apo
pe
tots
Dolby*C
ON
=P“
Noise
Reduction
OFF
4-
:
i
PSE
SS ee
eg
ON
Kei
=
S/N
Improved
by
about
20dB=--}—
_-
(ikHz
and
above)
=
Eieaehattwalis
i
Output
Level
(dB)
BAS
reenrears
TARe
FSI
ARS
Noise
Reduction
OFF
Hi
Tay
eae
saith
ae
+)
ANRS/Dolby*B
ON
i
edt
t
I
se
|
SIN
Improved!”
{
{Dolby*c
ONT
E
“--H
by
about
15dB
5
-
20
50
100
200
500
1000
2000
5000
10000
20000
Frequency
(Hz)
Dolby*
C
Improvement
Other
developments
In
addition
to
two-level
processing,
Dolby
C-type
noise
reduction
incorporates
a
number
of
further
innovations.
Two
of
these,
shown
in
Figure
B
as
anti-saturation
and
spectral
skewing
networks,
are
carefully
calculated
fre-
quency
response
modifications
introduced
in
the
encoding
(record)
process
and
reciprocally
compensated
for
in
the
decode
(playback)
process.
Their
purpose
is
two-fold:
to
further
guard
against
audible
side
effects,
and
to
ensure
the
practicality
of
the
system
in
day-to-day
consumer
use.
The
specific
benefits
of
these
innovations
include
the
reduction
of
encode-decode
errors
and
a
reduction
of
upper-middle
and
high
frequency
tape
saturation
and
its
side
effects,
such
as
high
frequency
losses
and
_
inter-
modulation
distortion.
Together
with
the
two-level,
two-
stage
configuration,
these
new
developments
result
in
a
20
dB
noise
reduction
system
at
least
as
free
of
side
effects
as
the
10
dB
B-type
system,
and
one
which
is
just
as
practi-
cal
in
day-to-day
use.
—~6-A—
Tee
TTT
TTT
ce
TTT
BATT
HTT
LTT
CHAE
a
TTT
Fig.
A
Low-level
encoding
frequency
response
The
effect
also
extends
about
two
octaves
lower
with
C-
These
curves,
showing
the
maximum
low-level
boost
im-
parted
by
both
C-type
and
B-type
noise
reduction
in
the
type
noise
reduction
to
maintain
subjectively
uniform
noise
level
across
the
spectrum.
Processing
at
very
low
frequencies
absence
of
high
frequency
signals,
illustrate
some
of
the
is
not
required
with
either
system
because
low
frequency
noise
similarities
and
differences
between
the
two
systems.
Dolby
C
noise
reduction
imparts
more
boost
in
recording
and
more
cut
in
playback,
thus
providing
more
noise
reduction.
in
properly
engineered
cassette
insignificant
is
recorders.
TO
RECORDING
AMPLIFIER
IC2
SIDE*CHAIN
OF
LOW:
LEVEL
STAGE
4
|
J
|
|
|
A
Se
ee
---
|
L
DOLBY
C-TYPE
ENCODER
ANTI-
SATURATION
NETWORK
HIGH
*LEVEL
STAGE
SIDE-CHAIN
OF
ae
SPECTRAL
SKEWING
FROM
INPUT
STAGES
KB
i)
a
—
=)
oO
SPECTRAL
SKEWING
4
|
STAGE
SIDE+
CHAIN
OF
HIGH?
LEVEL
eles
SATURATION!
NETWORK
5
|
SIDE+
CHAIN
OF
LOW-LEVEL
STAGE
ae
x<
oc
Sui
aa
ter
par
gay
as
xt
oy
fe
DOLBY
C-TYPE
DECODER
Dolby
C-type
NR
block
diagram
Fig.
B
—6-B—
DD-9A/B/C/E/J/U
Features
of
New
B.E.S.T.
System
ee,
®
Bias
Level
Setting
System
with
MOL
Balance
Taken
into
=
Comparison
Table
between
KD-A66
and
DD-9
Consideration
cree
With
an
8
kHz
variable
normal
or
chrome
tape,
the
dif-
pia
pee
ference
in
bias
level
between
MML
(333
Hz)
and
MOL
eae
Bias
level
(B)
Coincident
point
of
7
kHz
and
1
kHz
The
bias
level
is
lowered
by
A
dB
due
to
the
(10
kHz)
is
set
to
12
dB,
while
with
a
metal
tape,
it
is
set
(2)
8
steps
bias
current
characteristics,
as
the
MOL
bal-
to
around
8
dB.
The
MOL
balance
is
thereby
stabilized.
penne
||
Detection
at
R
channel
ance
is
considered.
4
a
peak
point?
eee
:
Wes
16
steps
=
High-accuracy
Bias,
Equalization
and
Sensitivity
Level
—
Average
value
between
R
and
L
channels
Is
there
the
Setting
System
set
bias
point?
eae
:
Se
;
a
Medium-frequency
Coincident
point
of
4
kHz
and
1
kHz
2
Rh
ee
The
accuracies
of
bias,
sensitivity,
medium
and
high
fre-
quency
equalization
levels
are
greatly
improved
through
average
calculation
of
reading
error.
8
steps
Average
value
between
R
and
L
channels
Coincident
point
of
12.5
kHz
and
1
kHz](1)
Coincident
point
of
12.5
kHz
and
1
kHz
(2)
8
steps
(2)
16
steps
Detection
at
R
and
L
channels
Recording
is
performed
3
times
at
each
step.
(3)
Average
value
between
R
and
L
channels
Equalization
level
{medium
frequency)
adjustment
equalization
level
(EQ
M)
FIRST
BIAS
ds
the
response
at
1
kHz/4
kHz
flat?
NO.
High-frequency
equalization
level
(EQ
H)
=
Second
Bias
System
Recording/playback
With
a
special
tape,
the
respective
levels
are
readjusted
sensitivity
adjustment
by
this
system,
thus
their
accuracies
are
assured.
(1)
(1)
Coincident
point
of
recording
and
playback
at
1
kHz
(2)
16
steps
(3)
Average
value
between
R
and
L
channels
Coincident
point
of
recording
and
playback
at
1
kHz
(2)
8steps
(3)
Detection
at
R
channel
About
25
sec
Tape
sensitivity
level
(S)
Are
the
recording
and
playback
sensitivities
equal
with
each
other?
NO
=
4-bit
1-chip
2k
ROM
Microcomputer
Equalization
level
(high
frequency)
adjustment
Required
time
About
30
sec
(This
time
differs
slightly
according
to
the
tape
used.)
4-bit
1-chip
2k
ROM
4-bit
1-chip
2k
ROM
1s
the
response
at
1
kH2/12.5
kHz
flat
NO
Set
B.E.S.T.
j
]
a
Indications
PRESET/ERROR,
RUN/READY
B,
EQM,
S.EQH,
PRESET,
ERROR
Memory
Not
provided
Temporary
memory
1s
the
response
NO
.
atl
HL
2:
RHE
te
a
A/D
conversion
Peak-hold
type
Soft
peak-hold
type
4
Equalization
level
(medium
frequency)
adjustment
Grant
Bias
level
setting
Bias
level
setting
L
channel
7
EHO
LHe
INO
—
‘
channel
at
;
oS
Zz
BkH2
ne
lat?
oi
'
a
nil
|
fe
Recording/playback
sensitivity
MOL
balance
nas
aie
T
aa
;
;
|
adjustment
‘ '
. .
.
|
|
|
Phy
ae
non
ips
2
With
the
linearity
characteristics
of
the
tape
and
the
fre-
|
MOL
difference
annEaI
BESIABOLEEE
cea
rl
ty
a
:
r .
ot
eye
a
¢
quency
components
of
the
input
signals
taken
into
con-
REC
ON
ias
level
detectin
i
Are
the
i
‘ :
R
channel
Bias
level
detecting
point
L
channel
Bias
level
detecting
point
8
Fecording
and
playback.
No
=
sideration
to
record
musical
signals
at
good
balance,
the
315
Hz
10
kHz
”n
«
|
Spon
emnert
difference
between
the
low-frequency
(315
Hz,
K3
:
3%)
i
MOL
and
high-frequency
(10
kHz)
saturation
MOL
(or
Medien
frequency,
eqilalization
Tape
sensitivity
level
setting
i
.
:
3s
id
(
)
{
lel
setting
Equalization
Jevel
(high
SOL)
is
set
to
12
dB
on
normal
tapes
and
8
dB
on
high-
|
frequency)
adjustment
\
performance
tapes
such
as
metal
tapes,
etc.
Output
es
Lg
ee
sinned
ina
ico
Thus,
the
maximum
recording
level
is
determined
and
& 6
(ket,
T
1
kHz/12.5
a
i j
i
i
{hie
cial
le
nll
cele
ul
|
allele
fiat?
2
oe
the
bias
current
is
set
with
a
MOL
difference.
A
dB
;
SS
Ce
eee
eas
sae
4
feieorer
Practically,
a
signal
of
8
kHz
is
recorded
based
upon
the
I
Medium-frequency
equalization’?
(Reference
level}
Tape
sensitivity
level
Set
B.E.S.T.
?
; : ,
level
detecting
point
detecting
point
data
of
various
tapes
and
the
MOL
balance
is
determined
8
kHz
j
é
na
NA
!
by
the
bias
current
characteristics
for
this
signal.
Bias
current
I
:
\
High-frequency
equalization
level
setting
High-frequency
equalization
level
setting
R
chinnel
L
channet
REW
on
12.5
kHz
tie
Fig
5
Fig
6
eT}
ero
A.
CHANNEL
©
1
2
3
4
5
6
bs
J
*
UL
CHANNEL
©
1
2
STOP
L
sTop
Returns
qsthe
start
position
“a
R-ch
high-frequency
equalization
“<
L-ch
high-frequency
equalization.
level
detecting
point
level
detecting
point
REWIND
REWIND
REWIND
Fig.
4
No.
4198
Removal
of
the
Main
Parts
/b-@
Main
amp.
P.W.B.
assy
Mechanical
ass’y
Bracket
Fig.
7
No.
4198
|
DD-9A/B/C/E/J/U
Observe
care
in
handling
the
parts
since
the
parts
are
small
in
size
and
the
distance
between
them
are
short
due
to
a
deck
design
aimed
mainly
at
compactness
and
high
perfor-
mance.
(Remove
in
the
order
of
steps
1,
2,
3,
.....
)
Enclosure
assembly
parts
1.
Cassette
door
To
open
the
cassette
door,
push
on
the
eject
button.
Slide
off
the
cassette
door
upwards.
2.
Top
cover
Remove
5
screws
(a)
fastening
the
top
cover
(left
and
right
.....
2
screws
on
each
and
a
screw
on
rear
center).
3.
Bottom
cover
(1)
Remove
3
screws
(2)
(SDSP3008R)
and
a
washer
(3)
(WNS4000S).
—
These
screws
are
fastened
with
the
front
plate
ass’y.
(2)
Remove
5
screws
fastening
the
bottom
cover.
4.
Front
plate
assembly
Remove
5
screws
(5)
fastening
the
front
plate
upwards.
—
Enclosed
2
screws
for
mechanical
assembly.
Electrical
parts
When
removing
the
wires
from
wire
clamp
(QHX2075-001),
cut
off
its
clamp.
(This
clamp
cannot
be
used
again,
then
apply
a
new
clamp.)
1.
Remove
2
screws(6)
fastening
the
computer
P.W.
board.
Open
its
P.W.
board
from
left
side.
2.
Main
amp
P.W.B.
ass’y
(1)
Remove
4
screws
fastening
the
main
amp
P.W.
board
on
the
bottom
side.
(2)
Remove
3
screws
(8)
fastening
the
switches
on
the
front
side.
(3)
Remove
a
screw(9)
fastening
the
bracket
of
the
com-
puter
P.W.
board
on
the
right
side.
(4)
Pull
off
its
P.W.
board
to
rear
low
side.
3.
Level
indicator
P.W.B.
ass’y
(1)
Remove
2
screws
(10)
fastening
its
P.W.
board.
(2)
Remove
a
screw
(16)
fastening
the
bracket.
4.
Counter
P.W.B.
ass’y
Remove
a
screw
side.
fastening
its
P.W.
board
on
the
rigjt
5.
Power
supply
P.W.B.
ass’y
Remove
4
screws
©)
and
lugs
(3)
fastening
the
power
supply
P.W.B.
6.
Electronic
volume
VR
(1)
Remove
the
front
plate
assembly.
(2)
Remove
the
level
indicator
P.W.
board
ass‘y.
(3)
Remove
the
rope.
(4)
Remove
the
pulley.
(5)
Remove
the
computer
P.W.
board
ass’y.
(6)
Unsolder
3
wires
of
V.R.
board.
(7)
Remove
a
nut
and
a
washer
of
shaft.
(8)
Unsolder
the
V.R.
terminals.
7.
Switches
(Reset,
Memory,
etc.)
(1)
Remove
the
front
plate
assembly.
(2)
Remove
each
knob.
(3)
Remove
the
counter
belt.
(4)
Remove
a
screw
fastening
the
bracket
of
the
pulley.
(5)
Remove
2
screws
fastening
the
counter
P.W.
board.
(6)
Remove
5
screws
fastening
the
switches.
(7)
Pull
off
the
switch
P.W.B.
ass‘y
to
rear
side.
g
Volume
_-6GN,
motor
Front
bracket
?
~
A)
(left)
:
P
s
s
Pulley
aS}
Pulley
&
©
Washer
-
6
Nut
Rope
Counter
“le
display
knob
Fig.
8
Mechanical
assembly
(When
removing
the
front
plate
ass’y,
remove
2
screws
fastening
the
mechanical
assembly
upwards.)
1.
Remove
4
screws
(12)
(left
and
right
.....
2
screws
on
each)
fastening
the
mecha.
assembly
to
the
chassis.
2.
Remove
2
screws
43)
fastening
the
gear-oiled
damper
to
the
chassis,
3.
Remove
a
screw
fastening
the
arm
of
the
gear-oiled
damper.
(When
removing
the
cassette
holder,
to
remove
the
left
bracket,
remove
2
screws
fastening
its
bracket.)
4.
Remove
6
connectors
on
the
mecha.
control
P.W.
board.
5.
Open
the
vinyl
wire
clamp
for
head
wires
on
the
chassis
(bottom
side).
6.
Remove
the
counter
belt.
Mechanical
parts
Mechanical
parts
are
the
same
as
removal
of
model
DD-7.
Please
refer
to
the
service
manual
of
DD-7A/8/C/E/J/U
(No.
4195,
page
10).
Main
Adjustments
DD-9A/B/C/E/S/U
[I]
Equipment
and
measuring
instruments
used
for
adjustment
1.
Electrical
adjustment
1)
Electronic
voltmeter
2)
Audio
frequency
oscillator
(range:
50—20
kHz
and
output
0dB
with
impedance
600
(2)
3)
Attenuator
4)
Standard
tapes
for
REC/PB
Maxell
UD
—
SF
tape
..........
TDK
SA
—
SAtape...........
}
or
equivalent
JVC
ME
—
Metal
tape.....-.-.-.-.
5)
Reference
tapes
for
playback
(JVC
Test
Tape)
VTT-658
(for
head
azimuth
adj.)
VTT-656A-S
(for
motor
speed,
wow
flutter
adj.)
VTT-664
(for
Reference
Level
1
kHz)
VTT-675N
(for
playback
frequency
response)
6)
Resistor
600
{2
(for
attenuator
matching)
2.
Mechanical
adjustment
1)
Torque
testing
cassette
gauge
2)
Blank
tape
(C-120)
for
tape
running
checker.
[01]
Mechanical
adjustment
Electronic
Voltmeter.
Go
Z.
Audio
Freq.
Osc.
@e@e
weias
Scooo
DD-9
Fig.
9
(Adjust
the
mechanism
or
confirm
that
it
is
in
normal
operating
condition
prior
to
the
adjustment
of
the
electrical
circuit.)
Head
adjustment
Back-tension
pad
Spring
position
1.
After
installing
the
specified
parts
in
the
appropriate
positions:
A.
Snug
screw
(1)gently,
then
back
off
about
two
turns.
This
makes
the
heads
nearly
horizontal.
B.
Snug
screw
(2)
gently,
then
back
off
about
one
turn.
This
will
roughly
position
the
tape
in
the
center
of
the
tape
path.
For
tightening
screw
2),
use
a
home
make
screwdriver,
filed
down
to
the
specifications
shown
below.
The
same
screwdriver
can
be
used
to
tighten
screw
Q)
Pad
(attached
to
the
cassette)
Combination
head
Tape
Capstan
Pinch
roller
Screwdriver
1~2
mm
oe
ie
2—2,5
mm
Fig.
10
2.
Make
sure
that
the
moving
part
of
the
erase
head
assembly
moves
smoothly
around
the
pivot
of
screw
and
also
confirm
that
there
is
enough
clearance
(A)
in
the
play
mode.
3.
Next,
make
an
operational
adjustment.
Load
a
C-120
cassette
and
adjust
the
height
of
the
erase
head
by
turn-
ing
screw
Q).
Watching
that
the
tape
does
not
curl
at
the
guides
of
both
the
combination
and
erase
heads
is
indi-
cation
of
proper
adjustment.
Tape
Tape Tape
guide guide
guide
E=
Ee
E
———
Correct
Incorrect
Fig.
11
No.
4198
DD-9A/B/C/E/J/U
|
NOTES:
*
After
adjustment,
confirm
by
ear
that
recorded
4.
Adjusting
record/playback
head
azimuth
sounds
on
the
metal
tape
are
completely
erased.
Adjust
the
head
angle
with
the
screw(1)
until
the
reading
*
After
replacement
of
the
erase
or
record/play-
of
the
electronic
voltmeter
becomes
maximum
for
both
back
head,
slacken
the
associated
wire,
clamp
channels.
the
new
head,
then
confirm
that
this
new
head
performs
normal
operation.
Adjusting|
Standard
point
value
Remarks
Adjustment
Employ
a
torque
testing
cassette
tape
40—70
|
If
the
standard
torque
is
not
obtained,
for
the
checking.
replace
the
take-up
disc
assembly.
Checking
fast
Measure
the
torque
in
the
fast
forward
If
the
standard
torque
is
not
obtained,
forward
torque
mode
in
the
same
manner
as
in
the
clean
the
motor
pulley,
idler
disc
cir-
above.
cumference.
Checking
rewind
|
Measure
the
torque
in
the
rewind
mode
torque
in
the
same
manner
as
in
the
above.
Checking
wow
Connect
a
wow
and
flutter
meter
to
and
flutter
LINE
OUT
terminals.
Play
back
the
VTT-656A-S
test
tape.
Check
to
see
if
the
reading
of
the
meter
is
within
0.019%
(WRMS).
This
semi-fixed
resistor
is
no
adjustment.
Damping
gear
oil
Oil
employed
—
Torque
grease
specified
by
JVC
(KANTO
KASEI
GP-608V)
Applying
method
—
Apply
in
both
concaved
sections
as
shown
in
the
figure
13.
Apply
oil
here.
é
No.
4198
=10=
DD-9A/B/C/E/J/U
[MI]
Electrical
circuit
adjustment
location
=
Main
Amp.
P.W.
Board
(Parts
Ass’y
side
view)
=
a
ee
e
Ecnaeee
vRpoe
vR201
(
|
aR
H
\
U
VRBO!
R
|
PY
en
i
XY
I-—
Encoder
(Recording)
R
i
calibration
Dolby
C
adj.
Decoder
(Piayback)
;
calibration
Dolby
C
+
-
Playback
level
adj.
:
adj.
i
(Turning
inthe
direction
1
|
of
the
arrow
increases
L
\
i
the
playback
levels.)
|
L
1
TPIO2
|
|
TPIO4
(1
a
TEIO!
!
2
VRAO2
CG
|
A
VRAO!
C100
\}
7-PB
frequency
1
sf,
response.
'
R100
ai
(
1
\
|
TPIO3
RIO!
|
|
o
Computer
playback
gain
adj.
i
LR
Cl
~—Recording
level
adj.
'
{Turning
in
the
direction
of
the
arrow
Secon
sees
|
increases
the
recording
levels.)
|
nn
Bias
adj.
R
:
{Turning
in
the
direction
i
of
the
arrow
increases
!
|
ab
the
bias
current
value.)
\\
VR205}
LA
Front
vrios
|
—}}
L~
|VRIO8
|vRIO9
Z
a
fr
vRI
|
XL)
:
(Ft
Revel
ad).
i
KERR
a
|
|
\VR208
yasas
VR207
4
PT).
ae
eile
ial
a
ce
|
opi
ee
pees
ones
a2:
Soha
tn
Fig.
14
=
Computer
P.W.
Board
(Parts
Ass’y
side
view)
58
a
21m
CUT
R
c-
A/D
test
point
7
m
For
reference
sign!
output
¥RGOS
mout-L
level
adjustment
7
__
(Turning
in
the
direction
of
ALD
output
adjustment
the
arrow
increases
the
out-
(Turning
in
the
direction
put
levels.)
TEST
H
of
the
arrow
increases
bs
the
output
levels.)
p—-—IKHZ
&
2
125
1603
-
KHZ
fea
Clock
OSC
adjustment
—one—f
Clock
osc
400 kHz
y
Computer
IC
test
point
3
———4KHZ
®
se
Oo
@
Monitor
H
pa
“
XGO4
Front
@
Monitor
L
ef
Q@
VRGO4
f
Oo
7
__
Bias
voltage
adjustment
XN
(Turning
in
the
direction
of
\
the
arrow
increases
the
refer-—
ence
voltage
at
Metal
tape.)
Fig.
15
No.
4198
—-11—
DD-9A/B/C/E/J/U
=
FL
P.W.
Board
(Parts
Ass‘y
side
view)
Va
Front
For
FLO
cB
level
adjustment
(Turning
in
the
direction
of
the
arrow
increases
the
levels.)
VR701
U
VR501
U
VR601
L
R
Lo
Fig.
16
{1V]
Electrical
circuit
adjustment
procedure
The
DD-9
employs
a
combination
record/playback
head,
thus
permitting
monitoring
the
sound
being
recorded.
For
adjustment,
playback
of
the
recorded
sounds
is
there-
fore
possible
simply
by
switching
the
MONITOR
switch
from
SOURCE
to
TAPE.
(It
is
unnecessary
to
rewind
the
tape.)
In
the
steps
marked
by
an
asterisk
(*),
adjustment
should
be
performed,
however,
only
checking
is
sufficient
with
steps
other
than
those.
:
Adjusting
|
Standard
Decoder
(playback)
2,533
Bes
PB
level
adj.
1.
Off
the
Dolby
NR
switch.
2.
Apply
a
400
Hz
signal
to
PB
head
termi-
For
FL
—20
dB
level
adjustment
(Turning
in
the
direction
of
the
arrow
increases
the
levels.)
Adjustment
should
be
performed
in
the
order
of
steps,
1,
Perform
this
adjustment
with
the
Dolby
C
NR
—2.5
dBs
switch
set
to
OFF
and
output
level
control
set
to
maximum.
calibration
nal
(PB
level
adj.
VR
set
to
some
position).
|
VRAO1
—2.5
dBs
Dolby
C
Adjust
input
signal
so
that
TP101
output
BO1
adj.
level
becomes
—2.5
dBs.
3.
Adjust
VRAO1
and
BO1
so
that
TP102
output
level
becomes
—2.5
dBs.
PB
Kead
EQ
amp
Dolby
C
circuit
ICAOI
1cBor
PB
levet
adj
Oo
fey
TPIOI
TPIO2
400H27(Y,
VRAQ
2*
|
Adjusting
1.
Play
back
the
VTT-664
Reference
tape
|
VR101,
—4
dBs
This
adjustment
becomes
neces-
playback
(1
kHz)
with
the
tape
select
switch
set
to
201
(0.5
V)
sary
when
a
change
in
playback
level
the
SF/NORM
position.
level
results
(for
example,
due
to
2.
Adjust
VR101
and
VR201
until
the
LINE
head
replacement).
OUT
becomes
—4
dBs.
beat
3*
|
Playback
frequency
pened
response
No.
4198
aH
bom
YH
©
=
connection
When
soldering
of
pattern
slit
(R100,
C100)
open
as
1
>
2
>
3
steps,
gain
of
10
kHz
fre-
quency
response
increases
0.5
dBs
with
one
step.
ee
ee
Step
DD-9A/B/C/E/J/U
Item
Adjustment
Adjusting
|
Standard
point
value
Remarks
4*
FL
(Fluores-
cence
Level)
indicator
sensitivity
Nom
.
Set
the
METER
switch
to
VU.
.
Set the
MONITOR
switch
to
SOURCE,
then
apply
a
1kHz
signal
of
around
—20
dB
to
the
R-ch
and
L-ch
of
the
LINE
IN
terminals.
.
Adjust
the
INPUT
LEVEL
control
so
that
the
output
level
at
the
LINE
OUT
termi-
nals
is
—4
dB.
.
Adjust
VR701
(“0”
dB
level
adjustment)
so
that
“0”
dB
lights
at
both
R
and
L.
At
this
time,
‘’0’’
dB
must
go
out
at
both
R
and
L
with
the
input
ATT
(attenuation)
level
lowered
by
0.5
dB.
.
Lower
the
input
ATT
level
by
20
dB.
.
Adjust
VR501
(L-ch)
and
VR6O1
(R-ch)
so
that
““—20”
dB
lights
at
both
R
and
L.
At
this
time,
“—20’
dB
must
go
out
at
both
R
and
L
with
the
input
ATT
level
lowered
by
1
dB.
.
Repeat
steps
4.—
6.
VR701,
VR501,
VR601
0VU
—20
VU
Due
to
parts
replacement.
Encoder
(recording)
calibration
Dolby
C
adj.
=
.
Off
the
Dolby
C
NR
switch.
.
Apply
a
400
Hz
signal
to
LINE
IN.
(Bal-
ance
VR
set
to
center,
and
input
level
con-
trol
set
to
some
position.)
.
Adjust
input
signal
so
that
TP103
output
level
becomes
—2.5
dBs.
.
Adjust
VRAQ2
and
BO2
so
that
TP104
output
level
becomes
—2.5
dBs.
VRAO2
B02
LINE
IN
—2.5dBs
Dolby
C
circu
o
Balance
VR
<I
Input
TPIO3
level
control
VRAC2
1C
AO4
TPIO4
This
checking
should
be
per-
formed
for
normal,
chrome
and
metal
tapes
and
for
both
right
and
left
channels.
1.
Bias
current
adjustment
for
a
cassette
deck
should
generally
be
performed
referring
to
the
record/playback
frequency
response
of
a
cassette
deck
depends
more
greatly
upon
the
bias
current
than
does
that
of
an
open
reel
deck.
The
current
measuring
method
de-
scribed
below
in
an
alternative
2.
If
the
bias
current
is
not
pro-
perly
adjusted,
the
record
and
playback
characteristics
be-
come
as
shown
left.
LINE
IN
.
Balance
VR
set
to
center,
and
input
level
|
VR1
—4
dBs
level
L-ch
control
set
to
max.
and
R-ch
2.
Adjust
input
signal
so
that
output
level
of
deflection
L-ch
monitor
becomes
—4
dBs,
and
then
adj.
adjust
VR1
so
that
output
level
of
R-ch
monitor
becomes
—4
dBs.
Checking
Record
1
kHz,
50
Hz
and
12.5
kHz
signals
at
|
For
SF/
Reference
record/
an
input
level
of
O
VU
to
—20
dB.
NORM
}
frequency;
playback
Play
back
the
tape.
tape;
1
kHz
frequency
|
Check
to
see
that
the
50
Hz
and
12.5
kHz
VR107,
response
signal
output
deviations
fail
within
the
stan-
207
0+
3dB
dard
range,
using
the
1
kHz
signal
output
as
For
SA/
gt
Ue
y
CrO2
0+3dB
a
reference.
tape;
at
i
VR108,
|
12.5
kHz
ee
a
208
a
For
Metal
aS
tape;
8
j
VR109,
5
a
oe
level
209
ra
Decrease
in
high
frequencies
one.
o
(with
a
larger
bias
current)
50
Hz
1
kHz
12.5
Kz
Freauency
(Haz)
Adjusting
1.
Apply
a
1
kHz,
approx.
—10
dB
signal
to
|
VR105,
OVU
recording
the
LINE
IN
terminals.
Adjust
the
record-
205
level
ing
level
controls
until
the
signal
is
avail-
able
at
—4
dBs
at
the
LINE
OUT
termi-
nals.
.
After
checking
to
see
if
the
FL
indicator
becomes
0,
record
the
signal
applied
to
both
left
and
right
channels
using
normal
tape.
.
Play
back
the
recording
part.
Perform
the
recording
signal
adjustment
with
VR105
and
VR205
so
that
the
FL
indicator
be-
comes
0.
The
level
difference
between
left
and
right
channels
for
SF/NORM
tape,
chrome
tape
and
metal
tape
should
be
less
than
1
dB
(1
VU).
Perform
the
adjustment
using
a
normal
tape,
level
difference
be-
tween
recording
and
playback
;
for
SA/CrO2
and
metal
tapes,
should
be
less
than
1.5
dB,
and
that
between
left
and
right
chan-
nels
should
also
be
less
than
1dB.
=4Z
=
No.
4198
DD-9A/B/C/E/J/U
|
Item
7
Checking
4:
record/play-
back
signal
distortion
2.
FL
indicator
becomes
0.
Checking
1.
signal
to
noise
ratio
inrecord/
}2.
ing/playback
Record
a
1
kHz,
0
VU
signal.
Play
back
the
recorded
part.
Measure
the
0
VU
recording
output
and
the
non-signal
recording
output
for
com-
Parison
using
an
electronic
voltmeter.
Check
to
see
if
the
value
conforms
to
the
standard
value.
Adjustment
Adjusting
re
Remarks
point
value
Record
a1kHz,
—4dBs
signal
to
LINE
IN
SF/NORM
tape;
|
Be
sure
to
perform
this
ad-
terminals
and
perform
recording
with
the
Less
than
2.5%
|
justment
following
—
bias
SA/CrO2
tape;
|
current
and
recording
level
Play
back
the
recorded
part.
Check
the
Less
than
3%
adjustments.
output
with
a
distortion
meter
to
see
if
Metal
tape;
the
value
conforms
to
the
standard
value.
Less
than
2%
sj
S/F
NORM,
Apply
an
output
(—72
dBs)
Stop
the
input
by
disconnecting
from
the
SA/CrO2
and
to
the
MIC
terminals
with
terminal
to
perform
non-signal
recording.
Metal
tapes;
the
recording
level
More
than
trols
set
to
maximum
so
42
dB
that
the
FL
indicator
be-
con-
comes
0.
11.
|
Checking
1
erasing
coefficient
2
3
4
|
.
Perform
.
Apply
a
1kHz
signal
to
the
LINE
IN
terminals.
Adjust
the
recording
level
con-
trols
until
the
FL
indicator
becomes
0.
recording
with
the
signal
en-
hanced
by
20
cB.
.
Erase
a
part
of
the
recording.
.
Measure
the
output
difference
between
the
erased
part
and
non-erased
part
to
compare
with
an
electronic
voltmeter.
65
dB
More
than]
For
the
measuring,
connect
a
band
pass
filter
between
the
deck
and
the
electronic
voltmeter.
Input
(1kHz
OVU
+
20dB)
Tape
deck
(recording,
erasing)
Band
pass
filter
am)
Electronic
voltmeter
(1
kHz)
[V]
Adjustment
by
computer
checker
Use
the
checker
for
DD-9
(specified
by
JVC).
=
Adjustment
conditions
(connection
of
checker,
its
switch
positions,
etc.)
Alligator
clip
connecting
TEST
SW
TEST
PRO!
TEST
PRO|
The
places
with-
Checking
point
Post
pin
point
(com-
SW
2
SW
1
out
(__)
are
re-
(computer
board)
puter
board)
lated
to
the
com-
puter
board
1
Computer
clock
TG03
ey
point
(ICGO2,
2.4)
SOU
PURSE
Die
54
OFF
OFF OFF
OFF
(Checker)
set
check
Computer
oscil-
3
|
lation
adjust-
54
ON
ON
OFF
OFF
55
2,
6
I
ment
ai
4
|
A/D
adjustment
54
ON
ON
ON
ON
A/D
test
point
2,
6
——_—_—_}_
———
Sensitivity
and
|
medium-fre-
5
Seer
eaualr
54
ON
ON ON
ON
111,
211
57,46
Zation
level
switching
|
operation
Bias
adjustment
OFF
ON
OFF
ON
“Tired
nee
2,6
terminal)
——
+
———
Hiab
Wrequency
Remove
bias
cut
equalization
54
ON
ON
ON
OFF
(Record
head
hee
level
switching
terminal)
Operation
L
2,
6
Co
mputer
play-
When
emitting
sound
8
|
back
gain
53
ON/OFF
ON
OFF
OFF
55
from
LINE
OUT,
re-
adjustment
move
pin
9.
When
adjusting,
con-
nect
pin
9.
2,
6
No.
4198
4
=
Adjustment
procedures
(1)
Computer
clock
adjustment
Connect
a
counter
to
ICGO2
P1
(TP
CLOCK),
then
turn
the
core
of
TGQ3
so
that
the
oscillation
frequen-
cy
becomes
400
kHz.
(In
this
case,
connect
a
1
MQ
resistor
in
series
with
the
counter
input.)
(2)
Computer
preset
check
At
each
tape
position,
confirm
that
each
bit
is
equal
to
the
pertinent
value
in
the
table
below.
Medium-
High-frequency
Bias
|Sensitivity|
frequency
|
equalization
at
equalization
L/R
Normal]
14
7
3
4
FeCr
14
8
3
5
Metal
9 8
4
11
CrO2
14
7
3
5
|
Notes:
@
Concerning
the
FeCr
position,
set
the
TAPE
SELECT
switch
to
CrO2
with
Normal
or
FeCr
tape.
®
Concerning
the
CrO2
position,
set
the
TAPE
SELECT
switch
to
CrO2
with
CrO2
tape.
(3)
Computer
oscillation
adjustment
When
pressing
the
START
switch
with
the
set
(DD-9)
in
the
STOP
mode,
the
oscillation
switching
program
starts.
The
START
switch
not
pressing,
signals
are
repeatedly
emitted
in
the
order
of
1kHz
—
4kHz
—
8kHz
—
12.5
kHz
—
1
kHz
at
intervals
of
about
1.5
sec.
Connect
an
electronic
voltmeter
to
tab
55
(A/D
IN)
on
thecomputer
board,
adjust
the
oscillation
level
for
each
frequency
by
the
pertinent
half-fixed
resistor.
Frequency
|
Half-fixed
resistor
|
Adjustment
value
1.0kHz
VRGO4
—27
dB
4.0
kHz
VRGO3
—28
dB
8.3
kHz
VRGO2
—27
dB
12.5kHz
VRGO1
—25
dB
Note:When
pressing
the
START
switch
in
arbitrary
output
mode,
it is
possible
to
keep
this
output
mode.
(4)
A/D
adjustment
With
the
START
switch
pressed
and
the
set
in
the
STOP
mode,
confirm
that
the
A/D
counter
operates.
Next,
connect
an
oscilloscope
(DC
couple)
to
the
A/D
test
point,
then
confirm
that
the
waveform
shownat
right
appears.
Adjust
VRGO5
so
that
the
indication
of
the
A/D
counter
is
64.
When
releasing
the
START
switch,
the
sensitivity
switching
operation
is
performed.
DD-9A/B/C/E/J/U
2.2V
Ov
About
24
msec
About
40
msec
Fig.
17
(5)
Sensitivity
and
medium-frequency
equalization
level
switching
operation
When
releasing
the
START
switch
after
A/D
adjust-
ment,
confirm
that
the
bit
for
SENS,
switches.
Next,
confirm
that
the
bit
for
M.
EQ
switches,
remove
post
pin
and
connect
an
electronic
voltmeter
to
tabs
and
.
Then,
confirm
that
the
output
changes
step
by
step.
SENS
M.
EQ
1
kHz
4
kHz
(5
O00
7
1B
Oe
Fig.
18
(6
Bias
adjustment
Press
the
START
switch
with
the
set
in
the
STOP
mode,
then
confirm
that
the
bit
for
BIAS
switches
from
15
through
0.
Next,
put
the
set
into
the
REC
PAUSE
mode,
then
confirm
that
the
record
head
current
changes
step
by
step.
Fig.
19
Note:
Set
the
bias
for
metal
tapes
(adjust
VRGO6)
and
adjust
the
oscillation
frequency.
@
Adjust
VRGO6
so
that
emitter
voltage
of
XG04
becomes
10.6
V.
@
Adjust
TGO1
so
that
bias
frequency
becomes
95
kHz.
@
Adjust
TGO2
so
that
bias
tuning
becomes
peak
point.
No.
4198
DD-9A/B/C/E/J/U
(7)
High-frequency
equalization
level
switching
operation
With
the
set
in
the
STOP
mode,
remove
bias
cut
pin
(8)
on
the
computer
board.
Press
the
START
switch,
then
confirm
that
the
bit
for
H.
EQ.
switches.
Next,
with
the
set
in
the
REC
PAUSE
mode,
confirm
that
the
head
current
changes
step
by
step.
[12.5
KHz
Preset
-O----5-)-+10----6O----5-
Fig.
20
(8)
Computer
playback
gain
adjustment
(9
Using
a
1
kHz
reference
playback
tape
with
the
set
in
the
STOP
mode,
push
up
the
AR
switch
and
press
the
START
switch.
Then,
release
the
AR
switch
after
confirming
that
the
set
has
begun
the
test
program.
Next,
remove
post
pin
on
the
computer
board.
After
confirming
that
the
output
level
at
LINE
OUT
is
—4
dB,
connect
post
pin
Q)
as
before,
connect
an
electronic
voltmeter
to
tab
[55]
on
the
computer
board,
then
adjust
VRAO3
and
VRBO3
on
the
main
amplifier
board
so
that
the
output
level
is
—10.5
dB.
The
output
at
R
channel
goes
OFF,
when
the
MONI-
TOR
switch
is
ON
and
the
output
at
L
channel
is
OFF,
Record/playback
check
in
computer
switching
oper-
ation
Remove
post
pin
(9)
on
the
computer
board,
apply
a
singal
of
—20
dB
to
LINE
IN
and
select
a
suitable
test
program.
Next,
press
the
START
switch
after
stopping
the
input
at
each
operation,
then
change
the
REC
mode
to
the
PLAY
mode.
Enter
a
frequency
corresponding
to
each
test
pro-
gram,
then
check
the
output.
(Set
the
Dolby
C
NR
switches
to
OFF
and
use
the
normal
UD
tape.)
@
Explanation
of
diagrams
Fig.
21:
BIAS:
8.3
kHz,
—20
dB
Fig.
22:
SENS
(sensitivity):
1.0
kHz,
-20
dB
Fig.
23:
M.
EQ.
(medium-frequency
equalization
level):
4.0
kHz,
—20
dB
Fig.
24:
H.
EQ.
(high-frequency
equalization
level):
12.5
kHz,
—20
dB
No.
4198
1G
=
=25
BIAS
8
3KHZ
Ret
-204B
Gao
UD
ae
oBeg
30
|
/
Sy
|
|
iS
14 13
12
No
1
9
8@
F
6
5
4
3
2
Co)
Fig.
21
SENS
IKHZ
Ref
-20dB
ud
-20
ir
el
-25
aa
re
ai
a
al
-30
14
13
1
WM
10
9
8
F
6 5
4
3 2
1
0
Fig.
22
MEQ
4KHZ
Ref
-2048
10
IKHZ
Ref
-20
4B
UD
5
f—
4KHZ
X¥
SENS
O
+47ds
oe
fetid
soaps
Rear
tee
i
207
--
On
WB
Bh
g
1
He
Fig.
23
°
HEO
12.
5KHZ
Ref
-20d8
ae
5
oa
as]
-10
a
ee
-15
-
20
oO
1
2 3
4
5
6 7
8
8
10
1
2
13
4
15
Block
Diagram
(1)
=
Mecha.
control
circuit
ndi
r
Indicators
5V
REC
PAUSE
PLAY
REW
FF
Remote
control
socket
(¥)
(¥)
’)
Cassette
V
Operation
5
Control
IC
buttons
1C801
REW
OFF
PAUSE
M54866P
O
O
O
exams
Gees
Play
solenoid
board
a
(ee
|
river
RECO
X804
2SD571
X805,806
2SC945L
X807
2SB605
O
REC
MUTE
Brake
solenoid
X809
2SC945L
Play
solenoid
cS
0
DD-9A/B/C/E/J/U
driver
Brake
solenoid
X801,802 |
eae
2SC945L
Q
Reel
motor
drive
circuit]
X803
2SD571
50/60
Hz
X8!13,814
selector
2SD571
Power
supply
ie
i
‘
X812,815,816
for
Reel
motor
PLAYS)
XKOI,KO2
o
1
Rec.
proof
817,818
circult
PAUSE
2SC945L
as
secede
Counter
IC
Counter
FL
5
3-8
_
_
Cassette
(M)
6
Q 9
1
switch
Pp
|
ls
_|
ower
supply
Reel
motor
1
\
for
Motor
2,
Les
Capstan
motor
a
ie
M8523H
el
ae
To
Stop
circuit
6
er
KII
Mee
eew
Stop
circuit
a
si
STOP/PLAY
PAUSE
DELAY
control
(BES)
Memory
stop
ASeS
BES
68]
xGi7
ne
STOP
vaGd
2SC945L 25C945L
Memory
stop
/\
(QA,PA)
XKOG
muting
2SC945L
pso2
(QA,PA)]|
US1035
2SC945L
XKO5
|
(PA,KA)
2SD636
M
-
Auto
stop
One
shot
Micro-computer
R
Ss
agne
Hall
IC
circuit
multi
circuit
Micro-computer
IC
output
selector
Ol
detector
Signal
wave
>
control
XKO3
25A733A(P,K)
Fig.
25
Sy
7—
No.
4198
DD-9A/B/C/E/J/U
Block
Diagram
(2)
=
Record,
playback
and
computer
circuit
=
FL
meter
circuit
PBgain
adjustment
Pre-amplifier
P.B.EQ.
selector
Dolby
C
Circuit(PB)
X101
~
X105
IC
AO1,
A02
®
layback
~x
OP
y
hae
ae
x
XAQ1~
XA05
vibe
©)
Headphone
amplifier
VR102,
202
VR101
VR103
PBfrequency
4
IC
COl
IC
01
Headpone
jack
adjustment
?
a
XAI3
|
Dolby
B/C,
OFF
—20dB
adjustment
1€103
Select
Micro-computer
InputVR
XC
O1~
XC
03
Rk:
circuit
VR701
LINE
IN
Meter
OdB
control
Input
selector
ae
Left/Right
Micro-computer
J
Microphone
amplifier
'
PB/REC
converte!
ICGIO__
circuit
i
VRAQ3
selector
|
control
Microphone
X107~
X109
P
ICAO3,
AOs
12%
IC51
selector
=
eS
XAD6~XAI2_
Te
Ra.
ate
orl!
Icoi4
<b
Gis
arts
Micro=
Ql,
”
REC/BES
Rch
ircui
oN,
1@,
|
Peak-hold
typel
@F-7O
circuit
Balance
VR
Input
VR
Dolby
C
Circuit
(REC
eS
an
=
Hed
selector
oa
Test
signal
:
MONH
Recording
melas
TAR
2s
iLIest
sign’
ee
lcclor
O@IC52_VRI05,205
X113
IcGoB._ICE2
amp.
ICGO1
filter
ICGO1
C
CrO2
EQ
Sensitivity
Middle-
Middle—
(2
MD
aa
3)
x
select
o—
selector
Eeaency
frequencyt—o
~~
Recording
ICGI5S
BLe
@
circuit
ec
ICEO1
sub-am
selector
IC102
A
head
Recording
Emitter
LHEL
incuit
of
6
0
eve
j
]
el
t
OSC
circui
:
al
.
OSC
adjustment
follower
aad
ahg
Middle
Counter
er
ror
le
Cue
8,3
KHz
)
filter
frequency
High-f
Micro-
ICG13
igh-freqency
:
ating
Mas
compute
uit
a
Micro
ficeogroa|
rade
ae
ae
os
ircul
,
if
FC2H
|
control
x11
Circuit
FC2H
computerf—*Micro.
Metal
&
FeCr
computer
:
head
|
ei
Micro-
FCIH
EKEE
FCIH
Reset
pone
4
signals
MER
circust
computer
XG03.16
XG0405
VR
107,109
;
a
:
Muting
circuit
VR
207,
209
Micro-computer
ilter
Micro-computer
LH8H-IH
:
Circuit circuit
Mecha.
con.
REC
MUTE
ICGO4
SENS
Dolby
C
Block
Diagram
Tape
XG01,02
mode
control
control
asses
Deel
cent
ote
CEN,
EEE
Ce
ae
ot
Se
ahs
ds
BV8L~
BVIL
Micro-computer
circuit
Mecha.con.
output
select
|
ICGO5
|
()
I
|
!
To
Mecha.con.
@
:
REC/
REW
FCIH
OVER
SHOOT
|
rd
Micro-computer\
Lo
_
_
_
_
_
UIMITTER
|
fot
To
Mecha.
con.
G)
circuit
ce
STOP
|
—>
|
a
|
\
'@
Micro-computer
oF]
*
circuit
.
MAH
OVER
SHOOT
ee
ee
es
ee
eee
z
L__—
LIMITER
follower
To
Mecha.con.
REC/REW
t
=
a
TAPE
Lch
To
Mecha.con.
PLAY/
FF
Monitor
|
SKEWING
FILTER
SATURATION
NETWORK
OVER
SHOOT
LIMITTER
No.
4198
This manual suits for next models
5
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