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).