Kenwood KX-4520 User manual

| SERV. 29H
YZ
STEREO
CASSETTE
DECK
Knob(EJECT)
(K29-3807-04)
Knob (POWER)
{K29-3805-04)
Foot
KX-4520
SERVICE
MANUAL
Cassette lid ass’y
(A53-)
GTENEG GASMITTE DESK Kx-a5R0
Dressing plate
(B50-)
(JO2-
1002-05)
x
Phono jack
(E13-0482-05)
|
04
KENWOOD
©1989-10
PRINTED
IN
JAPAN
B51-3904-00(B)3301
-
Knob (REC LEVEL)
(K29-3804-04)
* Panel ass’y
(A20-5919-03)
Remote control ass’y
is
Knob
(A70-03
17-05)
(K27-2003-04) x3
* AC inlet (M type only)
(E03-0102-25)
cso ORE aR ek
sem meacseN
Miniature phone (SYSTEM CONTROL)
(E11-0188-05)
*Refer
to
parts
list
on
page
42.

KX-4520
CONTENTS
CONTROL
AND
INDICATORS.........---------+-555
2
PC
BOARD
(Component
Side
View)
DISASSEMBLY
FOR
REPAIR.....-.-.-----++--
+2005
3
PC
BOARD
(Foil
Side
View)
........
BLOCK
LEVEL
DIAGRAM........-.--..-
2-02
e
sree
eee
5
SCHEMATIC
DIAGRAM
........-..--
CIRCUIT
DESCRIPTION
........---.
02.
eee
eee
renee
6
EXPLODED
VIEW
(MECHANISM)...
MECHANISM
DESCRIPTION.........-.----.--
eee
ee
20
EXPLODED
VIEW
(UNIT)
.........-.
ADJUSTMENT
........2
00
e
cece
cece
enter
eens
22
PARTS
LIST
........
002
eee
eee
ee
eee
REGLAGE
225.08
Soe
et
B
ot
eSNG
heme
Lee
Yee
23
SPECIFICATIONS
.......-.--.--005>
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24
CONTROL
AND
INDICATORS
TAPE/SOURCE indicators
1 ‘
AUTO BIAS indicator PEAK LEVEL METER
Operation indicators
SNTERT! DOLBY 7
ray GOUNTER 1) OMBY |
ip
me
so
2015
10
7
SB
2
1
0
1
FS
7
OB
1 OO ence,
Tape position indicators
DOLBY NR indicators
Display window
MULTLWAY COUNTER
CCAS key —~\
COUNTER RESET key
AUTO BIAS key
Eject
key
TAPE/SOURCE
selector
(MONITOR)
key
REC/ARM PAUSE key
PAUSE key fi
REC LEVEL control knob
Remote contro!
light receptor
REC BALANCE
control knob
PHONES LEVEL
control knob
PHONES jack
Cassette holder
Rewind key Te}
TIMER
switch
Fast
forward
key
[>>)
Play key
co
POWER switch
MPX FILTER switch
Stop k
op
ney
DOLBY
NR
switches
ON/OFF switch
B/C selector switch
Note on counter’s preciseness
The Jinear tape counter used with this unit is not a
clock, and there is a certain error between the
displayed time and real recording time {this is un-
avoidable because this unit has been designed to be
capable of displaying tape time also during fast
forward and rewind operations as well as during
recording and playback). The degree of this error is
dependent on the type of tape.

om
“* Take out the case in advance.
1.
2.
ONOARW
9.
10. Remove the three screws @.
11.
Undo
the
four
catches
()
.
and
disconnect
the
board.
KX-4520
BLOCK LEVEL DIAGRAM
Remove the five screws :
Undo the three catches , and detach the front pan-
el.
Remove the three knobs and two nuts @.
Remove the two screws @.
Cut the two convexes eS :
Disconnect the eight connectors 6) .
Unground @.
Undo the two catches at the both sides, and detach
the sub panel ©.
Remove
the
two
screws
@
.
and
detach
the
shield
plate.

KX-4520
DISASSEMBLY
FOR
REPAIR
12.
Press
the
eject
button
to
open
the
cassette
holder
@.
13.
Setaside
the
eject
lever
to
the
left
side
®.
(When
detaching,
draw
it
out
in
the
upper
left
direc-
tion)
14.
Remove
the
four
screws
@
.
and
take
out
the
mecha-
nism.
15.
Disconnect
the
board
(X26)
(B/2)
®.
16.
Remove
the
seven
screws
;
17.
Disconnect
the
connector
.
18.
Draw
up
the
board
together
with
the
rear
panel
rear-
wards.
19.
When
detaching
the
knob
of
the
power
switch,
open
slightly
the
portion
indicated
by
arrows
using
a
lead
punch,
etc.

KX-4520
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KX-4520
CIRCUIT DESCRIPTION
Description of component
Cassette unit (X26-1240-00)
Use/function Operation/condition/compatibility
28C1740S
(Q,
R)
Playback
EQ
time
constant
Selects
between
120
psec
and
70
usec
of
playback
EQ
high-frequency
time
constants!
2SC945 (A) (Q, P selection switch
nee i [tape _[an.2 | Tine constant |
Normal 3180~120 (psec)
Chrome 3180~ 70 (usec)
Metal 3180~ 70 (usec)
2SC2878
(B)
Line
mute
switch
For
recording
or
playing
source,
the
pin
10
(LM)
of
microprocessor
1C12
becomes
“H”
2SD1302
(S,
T)
and
044
thereby
turns
OFF
so
that
03
and
Q4
turn
OFF.
REC - PLAY - SOURCE
OTHER
2SC1740S
(Q,
R)
MPxX
filter
switch
An
“H"
or
“L”
signal
is
output
according
to
the
“ON”
or
“OFF”
operation
of
the
MPX
2SC945
(A)
(Q,
P)
filter
switch
(S1-C/3:
X25-3770
system) so
that Q5~Q8
turn
ON or
OFF. When
Q5~Q8 turn ON,
the
MPX
filter
works.
2SC2878
(B)
Recording
mute
switch
For
recording,
the
pin
171
(RM)
of
microprocessor
1C12
becomes
“H”
and
Q43
thereby
2SD1302
(S, T)
turns
OFF
so
that Q9~Q12
turn OFF.
Q13,
14
2SC1740S
(Q,
R)
Recording
EQ
chrome
switch
When
a
chrome
tape
is
loaded,
the
pin
10
(C)
of
extension
IC
1C13
becomes
“L”
and
2SC945
(A)
(Q,
P)
Q32
thereby
turns ON
so
that
Q13
and
Q14
turn
ON.
Q15, 16 2SC1740S (Q, R) Recording EQ metal switch
2SC945 (A) (Q, P)
Q17,
18
2S8C17408S
(Q,
R)
Recording
EQ
peaking
selection
When
a
normal
tape
is
loaded,
the
pin
11
(N)
of
extension
IC
IC13
becomes
“L"
and
2SC945
(A)
(Q,
P}
switch
Q31
thereby
turns
ON,
while
when
a
chrome
tape
is
loaded
Q32
turns
ON
in
the
same
process,
so
that,
either
way,
Q17
and
Q18
turn
ON through
a
diode
matrix
D5
Q19
2SC1740S
(Q,
R)
Test
signal
mute
switch
For
AUTO
BIAS
operation,
the
pin
5
(O/L)
of
extension
IC
1C13
becomes
"L”
and
Q19
2SC945
(A)
(Q,
P)
thereby
turns
OFF
to
pass
the
test
signal.
i
Except
for
AUTO
BIAS
operation,
Q19
is
ON.
Q20,
21
2SC1740S
(Q,
R)
Test
signal
filter
cutoff
frequency
For
AUTO
BIAS
operation,
selects
between
cutoff
frequencies
in
synchronization
with
2SC945
(A)
(Q,
P)
selection
switch
the test
signal
frequency.
Fraguenc
400/10k
IC13
Fenuency
pin
6
Except
for
AUTO
BIAS
operation,
Q20
and
Q21
are OFF.
2SD863
(E,
F)
Erase
head
excitation
For
recording,
a
push-pull
oscillation
is
made
at
f=210
kHz
to
flow
the
erase
current
and
the
bias
current.
28C3246
BIAS+B
ON/OFF
switch
For
recording,
the
pin
25
(BIAS)
of
microprocessor
|C12
becomes
“H”
and
Q30
thereby
;
turns
OFF
and
Q25
OFF
so
that
Q24
turns
ON
to
apply
+B
to
the erase
oscillator
and
the
HX
excitation
coil.
025 | ass | az24
OFF | OFF ON
ON ON OFF
o
DTC124ES
Bias
ON/OFF
switch
For
recording,
Q25
turns
OFF
to
let
the
bias
ON.
aa

Name
DTA124ES
ne RISER Orne TELS MRO aE OREO SS SRST TY DTC
~KX-4520
CIRCUIT DESCRIPTION
Use/function
Operation/condition/compatibility
Bias step driver
For AUTO BIAS operation, the bias current is varied to correct the tape
recording/playback frequency response. (MAX. 16 steps)
Due to the “H’/"L” action of the pins 1~4 (B1~B4)} of extension IC 1C13, transistors
Q26~Q29 turn OFF/ON so that the transistor of IC8 turn OFF/ON to vary the bias
current.
Extension IC (1C13) Driver ATT switch (IC8)
B4 (P4): H/L Q29: OF/ON INVERTER 1: OFF/ON
B3 (P3): H/L Q28: OF/ON INVERTER 2: OFF/ON
B2 (P2): H/L Q27: OF/ON "INVERTER 3: OFF/ON
Bi (P1): H/L Q26: OF/ON INVERTER 4: OFF/ON
Initial value B4—"L" Q29=ON INVERTER 1=ON
B1~3=—="H" Q26~28-OFF INVERTER 2~4—OFF
oe
Q30 2SA733 (A) (Q, P) Bias ON/OFF driver
2SA933S (Q, R)
Q31~33
034, 36
DTA124ES
DTA124ES
DTA124ES
DTA124ES
Refer to the pertinent description under Q24.
Tape selector driver
DOLBY NR mode selection switch
Tape/source selection control
DTC124ES
Extension IC (IC12)
N (pin 11) | C (pin 10) | M (pin 9) Q31
Normal H H ON
Chrome L H OFF
Metal H OFF
Due to the “H"/"L" action of pins 11 (N), 10 (C) or 9 (M) of extension IC IC13
depending upon the tape loaded on the deck, the tape selector driver's Q31, Q32 or
Q33 turns ON for a normal, chrome or metal tape, respectively.
To provide the DOLBY noise reduction mode selected by the DOLBY NR ON/OFF and
B/C switches (S1-a/3, b/3: X25-3770 system), due to the “H"/*L" action of the pin 8
(DOLBY ON/OFF) of extension IC IC13, Q36 and 037 turn OFF/ON, while due to the
“H"/“L" action of the pin 7 (DOLBY C/B), Q34 and Q35 turn OFF/ON. Thus, the
DOLBY noise reduction mode is determined by "H’/“L” combination.
poisy | powey on/OFF | ooieye7S [ase | axe [ae [oar
OFF L L OFF | OFF | ON | ON
B H L OFF | OFF | OFF | OFF
c H H ON | ON | OFF | OFF
Due to the “L"/"H" action of the pin 9 (T/S) of extension IC IC13, Q38 and Q39 turn
ON/OFF to apply an “H’/"L” signal to the control pin of monitor selection analog
switch IC3.
MODE
T/s
038 039
IC3
Pins.12
and
13
of
IC3
TAPE
L
ON
ON
BV
sv
SOURCE
H
OFF
OFF
-8V
BV
Q40
25C1740S (Q, R)
Meter amplifier gain selection
switch
{
For AUTO BIAS operation, Q40 turns ON to raise the meter amplifier R-ch gain. The
AUTO BIAS test signal (—20 VU) is thus amplified for easier microprocessor level
discrimination. Except for AUTO BIAS operation, Q40 is OFF.
2SC945 (A) (Q, P)
Q41
DAT124ES
Test signal/line signal selection
driver
For AUTO BIAS operation, the pin 5 (O/L) of extension IC IC13 becomes “L” so that
Q41 goes ON to turn 040 and 042 ON.
on | aa | aso | aaz
AUTO BIAS L ON ON ON
OTHER H OFF OFF OFF
ye? ee a
Q43
DTC124ES
Test signal selection switch
To pass the test signal in AUTO BIAS operation for recording DOLBY IC IC4, Q42
turns ON to select an input line.
2SA733 (A) (Q, P)
2SA933 (Q, R)
Recording mute drive
Controlled by the output of the pin 11 (RM) of microprocessor IC12. Also refer to the
pertinent description under Q9~Q12.
aaa
————|-284733(A)
(Q,
P)
2SA933 (Q, R)
Line mute drive
Controlled by the output of the pin 10 (LM) of microprocessor IC12. Also refer to the
pertinent description under Q3 and Q4.

KX-4520
2SC1740S (Q, R)
2SC945 (A) (Q, P)
CIRCUIT DESCRIPTION
Use/function Operation/condition/compatibility
At POWER ON/OFF, apply “L” to the pin 27 (RESET) of microprocessor 1C12 and the
pin 16 (RST) of extension IC IC13 to reset.
Microprocessor reset
Right after
POWER ON POWER OFF
ON OFF
OFF after a fixed } OFF after a fixed
time of ON time of ON
Right after
2SC17408 (Q, R)
2SC945 (A) (Q, P)
Reel motor applied voltage selection} Due to the “H’/“L” action of the pins 14 (RPC1) and 15 (RPC2) of microprocessor
switch 1C12, Q47 and Q48 turn ON/OFF to vary the voltage applied to the pin 4 of reel motor
driver JC 1C15 in such a manner that it becomes 8 V for assist, 6 V for fast forwarding
or rewinding or 3.5 V for play or recording.
Reel motor mode | RPC1 RPC2
L
L
H
L
2SC3246
Capstan motor ON/OFF switch For recording or play, the pin 13 (CPM) of microprocessor 1C12 becomes “H” so that
Q49 turns ON to rotate the capstan motor.
2SC3246
2SC1740S (Q, R)
2SC945 (A) (Q, P)
2SC1740S (Q, R)
2SC945 (A) (Q, P)
2SA933S (Q, R)
2SA733 (A) (Q, P)
2SB941 (Q, P)
DTC124ES
REC + PLAY H ON
OTHER L OFF
Due to the “H"/“L” action of the pin 12 (SOL) of microprocessor IC12, Q50 turns
ON/OFF to realize each operation mode of the mechanism.
Solenoid ON/OFF switch
Reel pulse detector For supply reel pulse.
Receiving the output “H"/“L” pulse of the photoreflector, Q51 turn ON/OFF.
Reel pulse detector For takeup reel pulse.
Receiving the output “H"/*L” pulse of the photoreflector, 052 turns ON/OFF.
Due to the ON/OFF operation of the HALF, REC INHIBIT, CHROME or METAL switch
used with the mechanism, Q53~Q56 turns ON/OFF correspondingly. Microprocessor
1C12 thus discriminates the cassette tape.
Q53 for HALF, 054 for REC INHIBIT, Q55 for CHROME, O56 for METAL.
FL display circuit regulated power supply.
Key matrix switches
—30 V power supply
HX siow start switch
For the switch logic to slowly turn up the bias oscillation waveform for recording, refer
to the pertinent description under 024.
M5220P
Playback EQ amplifier
CXA1330S
Playback DOLBY noise reduction
MB84066BM
MPD4066BC
Monitor selection switch Selection between tape monitor and source monitor
CXA1330S
Recording DOLBY noise reduction
M5218P
NJM4558D
‘Recording amplifier
MPC1297CA
HX PRO IC
TD62554S
Normal/chrome tape bias setting
Chrome
INVERTER 1: ON
INVERTER 3: ON
Normal
INVERTER 2: ON
INVERTER 4: ON
Leh
Rech
TD62554S
Bias step Refer to the pertinent description under Q26~Q29.
M5218L
M5218P
NJM4558D
Headphone amplifier
Meter amplifier
Refer to the pertinent description under Q40.
BA6138
Meter drive amplifier 1/2 power compressor amplifier
aa

“ag
Sagi
omponent(s)
1C12
Name
M50941-317SP
CXD1067P
CIRCUIT
Use/function
KX-4520
DESCRIPTION
Operation/condition/compatibility
Microprocessor
Extension IC
M519517ASL
PST529D
Reset IC
Refer to a separate section.
Refer to a separate section.
BA6229
Ree! motor drive IC
AN7908F
MPC7908HF
The
pin
6
of
IC15
is
made
“L"
to
drive
the
reel
motor
in
the
forward
direction,
whereas
the pin
5
of
IC15
is
made
"L”
to
drive
it
in
the reverse
direction.
Also
refer
to
the pertinent
description
under
Q47
and
048.
Signal system regulated power supply
AN7808F
MPC7898HF
MPC7812H
MPC781 2HF
= V power supply
+8 V power supply
Signal system regulated power supply
+12 V power supply
Mechanism and microprocessor system regulated power supply
MPC7805H
MPC7805HF
NJM78L05A
MPC78LO5J
+5 V power supply
Microprocessor system regulated power supply
+5 V power supply
Display unit (X25-3770-00)
ne
Q2
Q3
Name
2SC17408 (Q, R)
2SC945 (A) (Q, P)
2SC1740S (Q, R)
2SC945 (A) (Q, P}
2SC17408 (Q, R)
2SC945 (A) (Q, P)
2SC17408S (Q, R)
2SC945 (A) (Q, P)
MPD7564CS-113
Current buffer for 1GA
Current buffer for 1GB
Current buffer for 2GB
Remote contro! reception
microprocessor
Tape selector driver regulated power supply
Operation/condition/compatibility
Compatible
if
Vebg
is
more
than
50
V
and
lemax.
is
more
than
100
mA.
Compatible if Vepo is more than 50 V and Icmax- More than 100 mA.
Compatible
if
Voy
is
more
than
50
V
and
!omax-
More
than
100
mA.
At
POWER
ON,
the
port
q
of
IC12
(X26-1240-00
A/21)
becomes
“H”
from
“L"
and
the
output
of
Q4
becomes
“L”
from
“H”
to
reset
IC1.

KX-4520
Key name
CIRCUIT DESCRIPTION
Description
PLAY KEY
>
(I<)
Conditions of
nonacceptance
When pressed singly, the play mode is engaged.
@ Play stops at the tape end.
When pressed simultaneously with the REW key, the tape is rewound, then
played.
® Concurrently with the pressure, the tape is rewound.
@ Play starts at the tape head.
@ During CCRS
@ During AUTO BIAS
operation
@ Without cassette half
Display
>
3.45
Linear counter
Ad
Flickers
>»
Lights
Linear counter
STOP KEY
L
When pressed, all operation stops.
@ When pressed during CCRS, the CD player also stops.
When pressed simultaneously with the FF key, the tape zero-stops in the FF
direction.
®
Concurrently
with
the
pressure,
the
tape
is
fast
forwarded
and
when
the
linear
counter
display
reaches
“0.00”,
stops.
When pressed simultaneously with the REW key, the tape zero-stops in the
REW direction.
©
Concurrently
with
the
pressure,
the
tape
is
rewound
and
when
the
linear
counter
display
reaches
"0.00",
stops.
EJECT SW
When pressed, all operation stops and the cassette half is ejected.
@ When pressed during CCRS, the CD player also stops.
els
@ During CCRS
@ During AUTO BIAS
operation
@ Without cassette half
® During play
® During recording
Linear counter
>>
Linear counter
dd
Linear counter
Linear counter
The tape selector display goes
out.
PAUSE KEY
REC KEY
TAPE/SOURCE
KEY
1. When pressed during play, the play pause mode is engaged.
When pressed during recording, the recording pause mode is engaged.
2. When pressed simultaneously with the REC key, the recording pause mode
is engaged.
1.
When
pressed
during
stop
or
recording
pause,
the
recording
mode
is
entered.
2. When pressed simuitaneously with the PAUSE key, the recording pause
mode is enyaged.
3. When pressed during recording, ARM (auto recording mute) is performed.
@ The recording mute mode is engaged. 4 sec after, the recording pause
mode is entered.
1. Selection is made between tape and source.
@ At power ON, the tape is engaged.
@ For play or recording, the tape is automatically engaged.
@ For recording pause, the source is automatically engaged.
————__—__—__
®@ During CCRS
@ During AUTO BIAS
operation
@ Without cassette half
@ During CCRS
@ During AUTO BIAS
operation
@ Without cassette half
@ Without recording tab
@ During CCRS
@ During AUTO BIAS
operation
® Without cassette half
@ Without recording tab
PLAY PAUSE b> ff]
REC PAUSE p> J] @
Linear counter
REC
> ©
>ile
> @
Lights Flickers
REC PAUSE
Linear counter
@ During CCRS
@ During AUTO BIAS
operation
+————
For tape TAPE
SOURCE
For source
COUNTER
RESET KEY
AUTO BIAS KEY
1. The linear counter is reset to “0.00”.
@ While pressed, “0.00” is held.
@ When pressed during zero-stop, the stop mode is engaged.
1, The AUTO BIAS operation is performed.
@ The tape is fast forwarded (FF) for 1 second.
@ After that, up'from the deepest bias step, 400 Hz and 10 kHz are recorded
alternately
(300
msec
each)
and
level-checked
repeatedly
(300
msec
each)
up to the fullest range. In this process, when 400 Hz level < 10 kHz level,
the operation hereat stops and the tape is rewound to the start point.
@
When
pressed
when
the
auto
bias
setting
is
already
made,
the
setting
is
canceled.
(However,
the
setting
cannot
be
canceled
during
recording.)
© For between tape and source, the tape is automatically selected.
adams CCRS
® During AUTO BIAS
operation
@ Except during stop
@ Without cassette half
@ Without recording
inhibit tab
During setting AUTO
BIAS
Flickers
Setting already made
AUTO
BIAS
Lights
CCRS KEY
+
10
The deck enters the CCRS operation together with the CD player.
© For operation, refer to a separate paper.
an
@ During CCRS operation
® During AUTO BIAS
operation
@ Without cassette half
®@ Except during stop
@ Without recording
inhibit tab

O
CIRCUIT DESCRIPTION
Key name Description
Conditions of
Display
nonacceptance
TIMER
PLAY
SW]
1.
With
this
switch
set
to
ON,
the
play
mode
is
automatically
engaged
4
@
Without
cassette
half
seconds later from power ON.
TIMER
REC
SW
.
With
this
switch
set
to
ON,
the
recording
mode
is
automatically
engaged
4
seconds
later
from
power
ON.
@ Without cassette half
@ Without recording
inhibit tab
Bilateral
easy
.
The
bilateral
easy
operation
or
synchronous
recording
ON/OFF
selection
is
operation
made.
ON/OFF switch @ For operation, refer to a separate section.
Test Mode
1.
Setting
of
test
mode
@
Any
key
is
accepted
irrespective
of
the
half
switch
and
Shorting
the
test
pin
(TP3
-+
TP4),
turn
the
power
ON.
the
recording
inhibit
tab.
2.
Contents
of
test
mode
@
The
AUTO
BIAS
setting
is
performed
in
a
shorter
mode
@
At
power
ON,
the
FL
display
is
all
lit.
(1/3
the
normal
speed)
in
16
steps
at
any
case
without
With
a
key
ON
or
for
timer
play
or
timer
recording,
the
LINE
OUT
muting.
FL
display
is
canceled
from
all
lighting.
3.
Cancellation
of
test
mode
@
Each
key
is
accepted
after
1
second
from
power
ON.
The
test
mode
is
cancelled
by
pressing
the
PAUSE
key.
@ The recording mode is accepted from any mode what-
soever.

KX-4520
12
CIRCUIT DESCRIPTION
About Bilateral Easy Operation ON/OFF Switch Function
The operation varies as follows depending upon the ON/OFF setting of the bilateral easy operation ON/OFF switch:
Switch status
Combination
XR (ON)
1. System Component/
Receiver
Connected to terminal TAPE 1.
@ Easy operation is performed.
@ Synchronous mode (PHONO, CD) is performed.
® During recording, the selector of the amplifier and the
TAPE 2 monitor key are locked.
KA-V7000
KA-V6000
KA-V4000
Synchronous mode (PHONO, CD) only is performed.
(However, the input selector and the REC OUT selector should
be the same in setting.)
Component unit and
KA-V5000
© Easy operation is not performed.
@ Synchronous mode is not performed.
XS (OFF)
Connected to terminal TAPE 2.
@ Easy operation is not performed.
@ Synchronous mode is not performed.
@ During recording, the selector of the amplifier and the
TAPE 2 monitor key are not locked.
® Easy operation is not performed.
@ Synchronous mode is not performed.
@ Easy operation is not performed.
@ Synchronous mode is not performed.
“ However, in any case, the synchronous mode is performed in recording after CCRS operation. (CD player only) In additon, an
operation by the system remote control is accepted in any event. (Deck-B code)
EDIT CCRS Operation
1, Press the CCRS key.
@ The recording pause mode is engaged automatically.
(This operation is canceled unless a reply is given within 30 seconds from
the CD player.)
@ When the STOP or EJECT key is pressed, this operation is canceled. Any
other key is not inhibited.
CD player
@ Peak point sampling starts.
@ in the time display, the CCRS portion lights.
@ When the STOP or OPEN/CLOSE key is pressed, this operation is
2. Seeing the level meter, adjust the REC level control.
3. When the recording level is OKed, press the REC key.
@ The recording mode is engaged.
(The synchronous recording mode is engaged. When either side stops, the
synchronous recording mode is canceled.)
@ Any key is accepted.
@ Upon the termination of recording the side A, the stop mode is engaged.
4, Side A — Side B
5. Press the REC key.
cancelled. Any other key is inhibited.
@ Play is automatically made from the beginning of that tune.
@ Any key is accepted.
@ The time display returns to previous.
@ Upon the termination of playing the file of the side A, the pause mode is
Ye.
engaged at the head of the file of the side B.
6. Press the PLAY key. “

KX-4520
O
CIRCUIT
DESCRIPTION
} ‘Circuit Operation This DOLBY IC is operable on either a single power or
DOLBY IC (CXA1330S) positive/negative dual power as shown below:
Comparing the new DOLBY IC used in this unit with the ; j
:
Pint6
|
Pin
15
Pin
17
conventional DOLBY IC...
Single power Connected to GND through
chemical capacitor
1. Simplified 1/0 circuitry by virtue of fixed I/O gain
PB-IN —30 dBs, REC OUT —6.0 dBs
REC IN—~25dBs, MONITOR OUT OdBs Positive/
negative dual +Vec
power
(at DOLBY level, O dBs=0.755 V)
2. Smaller number of externally connected parts owing to
great omission of capacitors within side chains
There only remain high-level and low-level DET rectifi-
cation capacitors and spectrum skewing twin T filter.
3. Compatibility with two modes, passing and non-
Note: Pin 17, which is the input of the internal reference
power, is subject to resistor-division between pins 16 and
15 into 1/2 Vec (GND).
passing of line input through MPx filter wee
The DOLBY NR mode is controlled by voltage selec- if
oan tion, basically as shown in Figure1. c 22K
! 3 The DOLBY input selection is as follows: B open 5 to 1C26 pin (NRSW)
Through MPx filter . .. MPX OFF Op
Not through MPxX filter... REC ?
For
playback
input...
PB
Figure
1.
NR
mode
selection
(on
single
power)
This control is made by voltage selection, basically as +Vec
shown in-Figure 2.
MPX 22K
REC open oy to IC Spin (MODE)
aon
P.B.
?
Ou
Figure 2. Mode selection (on single power)
FB.C LINE OUTE vet REC OUT! vss
LINE INI PB ING veT | OFF B.C ee ab shia
S60(IX)
2.2nk2x)| 2.2 n{2X)
Ri4
en
aa?
2
LINE OUT
Rt
AW 27K UX)
C23 /C24
Z fi
af
-
b
8
Pe
Sie
cae
te
ab
.
GN
GND
KJ
LINEIN2
PB
IN2
vcT2
MODE
LINE
OUT:
2
“cre
D
necout2
SX
exp
a,
MPX
REC
PB
13
Me

~ KX-4520
CIRCUIT
DESCRIPTION
Microprocessor
(M50941-317SP)
Pin
Connections:
VREF —e | 1 |5y Vec
IN-L
AVcc
IN-R a
PH-S
b
PH-T
c
D d
R.
SW.
©
:
B f
A
g
L.
MUTE
h
R.
MUTE
i
+
FL
segment
SOL
j
cpm +— [13] = k
RPC!
=<
[ia]
°
|
RPC2 «— [15] i m
~
FF
+—
[16]
'
n
REW
<—
2
)
CLK
+—
[is]
.
p
CXD1067;DATA
«—
[i9|
vU
q
STB + ]20) IGA
BUSY ++ [21}BuSY 2GA
DATA
«+
{22]SDATA
3GA
OSC
OUT
+—
[23}0SC
OUT
4GA
}
FL
digit/Key
scan
R.
DATA
—»
[24iRDATA
5GA
BIAS
+—
[25]B1AS
IGB
2GB
RESET —>
Xin
—>
28]
RO
ea
aa
29)
i
Key
input
GND
R2
R3
GND
KEY
6
KEY
5
KEY
4
KEY
3.
KEY
2.
KEY
1
TIMER
REC
HALF
Sw
AUTO
ae
BIAS
Rt
TIMER
|
TEST
|
||
BILATERAL
re
<{oo.ny
e
ATER
|
R3
IGB
2GA
1GA 3GA
Key Matrix
14
ie
TAPE/
SOURCE
4GA
SGA

| KX-4520
e CIRCUIT DESCRIPTION
(4 Pin Functions of M50941-317SP:
Pin
Name
Signal
name
Description
VREF
5V
INPUT-L Music signal input (A/D) L-ch
INPUT-R Music signal input (A/D) R-ch
PH-S Linear counter pulse input, auto stop input (supply reel side)
PH-T Linear counter pulse input (takeup ree! side)
D.C.B,A Mechanism rotary switch input pins
LINE-MUTE LINE OUT mute pin, mute at “L"
’
REC-MUTE
Recording
amplifier
mute
pin,
mute
at
“L”
Mechanism solenoid output. Solenoid ON at “H”
Mechanism capstan motor output. Motor ON at “H"
Reel motor voltage selection pin. 3.5 V at “H" and otherwise “L”
Reel motor voltage selection pin. 6 V at “H” and otherwise “L”
{
Reel motor direction selection pin STOP REWIND
1 0 j
Reel motor direction selection pin
Clock output pin for CXD1067
Data output pin for CXD1067
Strobe output pin for CXD1067
BUSY Inter-unit serial communication BUSY pin
SDATA Inter-unit serial communication DATA pin
a)
23
P32
O
OSC OUT
Auto
bias
400
Hz/10
kHz
square
wave
output
pin
Ld
3
24
P31
|
RDATA
Input
pin
of
serial
data
from
remote
control
microprocessor
25
P30
(e]
BIAS
BIAS
signal
control.
BIAS
ON
at
“H”
26 CNVss
27
ae
RESET 1 Reset input pin
p22
fxm
Pt
PT
ci
inst
in
Clock
output
pin
GND
|
OPEN
C
%
Power
supply
pin
(GND)
aS
OPEN
Key scan input pins ("H" with key ON)
Vp Port PO, P1 or P2 pull-down voltage input pin
P17~P11
2GB~1GA
FL
digit
or
key
scan
output
pins
P10, PO, P2 ie) Q-8 FL segment output pins
»
AVcc 5V
Vec Power supply pin (5 V)
15

KX-4520
CIRCUIT DESCRIPTION
BIAS1 5V
BIAS2
BIAS3
BIAS4
OSC/LINE —> Reset
400/10K 5V
DOLBY C/B OPEN
DOLBY ON/OFF Metal
TAPE/SOURCE Chrome
Normal
Pin Functions of CXD-1067P:
Pin name 1/0 Signal name
oO
400/10K
BIAS 1
Description
BIAS Deep
AUTO BIAS bias :
1
level varying input 1
1
AUTO BIAS oscillator filter select pin. 10 kHz at “L”
DOLBY C/B
DOLBY ON/OFF
TAPE/SOURCE
|
DOLBY mode select pin. DOLBY C at “H”
DOLBY ON/OFF pin. DOLBY ON at “H”
Tape/source select pin. Source at "H"
1
Power supply pin (GND)
O;JO;O;O;OJO
NORMAL
Tape select circuit control pin. Normal tape at “L”
CHROME
|
Tape select circuit contro! pin. Chrome tape at “L”
METAL
-Felele'
OPEN
Tape select circuit control pin. Metal tape at “L”
5V
Reset input pin
Data strobe input pin
Data input pin
{
Data clock input pin
16
Power supply pin (5 V)

a KX-4520 KX-4520
oe
CIRCUIT
DESCRIPTION
CIRCUIT
DESCRIPTION
oe
Microprocessor
{
»PD7564CS-113)
(b)
LED
flickering
during
remote
control
code
recep-
:
Timing
chart
1.
Remote
control
reception
tion
(a)
This
receives
the
remote
control
custom
code
The
LED
flickers
at
cycles
of
64
msec
during
STOP
TO
EF
FF
TO
STOP
STOP
TO
REW
REWTOSTOP
,
“B749"
for
a
single
cassette
deck,
converts
that
remote
contro!
code
reception.
;
e
io
F
aa
1008
data
code
to
a
serial
code
(with
the
same
format
as
(c)
Remote
control
key
OFF
detection
9
500
o
500
1900
for
system
control),
which
is
in
turn
output.
Upon
termination
of
remote
control
code
reception;
a
ae
Gee
7a
as
aa
ames
a
a
ms
i
a
a
Sts
t
(However,
the
system
control
is
given
priority.
For
the
code
“27”
is
output
as
the
key
OFF
signal.
Sine
pea
_
m
KEY
IN
a
mM
_
this
reason,
when
the
bus
is
busy,
no
remote
con-
(12
SOL
por
Re
eee
GSe
an
np
aces
ee
PINNo.
NAME
“ie
trol signal is received.)
(12
SOL
V,
—
——as
{13 CPM (13 CPM
|
(16
FF
(16
FF
330
|
BUSY
{17
REW
(17
REW
To
exclusive
5
(14
RPC1
(14
RPC1
me DATA input
* {15 RPC2 (15 RPC2
wv.
10LM
wt
LED
during
light
reception
(1OLM
(10
») +5V
Remote contro! -
light receiver REMOTE P03 = Pitt eee
re
aes
a
z
STOP
TO
REC/PLAY
REC/PLAY
TO
STOP
cee
>
=
f)
Fe)
(e)
500
1000
1500
ie)
500
1000
1800
in.
o
=
+—}—_+—_
+++
+--+
Pr
qe
tds
e
le
cigs) ae
Ici2
46PIN
KEY
IN
im
ines
da
foome
PIN No. NAME
(12 SOL ie n
400kHz
Ceramic
(3CPM)
pe
Dee
oe
ero
oe
nee
yoy 3% u arpa eee wee ae ere
ates ‘ O +5y : Ucar aes ‘ : : Le
4)
IGEN
em
ae
roms
peal
ee
cere
MG RRCH oe ey eg ee
Pin
Functions
(16
RPC2
i
eae
ii
:
Bias
|
Pin
name
Description
.
|
Pin
name
Description
OLM
)
: :
fs
:
:
2
ie
:
\
Poo
Unused
RESET
Reset
input
pin
(*H"
reset)
.
come
.
i:
aie
=
>
2
Pot
Busy
input
pin
P100
O
|
Unused
(N-ch
output)
: :
re
re
ee
er
a
{SOL ) a3 : :
i
3
P02
Unused
P101
fe)
|
Unused
(N-ch
output)
:
a
ee
pacar
Oe
eS.
ae
4
|
Pos
Remote
contro!
signal
input
pin
(Active
°L")
P102
O
|
Unused
{N-ch
output)
(CPM
ie
:
:
:
3 :
: 7 ‘
: ‘
fi
a
‘
:
5
P30
Unused
({N-ch
output)
P103
1e]
Unused
{N-ch
output}
ij
: :
:
:
: :
: ;
11R Se ee
6
P31
Unused
{N-ch
output}
P1110
ie)
DATA
output
pin
{CMOS
output)
{
!
:
Bong
a
breed
—
—~—
=
7
P32
Unused
(N-ch
output)
PIT}
io)
BUSY
output
pin
(CMOS
output)
(25
BIAS
Wan
8,
Se
ets
ees
or
pe
he
ae
:
:
Ss
8 CL2 Clock oscillation pin {400 kHz) P112 ° Unused (N-ch output) (6D ) : : 5 : “ : =
“Fr
rs
9
Cu
Clock
oscillation
pin
P113
ie)
LED
drive
pin
{N-ch
output)
aed
; %
10
VDD
Power
supply
pin
(+5
V)
VSS
a
GND
7c
)
Poe]
rm
jo
ef
eer
(ie
er
(8B
)
: :
ea
Me
a
a
17
18

KX-4520 KX-4520
CIRCUIT
DESCRIPTION
MECHANISM
DESCRIPTION
€
AUTO
BIAS
8.
Brakeass’y
6.
Reelstand
70.
Reel
14.
Idler
6.
Reel
stand
€
PIN
No.
NAME
(12
SOL
)
(13CPM)
(16
FF
)
(17
REW
)
7.
Brakeass’y
(10
LM
)
(11.
RM
)
(23
OSC
)
Main
motor
71.
Solenoid
{25
BIAS
)
(«1
BIAS1
)
12.
Assist
gear
2BIAS2.
)
(«3
BIAS3
}
(=4B1AS4)
(«5
O/L
)
"ys
©
("6
FIL
)
13.
Cam
gear
2.
Head
base
{»8
DOLBY
)
(=
9
T/S
)
STOP
—
FF
or
REW
(Press
the
FF
or
REW
key.)
(1)
The
reel
motor
(70)
starts
to
rotate
in
the
direction
of
arrow
@.
SME
CAM
FLOW
(2)
At
the
same
time,
the
solenoid
(71)
works
to
operate
Pa
aes
the
brake
assy
(7,
8)
in
the
direction
of
arrow
@.
€
:
Direction
RVS
FWD
(3)
As
the
idler
gear
(14)
becomes
free
for
a
small
time,
i
i
PAE]
an
SI
{STOP
TPAUSE
the
takeup
reel
(FF)
and
the
supply
reel
(REW)
are
put
MODE
Puy]
Oe
Fe
pa
ae
PLAY
into
engagement.
CAMANGLE
|
20°}
24°
/18"}
46"
fasta]
aes
463°
|W"
45)
46°
|
18°|
24°
|20°
(4)
Either
ree!
stand
(6)
starts
to
rotate
to
provide
the
FF
-
+
—+—
—+—}—4
or
REW
operation
@
H
eee
(ea
a
|
L
ef
ce
ROTARY
H
sw
L
|
H
|
HEAD es
page PAUSE
POsI-
@
}
TION
stop
_t
20

A
\
“apc
MECHANISM DESCRIPTION
“STOP — PLAY/REC
(Press the PLAY/REC button)
(1)
(2)
(3)
The reel motor {70) starts to rotate in the direction of
arrow 1] ;
Due to the brake assy (7, 8), the idler gear (14) con-
tinues to rotate at the central position.
The rotation of the reel motor (70) is transmitted to
the cam gear (13) through the idler gear (14) and
assist gear (12).
By the cam of the cam gear (13), the boss (A) on the
head base is pushed up.
At this time, as the solenoid (71) works for a small
time... @ . the brake assy (7, 8) moves in the direc-
tion of arrow 6} and the idler gear (14) thus engages
with the takeup reel (6)... 7) , o that the tape is
wound to enter the PLAY/REC operation... @
PLAY/REC — STOP
(Press the STOP key)
(1)
(2)
(4)
The reel motor (70) starts to rotate in the Girection of
arrow @ , and the idler gear (14) is thereby rotated
and moved in the direction of arrow 2] to the central
position.
The cam gear (13) starts to rotate to lower the head
base (2).
At this time, as the solenoid (71) works... @ . the
idler gear (14) is disengaged from the brake assy (7, 8)
and is moved in the direction of arrow 5] so that the
supply reel (6) is slightly rotated 6} to rewind the
tape.
Again the reel motor (70) rotates reversely 7) to
return the idler gear (14) tothe central position, after
which tt stops.
%
KX-4520
21

KX-4520
ADJUSTMENT
INPUT | OUTPUT CASSETTE TAPE ALIGNMENT
oie SETTINGS __ SETTINGS DECK SETTINGS POINTS eis ua
Unless otherwise specified; each switch should be set as follows: 0 dBs ~ 0.775 V
TAPE: NORMAL, DOLBY,: OFF, INPUT: LINE
|. Cassette mechanism section (REC/PB head adjustment)
Demagnetize the REC/PB head by
REC/PB head, | \ead eraser. Clean the REC/PB
re eta Es = piste at demagnetization, pha bea head. rasa head’ capstaniand
9 cleaning Bey SiG pinch roller with a cotton swab
pl immersed in alcohol.
In a setting where the output is
maximized, adjust the azimuth
ea are adjustment screw so that the
: im aoe , .
‘ ; Lissajous figure appearing on the
[2] REC/PB head TCC-183 (B) PLAY adjustment oscilloscope screen comes near to} (a)
azimuth 10 kHz rew :
mera sc a line slanted 45°.
Note: The head should be ;
installed in such a manner that It
approaches the tape face.
pel Aen Semi-fixed
SCC-1727 eae Adjust so that frequency is 3 kH2 | |,
{31 | Tape speed TCC-100 (B) PLAY replete! in an tthe canterof the-tape. (b)
3 kHz, —4 dB motor assembly
Il. PC board adjustment
MTT-150, Adjust so that LINE OUT is
TCC-130 400 Hz —1.0 dBs.
MTT-256, : :
<1>| Playback level | SCC-1727 (B) PLAY MEE NBSIRI (CARIBE 60 MEU EINE Ohlie
(X26-124) —4.0 dBs.
315 Hz
MTT-256U, ; :
TCC-160 315 Hz Adjust so that LINE OUT is 0 dBs.
(A) 1kHz Adjust the REC VR (LEVEL, Record 1 kHz and 10 kHz ;
30 dBs BALANCE) so that the REC VR7(L) VR&(R) alternately, and adjust each bias
<2> | Bias current 10 kHz (B) monitor output is —24 dBs at (X26-124) current adjustment VR so that the
—30 dBs 1 kHz, and record and playback 10 kHz play back level is +0.5 dBs
1 kHz and 10 kHz alternately. against 1 kHz.
With the situation in above item ;
‘ (A) 1 kHz, : Sid VR5(L) VR6E(R) | Adjust so that the playback output
Recording level ~30 dBs (B) <2> being kept as it is, record (X26-124) level is 24 dBs.
and play back 1 kHz.
Adjust the REC VR (LEVEL,
(A) 1 kHz,
—10 dBs
FL meter 0 dB
BALANCE) so that the REC VR9(L) VRIO(R) |, aie
— | PAUSE monitor output is —4 dBs | (X26-124) OIE ES Mat OMB. Nlepite,
i at 1 kHz.
Note: On item <1> in “Il. PC board adjustment”
Although 3 kinds of tapes are set forth for the playback level adjustment, the use of one tape suffices for adjustment. Here is meant no necessity
for the use of all these 3 kinds of tapes. Other than the above mentioned tapes, when a test tape equal in magnetic flux and frequency 's
available, the adjustment is feasible with this test tape by making the playback output suited to the specified output level of this tape in
agreement with the adjustment method.
SYSTEM CONNECTIONS —
AC voitmeter ; AC voitmeter
G
Génerateur audio
Voltmétre CA Voltmetre CA
Wechselspan- fréquences Oscilloscope Wechselspan-
nungsmesser
NF-Signal
Oscilloscope
nungsmesser
generator
Oszilloskop
Frequency counter
Fréquencemeatre
Frequenzzahler
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