JVC KD-2A User manual

JVC
KD-2A/B/C/E/J/U
PORLABLE STEREO (GASo ETE, DECK
No. 4151
January 1977

No. 4151
KD-2A/B/C/E/J/U
Contents
Page
Specifications ©... 0... cee ee ee ee 2
Features: 6:6 scdiis a seis iatge tee se Sie elated ee hee ea 3
Controls and Connections ... 0... 002 eee eee eens 3
Main parts Location .. 2.0.2... 2000 e eee 4
Main Parts Removing
Enclosure
Assembly
.......--0202
ee
ee
eeee
5
Electrical
Parts...
0...
ce
ee
ee
ee
te
eee
6
Mechanical Parts .....---.00 0c ee eee eens 7
Main Adjustments
Electrical
Adjustment
.........00022
22
eee
8
Mechanical Adjustment ........-- 00 0e eee eee 12
Maintenance .......- 000 eee eee eee eee 14
Block
Diagram
2...
2.
ee
eee
ee
15
Specifications
Type Portable stereo cassette deck
Track system 4-track, 2-channel
Cassettes C-30, C-60, C-90
Tape speed 4.8cm/sec
Frequency response
Chrome *1 25~ 18,000Hz (Nominal)
30~16,000Hz (Typical)
Regular *2 25~17,000Hz (Nominal)
30~15,000Hz (Typical)
Supasses DIN 45500
*1 ~~ TP-18 or Equivalent
*2 OP-12 or Equivalent
57dB (from peak level, weighted)
The S/N is improved by 5dB at
1kHz and by 10dB above 5kHz
with ANRS on.
62dB with ANRS
(DIN 45500, weighted)
Effect of Super ANRS (Normal tape)
Improvement of
Signal-to-Noise ratio
Improvement of
frequency response
Signal-to-Noise ratio
the same as with ANRS
OVU recording; 6dB at 10kHz
+5VU recording; 12dB at 10kHz
Improvement of
distortion OVU recording; 3% or less at 10kHz
+5dB recording; 3% or less at 10kHz
0.09% (WRMS)
0.20% (DIN 45511)
Wow and flutter
Separation 35dB
Harmonic distortion 1.2% (Normal tape 1kHz, OVU)
Bias : AC bias (95kHz)
Erasure : AC erasure
Heads 2 heads
SA head for recording/playback
and ferrite head for erasure
Motor DC coreless motor
2 x 30 minutes with the
C-60 cassette
Less than 90 sec (with the C-60
cassette)
Recording time
Fast Forward time
Page
Circuit Board Parts
Main Amp Circuit Board Parts List ...........+- 16
REC Amp Circuit Board .. 0.0... 0.02.2 ee ee ees 20
ANRS Circuit Board ......-.---2- 200 eee eee 22
Mechanical Component (1) .. 2.2.0.0. 002s eens 25
Mechanical Component (2) .......-.000 eee eee 26
Mechanical Component List .............002055 27
Enclosure Ass’y and Electrical Parts
Except Circuit Board Parts (1).........2.2+05. 29
Except Circuit Board Parts (2).........-5-006- 30
Wii AG os eee eee ahh eee 8 ace lent BS ee aap se as Sys 32
Standard Schematic Diagram .......-. 2000s eee 33
Accessories 1... ce ee te ete tee ee 35
PACK iQ eso 'S aces sien esinte tig Roast da IOS Leta ea ee hae 36
Rewind time
Semiconductors
Input jacks
Output jacks
Recording connector
(REC/PB)
Power supply
Power consumption
Battery life
Dimensions
Weight
Less than 90 sec (with the C-60
cassette) per track
IC; 4, Transistor; 37,
Diodes; 25, SCR; 1
Mic jack; 2
Max. sensitivity; 0.2mV (-72dBs)
Matching impedance;
6002 (2002~2k2)
Input jack; 2
Max. sensitivity; 78mV (-20dBs)
Input impedance; 100kQ
Output jack; 2
Output level; 5|00mV (fixed)
Output impedance; 2.5k{2
Matching impendnce;
50k{2 or more
Headphone jack; 1
Output level; 0.75mW
Matching impedance; 82
Min. input level; 0.2mV/kQ
Input impedance; 2.2kQ
Output level; 5|00mV
Output impedance; 2.5k{2
Matching load impedance;
50kQ2 or more
DC 6V (“D” size CELL x 4)
External DC power; 6V
AC power;
120V, 60Hz for KD-2J/C
120/220/240V, 50Hz for
KD-2A/B/E
100V, 115V 230V
50/60Hz for KD-2U
5.5W (KD-2J/C) 6W (IKD-2A/B/E/U)
Approx. 6 hours of continuous
recording (on super type batteries)
10-7/8 (width) x 3-3/4 (height)
x 11-3/8 (depth) in.
8.8 Ibs. (including 4 batteries)
Design and specifications are subject to change without notice.

KD-2A/B/C/E/J/U
Features
Full auto stop.
Dual ball cassette holder
Automatic selector of stereo/mono for MIC record.
Built-in headphone volume.
Input select switch
* Compact and feather portable type.
* Power-saving design.
* Coreless motor.
* Built-in ANRS and Super ANRS.
* Sen-alloy head.
+ + + H
Controls and Connections
2 ®8888Oa0q8
1. Battery holder 18. Left auxiliary output jack [LINE OUT-L]
2. ACsocket 19. Right auxiliary output jack [LINE OUT-R]
3. DC Input jack (DC 6V) 20. Left auxiliary input jack [LINE IN-L]
4, Cassette cover 21. Right auxiliary input jack [LINE IN-R]
5. Bias switch [BIAS] 22. DIN socket [REC/PB]
6. Equalizer switch [EQ] 23. Input select switch [INPUT SELECT]
7. ANRS switch 24. Left microphone jack [MIC-LEFT]
8. Tape counter 25. Right microphone jack [MIC-RIGHT]
9. Counter reset button 26. Battery check button (BATT CH ECK]
10. Pause button [PAUSE @ff ] 27. Left VU meter
11. Stop button [STOP Bf J 28. Right VU meter
12. Fast forward button [FF »P ] 29. VU meter check light SW [CHECK LIGHT]
13. Play back button [PLAY/RECP] 30. REC master volume [REC MASTER]
14. Record button [REC] 31. Metal for shoulder strap.
15. Rewind button [REW << ] 32. Right Record level [RIGHT LEVEL]
16. Headphone jack [PHONES] 33. Left Record level [LEFT LEVEL]
17. Headphone volume
No. 4151

KD-2A/B/C/E/J/U |
Main Parts Location
CON|APWN>
No. 4151
@Oe9eee
“OOOO ®
Fig. 2
Battery
contact
(+)
14.
Battery
contact
ass’y
(-)
15.
Motor ass’y 16.
REC.
AMP
circuit
board
17.
Magnet pulley ass’y 18.
Pinch roller arm ass’y 19.
Counter ass’y 20.
Push button (Pause) 21.
Push button (Stop) 22.
Push button (FF) 23.
Push button (Playback)
Push button (Record)
Push button (Rewind)
R/P head
Erase head
Steel ball
Supply disc ass’y
Take up disc ass’y
Motor circuit board
Muting circuit board
ANRS circuit board
Main amp circuit board
Power transformer
Note; The circuit board assemblies and cassette mechanism
in this model will not be available as spare parts.

| KD-2A/B/C/E/J/U
Main Parts Removing
This cassette deck which features a compact design and performance uses miniatures sized parts which are closely arranged.
Enclosure Assembly
Handle
Enclosure assembly
Battery cover Push the battery cover the direction of arrow
in illustration and remove it to back.
Bottom cover Remove 5 screws (3¢ 12mm) and 1 screw
(3¢ 14mm) fastening the bottom cover.
Top panel 1. Remove the bottom covers Q)
2. Remove 5 screws fastening the top panel.
3. Remove to pull out the left side of the top
panel and to open in front of the front panel
by your fingers.
Knobs Pull off Master knob
Record level knobs
Headphone volume knob
MIC/DIN input select knob...
When remove the bottom cover, can be
adjusted the semi-fixed resistors on the
main amp circuit board.
Screws 5 p.c.s = 3d, 10mm (blue)
When replace the top panel, do as same
as (3)
Screws 4 p.c.s. = 3¢, 16mm
When replace the VU meter and the pilot
lamp, must be removed the front panel.
1. Remove the bottom cover and the top panel
2. Remove 4 screws fastening the handles
3. Pull off in front the master knob and the
Record level knobs
4, Pull off in front the front panel.
No. 4151

KD-2A/B/C/E//U |
Electrical Parts
Level meter )
Meter bracket
®
Fig. 4
Electrical parts
Parts name
VU
meters
1.
Remove
the
front
panel.
Tapping
screws
=
3¢,
8mm
2.
Remove
2
screws
fastening
the
meter
bracket.
Pilot lamp . Remove the front panel and the VU meter
. Remove the push switches bracket.
. Remove the bushing of the pilot lamp from
the push switches bracket.
. Remove the pilot lamp from the bushing
ANRS
.
Remove
2
screws
fastening
the
ANRS
Tapping
screws
=
36,
8mm
(violet)
circuit
board
circuit
board.
.
Pull
off
the
left
side
it’s
board.
REC
amp
.
Remove
2
screws
fastening
the
lever
switch
Screws
=
2.6¢,
4mm
(violet)
circuit
board
bracket.
.
Pull
out
the
connector
from
main
amp
C.
Be
carefull
to
pull
off
the
connector,
board
to
direction
of
the
arrow
in
illustration.
slowly
and
holding
the
both
sides
of
it.
(Because
it
may
be
broken
which
the
plate
is
wide)
Main
amp
.
Remove
washers
and
nuts
of
the
variable
Remove
the
main
amp
circuit
board,
after
circuit
board
resistors.
(master
volume
and
2
REC
disconnecting
the
F.P.C.
volumes.)
.
Remove
2
screws fastening the
PIN jack
circuit
board
(left
side of
it)
. Remove
2 screws
fastening
the
shield
board
at
bottom.
Screws = 3¢, 8mm
No. 4151 nae

| KD-2A/B/C/E/J/U
Mechanical Parts
Mechanical . Remove 6 screws fastening the mechanical
ass'y ass’y.
. Remove the counter belt.
. Remove the connecting wires of heads, etc.
Motor . Remove 2 screws fastening the shield plate 1. When replace the motor, replace it’s
. Remove the capstan belt. circuit board as same. (because motor
. Remove 3 screws and 3 washers fastening and it’s circuit board are pair parts for
the motor. adjustment.)
. Remove 2 screws fastening the motor circuit 2. Be careful not to stain the capstan belt.
board.
. Disconnect the wires of motor circuit
board.
Flywheel
Pinch roller
arm ass’y
Take up disc
Supply disc
Note;
1. Don’t dirty, slipply and undue run-out the capstan belt and counter belt.
. Remove 2 screws fastening the flywheel Holder.
2. Remove the flywheel holder from the
mechanical chassis.
. Remove the capstan belt.
. Pull out the flywheel.
. Remove ‘’E” ring holding the pinch roller
arm ass’y.
. Remove spring on the arm ass‘y.
. Remove the cassette holder
. Remove the counter belt
. Remove “E” ring holding the take up disc.
. Pull off the disc from the shaft.
. Remove the cassette holder
. Remove “E” ring holding the supply disc.
. Pull off the disc from the shaft.
When replace the flywheel, don’t forget
to insert a nylon washer to it’s shaft.
2. Adjust height of the motor pulley, when the capstan belt connect to the flywheel from the motor pulley, so that it will
be parallel to the chassis.
3. When remove the screw (19), use the maching driver to the screw top groove.
ae eee
No. 4151

KD-2A/B/C/E/J/U
Main Adjustments
Electrical Adjustment
Equipment
and
measuring
instruments
used
for
adjustment.
AUDIO
Freq.
OSC
1.
V.T.V.M,
(measuring
AC
in
millivolt)
Se
—o
ATTENUATOR
2.
Audio-frequency
oscillator
\
Sy
%
aa
(range:
50—20kHz
and
output
OdBs
with
impedance
6002
)
i
-
&
ASS
dA,
‘|e
3
600
3.
Attenuator
(6002
)
i
LG
oun)
4.
Reference
tapes
for
REC/PB
Il
"
pre
TS-1
(OP-12,
C521V)
—
normal
tape
Nap
eel
<a
TS-2
(TP-18,
C402R)
—
chrome
tape
ouTaUT
LINE
a
LINE
OUT
5. Reference tapes for playback
VTT-658 (for head adzimuth)
VTT-656 (for tape speed & wow flutter)
VTT-664 (1kHz reference level)
VTT-675N (for playback frequency response)
6. Resistors
1002 (for measurement of the bias current)
6002 (for attenuator matching)
7. Distortion Meter, Band pass filter
When
you
adjust
following
items,
we
recommend
to
you
to
keep
doing
step
No.
1. Electrical Adjustment
Playback
1.
Level
meter
.
Set
the
deck
to
the
record
mode.
|
Main
amp
The
angle
of
meter
deflection
has
deflection
;
Input
1kHz
signal
(about
10dBs)
|
circuit
board
been
factory-adjusted,
but
should
from
LINE
IN
jacks.
be
adjusted
when
parts
are
.
Adjust the
REC volume
so
that
replaced.
LINE OUT
become
3.5dBs.
.
Adjust
R148
and
R248
in this R148,
248
VU
meter
condition
it
obtain
zero
VU
(METER)
range;
O
meter
reading
.
Playback
.
Set
equalizer
switch
at
Main
amp
.
Should
be
adjusted
playback
sensitivity
“NORMAL”
position
and
turn
circuit
board
sensitivity
when
heads
are
off
ANRS
switch.
replaced.
. Adjust R126 and R226 so that R126, 226 VU meter | 2. Make this adjustment after
level meters indicate zero VU (P.B LEVEL) range; 0 making sure level meter deflec-
using reference tape VTT-664 tion angle is correct.
(1kHz)
.
Check
of
PB
Playback
the
reference
tape
VTT-
i
.
When
use
reference
tape
VTT-
frequency
675N
(1kHz)
and
check
the
OUT
675,
it’s
level
over
about
3~4
response
PUT
level
of
bach
frequency
to
Reference
frequency;
1kHz
dB
at
63Hz
compared
with
become the rating. Normal 63Hz +2dBt3dB 1kHz.
10kHz O +3dB/ 2, When check at chrome it’s
Chrome 63Hz +2dB+3dB level, set the equalizer switch
10kHz ~-4dB+3dB at “NORMAL” position to
compared with 1kHz.
Record/playback
TS-1
use
at
normal
mode
and
TS-2
use
at
chrome
mode.
1.
Check
of
REC/
|
Input
1kHz
(OVU-20dB)
signal
Reference
frequency;
1kHz
j
Do
adjust
normal
and
chrome,
from LINE IN make recording the
PB
frequency
blank
tape,
and
then
record
50Hz,
Normal
50Hz
O+3dB
|
Lchannel
and
R
channel.
response 10kHz signals. 10kHz O0+3dB
When it’s Ape playback, 50Hz or Chrome 50Hz 0+3dB
10kHz output level become in ratin
at comparison 1KHz output level ae. 1OkHz O+3dB
the reference frequency.
(As basic thought, 1KHz, 50Hz and
10KHz output level become the flat
frequency responce as same.)
No. 4151 22°8, =

Procedure
2. Bias current
3. REC/PB level
. Check of
REC/PB
distortion
. Check of
REC/PB signal
to noise ratio.
. Check of
erasure ratio
Input 1kHz and 10kHz (OVU—20dB)] Rec amp
signals from LINE IN to record in
reference tape.
When playback it’s tape, adjust R
R514, 614 (normal) and R513, 613
(chrome) so that OUT PUT levels
become equal values.
R/P HEAD
[Easy method]
. Set the deck to record mode.
. Connect a 1002 resistor to the
ground side (at record mode) of
the head wire.
. Measure it’s voltage.
. Input 1kHz (-10dBs) signal from
LINE IN, adjust the REC master
volume so that LINE OUT level
become —8dBs.
. Make recording in such a way
that the level meters indicate
zero VU at normal mode or
chrome mode (as same Left
channel or right channel)
. Playback it and adjust the semi-
fixed resistors for REC level so
that the level meters indicate
zero VU.
. Input 1kHz (-10dBs) signal
from LINE IN, and make re-
cording in such a way that the
level meters indicate zero VU.
. Playback and check it that the
distortion become rating less.
. Input 1kHz OVU signal from
MIC IN, make recording that
the level meters indicate zero
VU, and then make recording at
no signal mode.
. Playback it’s tape and measure
the signal to noise ratio by
V.T.V.M.
. Input and make recording as
same 5.
. Continue recording to up 20dB
the signal level.
. Rewind it’s tape and erase the
part of it.
. Measure output level to the re-
cording part ratio the erasing
part.
circuit board
Normal
R514, 614
(BIAS)
Chrome
(BIAS)
Normal
33mV
Chrome
53mV
Main amp
circuit board
Normal
[R149, 249
REC LEVEL]
Chrome
[R150, 250
REC LEVEL]
Normal
3% less
Chrome
4% less
Normal
| KD-2A/B/C/E/J/U
Remarks
. Standard method for bias
adjustment of cassette deck
are adjusted the frequency
response at REC/PB. Be-
cause the cassette tape is
great affection to bias cur-
rent of frequency responce
than open-reel tape. When
you measure the bias curr
rent, can you doing the
easy way as below.
. If not correct the bias cur-
rent, frequency responses are
shown as the next figure.
too fow
most
switable
too high
KHz 1OKH 2
. If the meter pointer moving
at PB mode when your finger
touch a head wire, it’s wire
is ground side at Rec mode
(Because the head wire of 2
head deck become opposite
polarity at playback and at
cords)
4. Must use the shield wire.
cw Response(dB)
The difference in level of
each channel is less than 1dB.
Make this adjustment after
making sure bias current, and
REC level.
REC volume at maximum.
42dB or more
more
Chrome
42dB or
more
When measure the erasing ratio,
connect the B.P.F (Band pass
filter) to the deck from the
V.T.V.M. (mitivolts)
No. 4151

KD-2A/B/C/E/J/U
Item Procedure
7.
ANRS
.
Disconnect
the
soldering
position
|
ANRS
circuit
circuit
BIAS
CUT
of
main
circuit
board
so
that
osillator
does
not
operate.
. Set the deck to the record mode.
. Input 1kHz -10dBs signal from
LINE IN, Adjust the REC
volume so that LINE OUT be-
come —-0.5dBs. (not move the
REC volume position to
finished adjustment.)
. Turn R335, 435 (CONT GAIN)
and R340, 440 (DC BIAS) in
the direction opposite to the
arrow marking in the shield board.
. Adjust R324 and R424 so that R324, 424
level does not change when (REC GAIN)
ANRS switch is turned on and
off, and turn on ANRS.
. Input 1kHz -50dBs signal from R340, 440
LINE IN, Adjust R350 and (DC BIAS)
440 so that LINE OUT become
—35dBs.
. Input 5kHz -30dBs signal from R335, 435
LINE IN Adjust R335, 435 so (CONT GAIN)
that LINE OUT become 17dB.
. Repeat step (5) through (7).
. Turn ANRS switch in ‘‘Super’’
position when input 10kHz
-10dBs signal from LINE IN.
Check out put levels are
~6.5dBst2dB.
. Connect the position BIAS CUT
of disconected in step (1)
-
.
Playback
reference
tape
VTT-
R302,
402
664
and
Adjust
R302
and
R402
‘|
(PB
GAIN)
so
that
level
does
not
change
when
ANRS
is
turned
on
and
off.
Other adjustments
Procedure
Remarks
1.
Battery
1.
Apply
exactly
DC3.8V
to
ex-
Do
not
mistake
one
polarity
for
checker
ternal
DC
jack
or
battery
contacts
the
other.
and
switch
the
deck
to
playback
or
fast
forward
mode.
.
Push
battery
check
switch
in
“CHECK”
position
and
adjust
so
that
meter
pointer
deflects
to
the
end
of
green
area.
.
Check
of
Apply
exactly
DC
6.0V
to
external
Play
back
Standard
Pilot
lamp
at
OFF
no
signal
power
con-
DC
jack
or
battery
contacts
and
200mA
or
less
165mV
Do
not
insert
cassette
tape
sumption
switch
the
deck
to
playback
or
Record
300mA
{Standard
record mode. or less ( 240mA )
Measure the consumption current
as a such way by miliampere meter.
No. 4151 240° 2

Adjustments position location
This deck can be adjusted to remove only the bottom cover.
®
BATT. CHECK LEVEL
L R
bm
° law
ae 9
B. LEVEL——
&) F.W. THRUST
L R
ry REC. LEVEL
le CrO. NORM
L___werer _ 8s Te ee
oN NN
CN)
Lb RL
C. Or
Cr. Or
onus ©
CrO,
CONT. GAIN
C)
CONT. GAIN
S-n00.can-@
eo ve, aas—_“%
Fig. 7
Repair of electrical parts
1. Flexible printed circuit board
This model is used the flexible p.c. board to connection
the circuit board.
Because it is earsy repair for servicing and earsy produc-
tion for factory.
It have good quality for hardy or other condition, but be
careful following items.
(1) As it’s board increase the humidity compare with
normal circuit board, after place it in high humidity,
if do you solder it that may be broken the print.
(2) If do you scratch it by cutter etc., may be broken it.
(If not scratch, it is very hardy board.)
(3) Do not fold with sharp angle (an acute angle)
(4) Don’t solder on the flexible area.
(If solder, it may be broken near soldering position
as illustration.)
If you repair to broken the pattern.on F.P.C. board,
connect to solder with wire between the circuit
board(1) and circuit board(2).
2. For other electrical failures, check the unit in the same
manner as other cassette decks.
NORM
Circut board (1)
Circuit board (2)
| KD-2A/B/C/E/J/U
Direction of arrow marks
B|IAS=bias current increase
ANRS=ANRS signal level up
PB LEVEL See
REC LEVEL See
METER eitiesiens
BATT. CHECK LEVEL { ~ “flection increase
MOTOR SPEED = speed up
F.W. THRUST = clearance narrow
(Look with a bond, after adjust the F.W,
THRUST)
Flexible
Printed circuit board
Discorrect
as soldering
Fig. 8
No. 4151

KD-2A/B/C/E/J/U
Mechanical Adjustment
Height of E head
Head position
check
Procedure
Part
Rating
Remarks
REC/PB
head
1.
Connect
the
milivolt
meter
to
.
If
either
of
the
REC/PB
head
azimuth
inclina-
LINE
OUT
jacks.
(or
REC/PB
show
low
performance
be-
socket)
cause
of
wear,
broken
wire
or
2.
Playback
the
reference
tape
VTT-
oxcessive
magnetization,
it
658
(10kHz).
should
be
replaced,
and
then
3.
Turn
the
screw
B
so
that
mili-
you
must
adjust
the
head
volt
meter
indicate
maximum
azimuth,
playback
sensitivity,
(output
level
become
max.)
REC
bias
current,
and
REC/PB
4.
After
adjustment,
the
screw
Screw
B
Max.
level
(see
electrical
adjust-
ment.)
2. If Land R channel levels of
head become unbalance 3~4
dB or more, you should be
replaced the head.
B should be locked with a
bond.
When replace the E head, must
be adjusted this method.
Playback the test tape C-120 (front
cutted cassette) and turn the screw
D so that the tape may run in the
center of the guide.
1. If the tape touch the upper
guide, loose the screw D
~<——- Tape guide (upper side)
— Tape
2. If the tape touch the low guide,
fasten the screw D
Sg Tape
~=«—— Tape guide (low side)
After adjustment, the screw D
should be locked with a bond.
Check the head position by the gaze.
The clearance is 0.7mm or less
between the head and the gaze.
. Check with your own eyes.
2. If not, high frequency range
or erase ratio will be down.
0.7 mm
or less
Motor speed
3000Hz
42%
(2940~
3060Hz)
. Motor current is 100mA at
playback.
2. If the wow flutter meter
built-in the counter meter,
connect it’s INPUT jacks.
1. Connect the counter meter to
the LINE OUT jacks.
2. Playback reference tape VTT-
656 (3000H2z).
3. Adjust the semi-fixed resistor on
the motor circuit board so that
the speed is 3000Hz+2%
Take-up torque
(if not)
1. Clean the main belt, rubber
rim of idler and rubber rim of
the Take up disc.
2. Replace the idler arm of the
take-up and spring.
Measure by the torque measure
cassette or the torque gaze tool
at the playback mode.
Fast forward
torque
(If not)
1. Clean the main belt, rubber
rim of the idler, motor pulley
rim of the flywheel.
2. Replace the main belt, idler,
and reel disc ass’y.
70 gr-cm
or more
Measure as same way at FF mode.
No. 4151

| KD-2A/B/C/E/J/U
Procedure Remarks
REW torque Measure as same way at REW 70 gr-cm | (If not)
mode. or more 1, Clean the main belt, idler and
rubber rim of it, and motor
pulley, rim of the flywheel
. Replace the reel disc.
Auto-stop Loosen 2 screws fastening the Check if the locking and sliding
mechanism solenoid and move it position parts of the operation button
for adjustment. cam are well coated with molyb-
denum.
Repair of Wow Flutter
{f wow and flutter increase, check the following points.
If there is defect in revolving parts, the wow and flutter
generated will increase in proportion to the number of
revolutions.
Play a 3000Hz test tape, and defective part can be detected
from the sound.
ee
Capstan and Capstan shaft has excessive run-out.
flywheel Flywheel turns heavily.
(shaft seisure, thrust play, etc.)
Replace flywheel.
Clean the capstan shaft and the groove in the
flywheel.
Apply oil to the metal position.
Replace the capstan assembly.
Replace pinch roller, or pinch roller spring.
Clean the pinch roiler or apply oi! to the rotary
shaft.
Adjust the pinch roller so that it is parallel with
the capstan shaft.
Replace the pinch roller spring.
Rough rotation (Deformation
scratches, or dust).
The angular position of the pinch
roller is not correct.
The pinch roller pressure is not correct.
Pinch roller
Clean the belt.
Replace the belt.
Belt has undue run-out.
Belt is dirty or slippery.
Replace back tension spring (under supply disc).
Back tension is irregular, or back
tension is too strong.
Back tension
Replace motor.
Clean motor pulley.
Motor shaft has undue run-out.
Motor pulley is oily and dusty.
Pulley has deflection. Replace take-up idler arm.
Pulley is stuck.
Take-up idler arm
No. 4151
a ee

No. 4151
KD-2A/B/C/E/J/U |
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) Press the PLAY button to move the heads out.
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
1) Press the PLAY button, and the pinch roller will
move out and rotate.
2) Apply a soft cloth (soaked in alcohol, it will be more
effective) to the rotating pinch roller and capstan.
Be careful not to let the cloth get caught!
* Do not use any cleaner besides alcohol or a spe-
cifically prepared tape head cleaning solution.
la
a
a “
(, =e
Soft cloth
Direction of rotation
N of pinch roller
Pinch roller oN
(2)
(o)
Capstan
Fig. 9
3. Cabinet
When the cabinet becomes dirty, wipe it with a soft
cloth soaked with a neutral cleaning solution of a polish-
ing cloth.
Do not use thinner or benzine.
Demagnetizing
The heads are made from a material resistant to magnetiza-
tion, 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 if off
at a distance of more than 30cm. (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.
Oiling
Feed one or two drops of machine oil to the rewind roller
shaft, pinch roller shaft and magnet pully shaft once or
twice a year under normal conditions of use.
Avoid oiling them excessively, or rotation may become
irregular because of oil splashes.
944

| KD-2A/B/C/E/J/U
Block Diagram
TA7066P Equivalent Circuit
+83
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HEAD AMP ANRS CIRCUIT i
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+80
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REC LEVEL
7 BIAS ADJ
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oe
(Bottom-view)
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RECIPB
HEAD
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(MIC/DIN
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STOP(FF,REW)2=pg
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SW
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PAUSE PB(FF, REW) AL_o ;
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2SA721
$102
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INPUT
SELECT(MIC/DIN)
$904-1V-2
MUTE
(STOP)
SIGNAL
LINE
B
Base
2SC
1327
S50Il
-IV-2
BIAS
(Cro2)
$905
BATT
CHECK
(OFF)
POWER
SUPPLY
LINE
C
Collector
2SC828
2SC828A
$502-I-~-2
ANRS
(OFF)
$906
LAMP
(OFF)
i
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$503-IV-3
EQ
(cro2)
$907
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SWITCH
2SD545
$901 POWER (STOP/OFF) $908 AC SOCKET (OUT)
Base
Collector 2SC 1847
Emitor
|
2
3
: TA7066P
6
7
Fig. 10
-— 15 — No. 4151

| KD-2A/B/C/E/J/U
Circuit Boa rd Parts Red print is shown the voltage (V) of playback mode (_ ) voltage: to use 20k2/V impedance tester.
Main Amp Circuit Board
—
L,
Loh Playback Level Adj Rch Playback Level Adj
E oe : ‘iss :
eae
Fe
Sa
SS Gag f°] 0006 te
Mo ei 1.
4
eos
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a
She
pa ts
ores
<
$87 rey 1p
Lae
Bias Cut
Open this soldering
position at Bias adjustment
Roh Meter Gai
#Bych Meter Gain Adj
+ D90}
a
seo ice —— <_
/ mm x a | : ‘
Fig. 11
No. 4151 = HBS

| KD-2A/B/C/E/J/U
Main Amp Circuit Baord Parts List
*TAA336105-02 Circuit Board Not supplied as parts Ass’y
QSS9201-001 Slide Switch
*TAS350402-01 Shield Plate
*TFB336401-01 Switch Connector
SPSP2006Z Screw
R121,221 *QVC4A2A-054X V. Resistor Master REC 5OKQ? (A)
R120,220 *QVG4A2B-054 ” Sub. REC 5OKQ (B)
*QMS6311-001 Jack Ass’y R-CH Mic
*QMS6313-001 L-CH Mic
*QMS6302-104 Headphone
*TAJ000345-01 LINE & DIN
*QSR5743-300 Rotary Switch Input Select
R152,252 *QVD7A2C-0F2 V. Resistor H. P. Level 2502 (C)
*TFB336312-01 Jack Bracket
SPBP3008BS Screw
*TAZ336499-01 Volume Lug
*TAZ336499-02 "
OMC0627-001 ”
*QMV2001-101 Socket Ass’y
E43727-003 Lapping Pin
(REC/PB Amp)
R101,201 ORD142K-122 C. Resistor
R102,202,116,216 QRD143K-102
R 102,202,114,214 QRD143K-103
R104,204 ORD143K-122
R105,205 ORD141K-823
R 106,206,107,207 QRZ0019-104 (Low Noise)
R 108,208 QRD143K-394
R 109,209 QRD143K-564
R110,210 QRZ0019-393 (Low Noise)
Ri11,211 ORD143K-391
R112,212,115,215 ORD143K-121
R113,213 QRD143K-184
R117,217 ORD143K-104
Ri18,218 QRD143K-332
R119,219 QRD143K-333
Ri25,225 QRD143K-821
R126,226 QVP8A0B-054 V. Resistor
R127,227 QRD143K-473 C. Resistor
R128,228 ORD143K-224 ”
R129,229 QRD142K-102 ”
R130,230 QRD143K-394
R131,231 ORD143K-823
R 132,232,137,237 ORD144K-222
R 133 ORD143K-331
R332 ORD142K-331
R134,234 QRD143K-822
R135,235 ORD142K-272
R136 143, 243 QRD143K-123
Roz6
QRD142K-123
R138,238,140,240 QRD142K-473
Haagiesa QRD142K-471
Praia ORD142K-472
Ria2 ORD143K-181
Roao QRD142K-181
Riaaoaa ORD143K-473
Q
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_a- No. 4151

KD-2A/B/C/E/J/U
2
a
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Part No. Part Name
R
145,245
ORD143K-473
C.
Resistor
Bae
oa
ORD143K-472
eee
ORD143K-561
R448,248
QVP8A0B-013
R
149,249,150,250
OVP8A0B-014
R451,251
QRD142K-223
22KQ
R1i52,252
QRD142K-472
47KQ
Rass
QRD142K-333
33K
2
Rosa
QRD142K-562
5.6KQ
C401,201
QCY41HK-272
C.
Capacitor
2700PF
C 102,202 QEE41EM-475 E. Capacitor (Tantal)
C 103,203 OEB41EM-106 vy (Low Leak)
C 104,204 OCS11HK-331 Fixed C. Capacitor
C 105,205 acs 1 HK-471 ae
C 106,206 QEB41EM-476M E. Capacitor (Low Leak)
C107,207 QCS11HK-470 Fixed C. Capacitor
C108,208,113,213 QEB41EM-105 E. Caapcitor
C
109,209
QEW41AA-107
”
C1410,210 QFM41HJ-273 Mylar Capacitor
C441,211 QEW41EA-476 E. Capacitor
C412,212
QFM41HJ-103
Mylar
Capacitor
C414,214
QEW41CA-106
E.
Capacitor
C115,215
QCS11HJ-820
Fixed
C.
Capacitor
C116,216
QFM41HJ-222
Mylar
Capacitor
C417,217
QEW41AA-476
E.
Capacitor
C118,218 QEW41EA-475
C119,219 QEW41EA-336
C420,220,124,224
QEW41EA-106
C121,221 QFM41HK-102 Mylar Capacitor
C1422,222 QEW41EA-476 E. Capacitor
C123,223
QEB41HM-334M
(Low
Leak)
C
125,225
QEW41EA-475
C
126,226
QEW41CA-106
C
127,227
QEW41EA-105
C
128,228,129,229
OCR11HK-561
QCS11HK-101
L101,201
TAC000324-05
Inductor
L
102,202
TAC000493-01
”
T 401,201 T44944-001 Headphone transformer
D101,201,102,202
IC 401,201
X101,201
X102,202,104,204
X103,203,105,205,
106,206
(Power Supply)
R905
18188AM
TA7066P (B)
2SA721 (TU)
28C1327 (TU)
3SC828 (RS)
QRD121K-121
Diode
IC
Transistor
”
m"
C. Resistor
Roos
Cg07,908
Coag
Coi0
Coi1
QRD142K-330
OCF 12HP-103
QEW41CA-108
QEW41AA-477
QEW41AA-227
Dg904,905,906,907
ZDgq2
Xgo3
No. 4151
T30155-001
RD6.2F (B)
*2SC1847 (R)
TAR336498-01
DPSP30082ZS
"
Fixed C. Capacitor
E. Capacitor
”
uo
Diode
Zener Diode
Transistor
Radiation Plate
Screw
—~ 18 —

[retne [Pare
(DC-DC Converter)
Rgo1
Rgo2
Rgo3
T9014
Doo
Dgo2
Dgo3,904
ZDg01
(Auto Stop & Muting)
Dgog
Dg40,911,912
X905
X906
X907
TAA336496-01
ORD143K-561
ORD143K-681
ORD143K-220
QEW41AA-107
QEW41AA-227
QFM41HK-153
QCS11HK-391
QEW41EA-476
QEW41EA-477
QEW41CA-476
QEW41CA-477
QRD143K-680
*TAC000344-01
*TAC000346-01
*TAZ2271302-01
MA162
MA161
MA150
RD22E (1)
2SC828 (R)
*2SC1847 (R)
*TAS336477-01
*TAS336478-01
*TAD336497-01
*E43727-003
QRD143K-393
QRD143K-124
ORD143K-101
QRD143K-101
ORD 143K-104
ORD143K-333
ORD143K-100
QRD143K-682
ORD143K-332
QRD143K-562
QRD143K-823
ORD142K-333
QRD143K-102
QRD143K-471
QRD143K-122
QEB41EM-106
QEW41EA-107
QEB41HM-474M
QEW41AA-227M
QCF11HP-103
QEW41AA-476
QEW41EA-105
QEW41EA-335
2SF656
T30155-001
MA150
2SA564A (RS)
2SC828 (RS)
2SC828A (RS)
Part Name
Remarks
KD-2A/B/C/E/J/U
Circuit Board
C. Resistor
"
”
E. Capacitor
Mylar Capacitor
Fixed C. Capacitor
E. Capacitor
.
C. Resistor
Inductor
”
Converter Transformer
Diode
Zener Diode
Transistor
wn
Converter Case (A)
o (B)
Insulator
Lapping Pin
C. Resistor
E. Capacitor (Low Leak)
”
Fixed C. Capacitor
E. Capacitor
m”
Diode
mw
Transistor
"
”
= 4.91
Not supplied as parts ass‘y
56022
68022
220
100uF
= = oo
No. 4151

KD-2A/B/C/E/J/U
REC Amp Circuit Board
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Circuit
Board
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Fig. 12
No. 4151
— 20 —-