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