JVC KD-A11 User manual

MODEL
KD-A11 A/B/C/E/J/U
STEREO CASSETTE DECK
No. 4192
June 1980

KD-A11A/B/C/E/J/U
Contents
Page
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Specifications
Type
Track system
Tape speed
Frequency response:
(O VU recording)
Metal tape
SA/Chrome tape
SF/Normal tape
(-20 VU recording)
Metal tape
SA/Chrome tape
SF/Normal tape
: Stereo cassette deck
: 4-track, 2-channel
: 1-7/8 inch/sec (4.8 cm/sec)
*1 ;40-11,000 Hz (+3 dB)
*2;40-8,000 Hz (+3dB)
*3 ;40—8,000Hz (+3 dB)
*1 ;30—16,000 Hz
40—15,000 Hz (+3 dB)
*2 ;30—16,000 Hz
40—15,000 Hz (+3 dB)
*3 ;30—15,000 Hz
40-—14,000 Hz (+3 dB)
Surpasses DIN 45 500
Note: *1... SCOTCH METAFINE or Equivalent
*2.... TDK SA or Equivalent
*3 ... MAXELL UD or Equivalent
S/N ratio
Wow and flutter
Crosstalk
Harmonic distortion
Bias
Erasure
Heads
No. 4192
: 60 dB (from peak level,
weighted, Metal tape)
The S/N is improved by 5 dB at
1 kHz and by 10 dB above 5 kHz
with DOLBY N.R. on
(DIN 45 500 weighted)
: 0.05% (WRMS),
0.15% (DIN 45 500)
: 65 dB (1 kHz)
: K3; 0.5%, THD; 1.0%
(metal tape, 1 kHz 0 VU)
: AC bias
: AC erasure
: 2 heads
METAPERM head for recording/
playback and 2-gap ferrite head
for. erasure
Motor :
Fast forward time :
Rewind time
Semiconductors
Input terminals
Mic jack x 2 :
Input jackx2 ;
Output terminals
Output jack x 2;
Phones jack x 1 ;
DIN socket
Power requirement :
Power consumption:
Dimensions
Weight
Electronic governed DC motor
95 sec. with C-60 cassette
95 sec. with C-60 cassette
3 1Cs, 21 transistors, 17 diodes 1 LED
Max. sensitivity; 0.2mV
(-72 dBs)
Matching impednace;
6002 — 10k2
Min. input level; 80mV
(-20 dBs)
Input impedance; 100kQ2
Output level; 300mV
Output impedance; 5kQ
Output level; 0.3mW (822)
Matching impedance;
BQ — 1kQ
Min. input level; 0.1mV/kQ
Input impedance; 10kQ
Output level; 380mV
Output impedance; 5kQ
AC
240V,
50Hz
(KD-A11A)
AC 240/220/120V, 50/60Hz
(KD-A11 B/C/E/J)
AC 240/220/120/100V,
50/60 Hz (KD-A11U)
10W
16-1/2" (420 mm)W
5-1/4" (134 mm)H
10-3/8"'(264mm)D
9.9 Ibs (4.5 kg)
Design and specifications are subject to change
without notice.
me ee

an,
KD-A11A/B/C/E/J/U
Features
@ Single lever 4-stage tape select switch makes the KD-A11 are assured through employment of IC-built circuitry.
compatible with all types of tape including the new (Dolby ”* is trademark of Dolby Laboratories Inc.)
metal Tape format. (else Reduction System manufactured under Rees)
® {C-built Dolby* Noise Reduction System from Dolby Laboratories Inc.
Dolby System greatly improves performance by cutting @ METAPERM head for recording/play back
out tape hiss, without changing the original music, thus 2 Gap ferrite head for erasure
making it every bit as good as professional standard type © Automatic input select
open reel tapes. High reliability and optimum quality
Controls and Connections
°0 @e8 ®@
tweninecy — FEC/PLAY we outipcay)
R L
@@O WU meters ® Cassette operation buttons.
@ Recording indicator (REC) @4 STOP/EJECT button
@ Cassette holder <<) REWIND button
@ Tape COUNTER/counter reset button oO Record button (REC)
@ POWER switch >» PLAY button
@ PHONES jack >> FF button
@ MIC jacks 1 PAUSE button
@ REC LEVEL controls @® Voltage select switch (KD-A11 B/C/E/J/U)
@ TAPE SELECT switch @® LINE IN (REC) terminals
@ Dolby noise reduction switch (DOLBY NR) @® DIN (REC/PLAY) socket
@® LINE OUT (PLAY) terminals
@ Power cord
SAR us No. 4192

~ KD-A11A/B/C/E/J/U
Main Parts Location
)@ @) 4)
No. 4192
Flywheel/capstan belt
Auto stop solenoid
Motor
Recording indicator P.W.B.
Meter cover
Remote bar
Power switch P.W.B.
Main Amp P.W.B.
Recording spring
Power Transformer
. Oiled-gear damper assembly
. Reed switch P.W.B.
OANOAIPWNH>
-_— — —
N=
(Mechanical parts)
1. Pinch roller arm assembly
2. Pinch roller spring
3. REC/PB Head
4. Erase Head
5. Pause switch
6. Flywheel
7. Motor switch
8. Take up reel disc ass’y
9. Supply reel disc assy
10. Recording safety lever
11. Take up idler assembly
12. Stop/eject bar assembly
13. Rewind bar assembly
14, Recording bar assembly
15. Play bar assembly
16. Fast forward bar assembly
17. Pause bar assembly
18. Motor
19. Flywheel/Motor bracket
oon

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
frequency 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 rollar and capstan
Do the same method 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.
1 KD-A11A/B/C/E/J/U
Demagnetizing
The heads are made from a material resistant to magneti-
zation, but after long use they become magnetized.
A magnet brought into their vicinity can magnretize 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 viny! 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 screw-
driver, for example) near the head as this will increase
noise.
Removal of the Main Parts
Observe care in handing 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 performance.
Screw (1)
Lever Knobs
Control Knobs
ENCLOSURE ASSEMBLY PARTS
Cassette lid ..........
1) To open the cassette lid, push on the eject lever.
Remove a screw (1) fastening the cassette lid. (its right
low side)
Be careful of holding a nut.
2) Pull off the cassette lid to upper side.
TOP Cover .......0-
Remove 6 screws (left and right ..... 3 screws (2) on each)
Control knobs (REC LEVEL) ..........
Pull off them to forward.
Lever knobs (TAPE SELECT, DOLBY NR) .........-
Pull off them to forward.
Bottom cover ..........
Remove 3 screws fastening the bottom cover. (center
screw is long size.)
Remove the bottom cover from 3 pawls of mold chassis.
= No, 4192

KD-A11A/B/C/E/J/U |
Front plate assembly ..........
Remove 5 screws (3 screws (3) on upper side and 2
screws (4) on bottom side.) fastening the front plate
assembly.
(Top View) (Bottom View)
Screws ® This screw is fastened
with same as earth wire.
Front panel assembly
1. Remove a screw(S) fastening the button escutcheon
ass’y (left side)
2. Open the cassette holder, and remove a screw fastening
the arm ass‘y for oiled-gear damper.
3. Remove 4 screws (6) fastening the front panel. (left and
right ..... 2 screws on each)
4. Remove a washer and a nut @) fastening the REC
LEVEL control VR shaft.
5. Remove a screw (8) fastening the lever switch on main
amp P.W. Board ass’y.
(Mechanical assembly is removed with the same as front
panel.)
Screws @)
Washer and nut Screw Screw ()
MECHANICAL ASSEMBLY
1. Remove the counter belt from counter. 2) Remove 4 screws (Q) fastening the front plate.
2. Remove 4 screws (Q) fastening the front panel. (When assembling the mechanical control plate, it need a
new parts = the mechanical control plate cannot use
If you remove the mechanical assembly with not removed
the front panel, do the following method.
1) Remove the mecha control plate.
again.)
Screws @)
Screws (9)
No.
4192
a

Aten,
ELECTRICAL PARTS (Main amp P.W. Board ass’y)
1) Remove a nut and a washer fastening the REC LEVEL
control VR shaft.
2) Remove a screw fastening the lever switch.
3) Remove 3 screws fastening the main amp P.W. Board.
Koa 1A/B/C/E/S/U
4) Remove 2 plastic rivets fastening the PIN jack assembly.
5) Remove the record spring.
6) Remove 4 pawls for holding the main amp P.W. Board.
Plastic
rivet
paw! =>
Recording
spring
(Top View)
@ Supply disc assembly
Stop cover
Take up disc assembly
Lock bush
Take up sping
Gear base
E Head REC/PB Head} Pinch roller
arm ass‘y
(Front View) Take up idler arm ass’y
: Ee
Screw .
=
MECHANICAL PARTS
1. REC/PB head ..........
Remove a screw (1)
Remove a screw (2) for adjustment.
2. Erase head ..........
Remove a ea
Remove a screw () for adjustment.
3. Pinch roller arm ass’y ..........
Remove an E-ring ® holding its assembly.
Pull it off from the shaft.
4. Supply reel disc ..........
Pull out the reel disc stopper © and pull out its
disc from shaft.
5. Take-up reel disc ..........
Pull out the ree! disc stopper @) and remove the
counter belt, pull out its disc from shaft.
Note: (1) Remove the reel disc stoppers with a piece of
sheet metal inserted between the reel disc and
the stopper. (When assembling the reel disk, the
stopper need a new parts. (the stopper can not
use again.)
(2) Be careful not to stain the counter belt.
No. 4192

KD-A11A/B/C/E/J/U
(8) Screws
Rubber stopper \
aT Set screw
dQ Screws
(Rear View)
9? 3 screw
es 3 cushions
1.0mm
+£0.2mm
Gear frame ass‘y aa
Brake drum
a Rack plate
~ E (4)
@— Of a
No. 4192
, o
D
assy
Flywheel assembly
1. Remove 3 screws (8) and a set screw (Q) fastening the
flywheel and motor bracket.
2. Remove a capstan belt.
3. Remove 3 screws fastening the capstan metal.
4. Remove the pressure lock bushing and the take up spring
on front side, and then remove the take up idler arm
assembly.
5. Remove the pressure position of stopper cover, and
move the gear base to supply disc direction, and then
remove the gear base tip from the groove of capstan
metal.
6. Pull off the flywheel assembly.
Note: When assembling the flywheel, fasten the screws
after assembled the chassis to the groove of capstan
metal.
Motor
1) Remove a screw fastening the rubber stopper.
2) Remove the capstan belt from the motor
pulley.
3) To remove the motor, turn it in counter-
clockwise direction and pull it out backward
(with 3 cushions and 3 screws for fastening
the motor).
Note: When replacing the motor, check the following
points.
(1) Is the motor placed in correct position?
(Don’t make the motor’s position deflective.)
(2) Does the capstan belt run in the center of the
motor pulley?
DOOR BRAKE AND ITS RELATED PARTS
1. Gear frame ass’y .......
2. Brake arm and tire
spring @.
3. Spur gear and brake drum
spring @).
4. Rack plate ....... Remove the screw and the collar @).
5. Brake lever ass’y ....... Remove the E-ring ©.
Remove a screw @.
wasters Remove the E-ring and torsion
Remove the E-ring, and
PB,

etn
Main Adjustments
[1]
1.
[11]
Equipment
and
measuring
instruments
used
for
adjustment.
Electrical adjustment
1) Electronic voltmeter
2) Audio frequency oscillator
(range; 50-20 kHz and output 0 dB with impedance
600 &2)
3) Attenuator
4) Standard tapes for REC/PB
SONY CS-30 — FeCr tape
BASF T308S — NORMAL tape
BASF C401R — CrO2 tape
SCOTCH METAFINE — METAL tape
5) Reference tapes for playback (JVC Test Tape)
VTT-658 (for head azimuth adj.)
VTT-656 (for motor speed, wow flutter adj.)
VTT-664 (for Reference level 1 kHz)
VTT-675N (for playback frequency response)
6) Resistors
100 22 (for measurement of the bias current)
600 {2 (for attenuator matching)
or equivalent
. Mechanical adjustment
1) Gauge for checking the head position.
2) Torque gauge
3) Blank tape (C-120) for tape running checker.
Adjustment and repair of the mechanism
Audio Freq. Osc.
La
KD-A11A/B/C/E/J/U
Electronic
Voltmeter _,
Attenuator
oe
S304 “13 6000
OUT/PUT
(Adjust
the
mechanism
or
confirm
that
it is
in
normal
Operating
condition
prior
to
the
adjustment
of
the
electrical
circuit.)
Adjusting record/
playback head
position
Adjusting erase
head height
. Connect an electronic voltmeter to
the LINE OUT terminals.
2. Play back the VTT-658 test tape.
3. Adjust the head angle with the
screw (@) until the reading of the
electronic voltmeter becomes max-
imum for both channels.
4. After adjusting, set the screw with
screw bond.
Tape-to-head contact adjustment
1. Turn the adjusting screw for
aligning the erase head until it stops.
Then, turn the screw in the re-
verse direction by 180° (a % revolu-
tion).
2. Employ a special cassette (C-120)
© from which parts to the casing,
where the erase head, record/play
back head and capstan engage, has
been cut away. Perform tape trans-
port with the cassette tape. Adjust
the screw until the tape runs in
the center of the egase head tape
guide.
3. Check it again with a BASF C401R-
CrOQ2 tape.
Checking method:
Record a 400 Hz or 1 kHz signal
with OVU+20dB. Erase the record-
ing. Check if the erasing is satisfac-
torily performed.
4. After adjustment, apply screw bond
on the adjusting screw to prevent
its loosening.
Proper
Tape guide
EF
Improper
ct
Screw
®
Maximum
|
1.
If
the
head
is
worn,
disconnected
or
exceedingly magnetized so as not to
provide the necessary characteris-
tics, replace it with a new one.
After replacement, the head posi-
tion adjustment as well as the play-
back level adjustment, the bias cur-
rent adjustment and the recording
level adjustment are all necessary.
2. If the output difference between
the left and right channels exceeds
3—4 dB, the head is defective.
Replace it with a new one.
Be sure to perform this adjustment
after replacing the erase head.

KD-A11A/B/C/E/J/U |
Adjusting | Standard
point value
Adjusting motor Connect a speed meter to the LINE Semi-fixed| 3000 Hz_ | If the speed meter functions as a wow
speed OUT terminals. Play back the VTT- resistor in and flutter meter, also, connect the
656 test tape Adjust the semi-fixed the motor deck to the INPUT terminals of the
resistor in the motor until the read- meter.
ing of the speed meter is 3000 Hz.
Checking
play-
Employ
a
torque
testing
cassette
tape
If
the
standard
torque
is
not
obtained,
back
torque
for
the
checking,
or
remove
the
cas-
replace
the
take-up
reel
disc
assembly.
sette
cover
and
use
a
torque
gauge.
Checking
fast
Measure
the
torque
in
the
fast
forward
More
than
|
If
the
standard
torque
is
not
obtained,
forward
torque
mode
in
the
same
manner
as
in
the
80
gr-cm
|
perform
the
following.
above.
1.
Clean
the
capstan
belt,
the
idler
cir-
cumference,
the
motor
pulley,
the
take-up
reel
disc
circumference,
the
flywheel
circumference,
etc.
.
Replace
the capstan
belt
or
idler
ass’y.
Checking
rewind
Measure
the
torque
in
the
rewind
More
than
|
If
the
standard
torque
is
not
obtained,
.
torque
mode
in
the same
manner
as in
the
80
gr-cm_ |
clean
the capstan
belt,
idler,
motor
above.
pulley,
flywheel
circumference,
supply
reel disc
circumference,
etc.
[111] Repair of wow flutter
If wow and flutter increase, check the following points. If tions.
there
is
defect
in
revolving
parts,
the
wow
and
flutter
gener-
Play
a
3000
Hz
test
tape,
and
defective
part
can
be
detected
ated will increase in proportion to the number of revolu- from the sound.
Replace flywheel.
Clean the capstan shaft in the flywheel.
Replace the capstan assembly.
Capstan shaft has excessive run-out.
Flywheel! turns heavily.
(shaft seisure, thrust play, etc.)
Pinch roller Rough rotation (Deformation scratches, | Replace pinch roller, or pinch roller spring.
or dust) Clean the pinch roller.
The angular position of the pinch roller | Adjust the pinch roller so that it is parallel with the capstan shaft.
is not correct.
The pinch roller pressure is not correct.
Belt Belt has undue run-out. Check the belt.
Belt is dirty or slippery. Replace the belt.
Back tension | Back tension is irregular, or back ten- Replace back compression spring (under supply disc).
sion is too strong.
Motor Motor shaft has undue run-out. Replace motor.
Motor pulley is oily and dustry. Clean motor pulley.
Capstan and
flywheel
No.
4192
—10—