Harman Kardon DC5300 User manual

The Harman Kardon
Model DC5300
DUAL CASSETTE DECK
Manual 177A
echnical Manual
The following marks found in the parts list of this manual
identify the models as follows.
> : North America area model Black version
@ : international model Black version
: Australia model Black version
CONTENTS
SPECIFICATIONS Qu... ce eeescsccsssceccccssscsecceccccsescees GENERAL UNIT uuu. ce ce eeecsecccecnssescccecscecacsseces 8
LEAKAGE TEST .uc.cccccccccccccccscccessseccceesecescseteceeceuees GENERAL UNIT PARTS LIST wn... ccc ccceecccceeesees 9
CONTROLS AND FUNCTIONS ...2.........ccseeeseeeeees CASSETTE TAPE PLAYER/RECORDER
DISASSEMBLY PROCEDURES .........ceccccsseeccceees MECHANISM, PARTS LIST .....cceecccccccececcecececcees 9
POWER CORD REPLACEMENT ........ccccccceerecorcees WIRING DIAGRAM ............cceccsccsseccccassceeccneesacces 10
BLOCK DIAGRAM u....ecccccssccssccscccscccssccsecacescessceaes P2 CZ BOARDS 2525085 cesceaceceetssed aoc iacé odecaghoteanaviaes 11
CIRCUIT DESCRIPTION uu... cc. c.cccccecccscssccsessscceese ELECTRICAL PARTS LIST ...2........00seessccossseceueeee 13
TIMING CHART. .0.......cccccccsscccssscccesssccssecucscecerenscces IC BLOCK DIAGRAM .........cccccseeccnescccescccseseccseres 20
ALIGNMENT PROCEDURES ...........eccccccececeueeceeee SCHEMATIC DIAGRAM Seeddsatesvesisiniveaecdesteew ee 23
harman/kardon
Parts and Service Office ;
240 Crossways Park West,Woodbury,N.Y. 11797
1112-0010A152 P-129109 2000 Printed in Japan
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SPECIFICATIONS
Nominal Limit
4-track 2 Channel Stereo
Cassette Deck
Track Configuration
+ MECHANICAL SECTION
Record/Playback Tape Speed
Drift 4.75 cm/sec. 0.2% < 2.0%
Heads (Primary/Secondary) 2/1
Wow and Flutter NAB 0.05% < 0.1%
CCIR 0.08%
Take Up Torque 50 gr.cm 35-70 gr.cm
Back Tension 2 gr.cm 2-6 gr.cm
F.FWD Torque 100 gr.cm 70 — 150 gr.cm
_ Rew Torque 100 gr.cm 70 -— 150 gr.cm
F.FWD/Rew Time 85 sec. < 100 sec.
(C-60 Tape)
« AMPLIFIER SECTION
Record/Playback Frequency
Response (at -3 dB) LN 20-18 kHz 20-17 kHz
CrO2 20-18kHz 20-17 kHz
Metal 20-18kHz 20-17 kHz
Copy Mode Frequency
Response LN 40 - 16 kHz 40 - 15 kHz
CrO2 40-16kHz 40-15 kHz
Metal 40 - 16 kHz 40 - 15 kHz
105 kHz +5 kHz
620 mV £1.5 dB
Bias Frequency
Playback Output
Signal-to-Noise Ratio
(at Line Input)
(Input 1 kHz, 100 mV)
IHF-A WTD (at Dolby level)
Dolby NR off LN 51 dB
CrO2.- 54 dB
Metal 54dB
Dobly B NR LN 61 dB
CrO2 64 dB > 60 dB
Metal 64 dB > 60 dB
Nominal Limit
Dolby C NR LN ~ =66dB
CrO2 70dB > 66 dB
Metal 70 dB 2 66 dB
Channel Separation 45 dB 235 dB
Crosstalk 70 dB 2 60 dB
Record/Playback Distortion
(Input 1 kHz)
LN 0.9% $ 2.0%
CrO2. 1.3% s 3.0%
Metal 1.1% s 2.0%
MPxX Filter Attenuation
at15kHz 0.3dB <1dB
at19 kHz 35dB 2 30dB
Erase Ratio (Input 80 Hz)
LN 70 dB 2 60 dB
Metal 61 dB 256 dB
Input Sensitivity
(Input 1 kHz) at Line Input 43 mV 30-80 mV
Input Impedance
(Input 1 kHz) at Line Input 23 kQ 15 - 25 kQ
» DIMENSIONS (WxHxD) 17-3/8" x 5” x 12-5/8"
(443 x 134 x 342) mm
¢ WEIGHT 17.2 Ibs (7.8 kg)
¢ POWER SUPPLY
U.S.A. and Canada models
Internationa! model
AC120V, 60 Hz
AC230V/240V, 50/60 Hz
¢ POWER CONSUMPTION
U.S.A. and Canada models 29 W
International model 31W
These specifications are service target specs.
Specifications and components are subject to change without notice.
Overall performance will be maintained or improved.
LEAKAGE TEST (FOR SERVICE ENGINEERS IN THE U.S.A)
Before returning the unit to the user, perform the
following safety checks:
1. Inspect all lead dress to make
certain that leads are not pinch-
ed or that hardware is not lodged
between the chassis and other
metal parts in the unit.
2. Replace all protective devices
such as nonmetallic control
knobs, insulating fishpapers,
cabinet backs, or shields, isola-
tion resistorcapacitor networks,
mechanical insulators, etc.
3. Be sure that no shock hazard exists; check for
leakage current using Simpson Model 229 Leakage
Tester, standard equipment item No. 21641, RCA
Model WT540A or use alternate method as follows:
Plug the AC line cord directly into a 120-volt AC
receptacle (do not use an Isolation Transformer for
this test). Using two clip leads, connect a 1500 ohm,
10-watt resistor paralleled by a 0.15mF capacitor, in
series with all exposed metal cabinet parts and a
known earth ground, such as a water pipe or conduit.
Use a VTVM or VOM with 1000 ohms per volt, or
higher sensitivity to measure the AC voltage drop
across the resistor.(See Diagram.) Move the reisistor
connection to each exposed metal part having a return
path to the chassis (antenna, metal, cabinet, screw
heads, knobs and control shafts, escutcheon, etc.) and
measure the AC voltage drop across the resistor. (This
test should be performed with the power switch in
both the On and Off positions.)
TO EACH EXPOSED
METAL SURFACE OF
UNIT UNDER TEST
SIMPSON MODEL 229 ETC. FOR
LEAKAGE TEST
TO AC GROUND SUCH
AS WATER PIPE,BX CABLE,
CONDUIT, ETC.
HIGH GROUND
VOLTAGE LEAD
OR +LEAD
VTVM
© AC SCALEO
TEST PROBE
CONNECT TO KNOWN
EARTH GROUND
TO EXPOSED
METAL PARTS
A
reading
of
0.35
volt
RMS
or
more
is
excessive
and
indicates
a
potential
shock
hazard
which
must
be
corrected
before returning the unit to the owner.

CONTROLS
AND
FUNCTIONS
Direction
Mode
Selects one way, reverse, Input Balance
or continuous transport Adjusts recording balance of
mode. left and right channels
Fine Trim
Input Level Adjust when recording.
Adjusts recording level.
Power Switch PRI/SEC Transport Selector
Press to turn unit on/off. Selects which transport (either
Primary or Secondary) is to be
operated by the transport
controls.
arman/kardon DC5300 onda! Cassette Deck
Power
PRI %
<d< PP R
Stop
ug
RECORD MPx ! {4 [op conte wi spo
Stops
tape
movement.
no
Bc
j
1
CE
cory
oo
ac
MEMORY di ake EDIT =MEMORY
Reverse Play .
Begins playback or recording in : ! a : J,
reverse direction. I } ‘ i vel inpuMatance ias Mie Tom ry Ti
Rewind
Rapidly ane = SSC tape.
Eject f 0 é 7 sync
Press to load/remove tape : REVERSE
cassette in Primary transport.
Rec/Pause
Puts cassette deck in Record-
ready
or
Pause
mode.
Dolby
NR
#
Memory
Eject
Selects
Dolb
Press
on:
when
<@<q@
is
pressed,
J
——$———
y
on/off,
Dolby
fape
rewind
to
approximatel
Press
to
load/remove
tape
Play
B
mode,
or
Dolby
C
mode.
Hest
on
aunt
sa
pneey,
cassette
in
Secondary
transport.
Begins
playback
or
Fast
Forward
MPX
Filter
ener
Reset
recording.
Rapidly
advances
tape.
Rec
Mute
Press
when
using
Dolby
noise
Resets
Counter
to
Inserts
blank
space
when
reduction
while
recording
FM
00:00.
recording. stereo broadcasts.
PRI
Iluminates when Primary tape
transport is currently operated by the
transport controls.
SEC
llluminates when Secondary tape transport is
currently operated by the transport controls.
LEVEL
MPX Shows signal level.
Indicates MPX Filter is
engaged.
<<>> 18
Displays operating mode of transport:
Record, Forward Play, Reverse Play,
Fast Forward, Rewind, Pause, Stop.
<<>pP ile
Displays operating mode of
transport: Record, Forward Play,
Reverse Play, Fast Forward,
B -35 -20 -10 -7 -5 -3 -1 OO +1 43 +5 48 Rewind, Pause, Stop.
RECORD a
Illuminates when transport is i
Record mode.
RECORD MPX | | | | | | CONT HISPD
DO
Bc
Oo
BC
4
DO
Bc
illuminates if Dolby B or MEMORY \
rent
Iuminates
if
Dolby
B
or
C
circuits
are
on.
C circuits are on.
TRANSPORT MODE
Indicates transport
mode: one way, auto
reverse, continuous.
MEMORY
Indicates Memory is
engaged.
MEMORY
Indicates Memory is
engaged.
Indicates unit is in Copy
mode.
EDIT
0:00 Indicates unit is in
Indicates tape position Edit mode.
in minutes and seconds. HI SPD
Indicates unit is in High
Speed Copy mode.
Copy
Press to begin automatic
copying procedure.
Hi-Speed Copy
Press to begin automatic high
speed copying procedure.
Sync Reverse
Activates automatic synchronized
reverse copying in Copy and Hi-
Speed Copy modes.
Edit
Press to begin Edit mode.
* NOTE
Dolby
noise
reduction
manufactured
under
license
from
Dolby
Laboratories
Licensing
Corporation.
“DOLBY”
and
the
double-D
symbol
[X]
are
trademarks
of
Dolby
Laboratories
Licensing
Corporation.

CONTROLS AND FUNCTIONS Direction Mode
Selects one way, reverse,
or continuous transport
mode.
Input Level
Adjusts recording level.
Power
Switch
PRI/SEC
Transport
Selector
Press
to
turn
unit
on/off.
Selects
which
transport
(either
Primary
or
Secondary)
is
to be
operated
by
the
transport
controls.
arman/kardon
DC5300
odal
Cassette
Deck
PRI “
a<a >> R
Stop acon MPX
BC
Reverse Play ———_—_—______—
a
Stops
tape
movement.
oo
we
MEMORY
Begins playback or recording in
: . Primary Transpov
reverse direction.
!
(
pau
Rewind
————_$_—$—_———__—_—
*;
me
a
Rapidly
rewinds
tape.
Dffrorey
ec
nr;
Dif.
AUTO-RE|
Eject
Press to load/remove tape
cassette in Primary transport. | REC PAUSE MUTE
Rec/Pause
Puts cassette deck in Record-
ready or Pause mode.
:
a
Dolby
NR
+
Selects Dolby on/off, Dol
(
Play
B
mode,
or
Dolby
C
mod
.
Begins
playback
or
Fast
Forward
MPX
Filter
————
‘
recording.
Rapidly
advances
tape.
Rec
Mute
Press
when
using
Dolby
Inserts
blank
space
when reduction
while
recording
recording.
stereo
broadcasts.
PRI
Illuminates when
Primary
tape
transport
is
currently
operated
by
the
(
.
transport
controls.
!
LEVEL
MPX
Shows
signal
level.
Indicates
MPX
Filter
is
engaged.
<<>> 18
Displays operating mode of transport:
Record, Forward Play, Reverse Play,
Fast Forward, Rewind, Pause, Stop.
B -35 -20 -10 -7 -5 -3 -1 QQ +1 +3 +5 +8
RECORD
Te
INuminates when transport is i
Record
mode.
R
SS
SS
Se
Se
<<
iT
RECORD MPX [7] CONT HISPD
Oo pc Od BC
Illuminates if Dolby B or MEMORY
C circuits are on.
TRANSPORT MODE
Indicates transport
mode: one way, auto
reverse, continuous.
‘ MEMORY
Indicates Memory is
engaged.
Indicates |
mode.
EDIT
10:00
Indicates
uni
Indicates
tape
position
Edit
mode.
in
minutes
and
seconds.
HISPD
Indicates unit is
Speed Copy mc

Input Balance
Adjusts recording balance of
left and right channels
Fine Trim
Adjust when recording.
InputPalance jas A Pcandary Transpprt
C R i
Hi Cut
DIRECTION MODE RESET EJECT ae
| /
Memory Eject
off, Dolby ee Pont akneatt Press to load/remove tape
C mode. pe 0 app y cassette in Secondary transport.
00:00 on Counter.
Reset
} Dolby noise Resets Counter to
cording FM 00:00.
3.
SEC
llluminates when Secondary tape transport is
currently operated by the transport controls.
<<4>pPile
Displays operating mode of
transport: Record, Forward Play,
Reverse Play, Fast Forward,
Rewind, Pause, Stop.
DO Bc
MEMORY Iuminates if Dolby B or
C circuits are on.
PY
é ay MEMORY
jicates unit is in Copy Indicates Memory is
de.
engaged.
tes unit is in
1ode.
sunit is in High
opy mode.
Copy
Press to begin automatic
copying procedure.
Hi-Speed Copy
Press to begin automatic high
speed copying procedure.
Sync Reverse
Activates automatic synchronized
reverse copying in Copy and Hi-
Speed Copy modes.
Edit
Press to begin Edit mode.
* NOTE
Dolby
noise
reduction
manufactured
under
license
from
Dolby
Laboratories
Licensing
Corporation.
“DOLBY”
and
the
double-D
symbol
[X]
are
trademarks
of
Dolby
Laboratories
Licensing
Corporation.

DC5300
DISASSEMBLY
PROCEDURES
(REFER
TO
PAGE
9,
10
and
11)
[1] TOP COVER (133) REMOVAL
Remove 4 screws (A) and 2 screws (B), andthen remove
the Top Cover(133).
FRONT PANEL ASSEMBLY (AA) REMOVAL
1. Remove the Top Cover (133).
2. Disconnect 1 connector (JL901) from (CN904) on the
Main P. C. Board (PCB-1).
3. Remove 6 screws (C) and 3 screws (D), and the
remove the Front Panel Assembly (AA).
4. If necessary, unsolder the lead wires.
CASSETTE TAPE RECORDER MECHANISM
ASSEMBLY (103) REMOVEL
1. Remove the Front Panel Assembly (AA). (Refer to
Step 2.)
2. Disconnect 4 connectors (LCN101/351, LCN801,
LCN802 and LCN803) on the Primary Transport P. C.
Board (103).
3. Remove 4-screws (E), and then the Cassette Tape
Recorder Mechanism Assembly (103).
[4] CASSETTE TAPE PLAYER MECHANISM
ASSEMBLY (104) REMOVAL
1. Remove the Front Panel Assembly (AA). (Refer to
Step 2).
2. Disconnect 4 connectors (LCN151, LCN806, LCN807
and LCN808) on the Secondary Transport P. C.
Board (104).
3. Remove 4 screws (F), and then the Cassette Tape
Player Mechanism Assembly (104).
[5] MAIN P. C. BOARD (PCB-1) REMOVAL
1. Remove the Front Panel Assembly (AA). (Refer to
step 2).
2.
Disconnect 4 connectors (LCN151, LCN806, LCN807
and LCN808) onthe Secondary TransportP. C. Board
(103).
. Disconnect 4 connectors (LCN101/351, LCN801,
LCN802 and LCN803) on the Primary Transport P. C.
Board (104).
. Disconnect 5 Jumper Leads (JL1, JL2, JL3, JL4 and
JL5) from 5 connectors (CN805, CN804, CN803, CN802
and CN801) on the Power P. C. Board (PCB-4).
. Remove 9 screws (G), 1 screw (H) and 2 screws (I)
and then remove the Main P. C. Board (PCB-1).
POWER P. C. BOARD (PCB-4) REMOVAL
1.
2.
3.
4.
Remove the Front Panel Assembly (AA). (Refer to
step 2).
Disconnect 5 Jumper Leads (JL1, JL2, JL3, JL4 and
JL5) on the. Power P. C. Board (PCB-4).
Disconnect 3 connectors (LCN801, LCN802 and
LCN803) on the Primary Transport P. C. Board.
Remove 5 screws (J) and 4 screws (K), and then
remove the Power P. C. Board (PCB-4).
OTHER P.C. BOARDS REMOVAL
1.
2.
3.
Remove the Front Panel Assembly (AA). (Refer to
step 2).
Remove 4 screws (L), and then remove the Cont
SW-L P. C. Board (PCB-7).
Remove 3 screws (M), and then remove the Cont
SW-R P. C. Board (PCB-6).
. Remove 3 Rotary Knobs (146) and 3 screws (N), and
then remove the Volume P. C. Board (PCB-2).
. Remove 7 screws (QO), and then remove the Front P.
C. Board (PCB-5).
POWER CORD REPLACEMENT (FOR SERVICE ENGINEERS OTHER THAN NORTH
AMERICA)
In order to prevent fire shock hazard when replacing the power cord, follow the Procedure below to replace the part
with the standard supply parts.
Pi
POWER CORD
PCB-4
CABINET BACK
100mm
MAX.
8mm
The signal from the playback head (Primary Transport)
is amplified by the playback amplifier Q101, Q103 and
Q.105 (L ch.), and is applied to the pin 29 (L ch.) and 2 (R
ch.) of the Dolby NR 1IC501 (B/C type) through the
Switching 1IC701. Use the same signal for both the
secondary transport and the primary transport.
Switching of the playback signal from the record mode
(external input signal) to the playback mode is per-
formed inside IC501.
IC501 is usually switched to the playback mode. How-
ever, the control signal transmitted to the pin 5 of IC501
from 1C751 through 0505 and 0506 switches IC501
from the record mode to the playback mode. The input
signal to IC501 is output from the pins 25 (Lch.) and 6 (R
ch.) and applied to the OUTPUT AMP.
RECORD SIGNAL
The
signal
from
the
INPUT
jack
is
controlled
by
the
INPUT
LEVEL
control.
It
is
applied
to the
pins
30
(L
ch.)
and 1(R ch.) of the Dolby NR 1C501 (B/Ctype): Switching.
of the record signal from the playback mode to the
record mode is performed inside IC501. The control
signal transmitted. to the pin'5 of 1C501 from [C751
through Q505 and Q506 switches 1C501 from the play-
back mode to the record mode.
The input signal to the Dolby NR IC is Siku from the
pins 28 (L ch.) and 3 (Rch.) of C501 and passed through
the MPX filter. Then it is input to the pins 27 (Lch.) and
4 (R ch.) and is output from the pins 24 (L ch.) and 7 (R
ch.). The encoded signal is input to the pins 23 (L ch.)
and 8 (Rch.) and then it is output from the pins 18 (Lch.)
and 13 (R ch.). The signal output from 1C501 passes
through the record equalizer circuit and is amplified by
the record amplifier of 1C201. The amplified signal is
then applied to the recording head after being
synthesized by a bias signal. ©
INPUT LEVEL
25 Jt
MPX DOLBY —9
Ji
OUTPUT
HL
B.C
NA
CIRCUIT
INPUT Apel
J2
PLAYBACK AMP Sut
Q101—-106
REMOTE
8{
SWITCHING
J3
RPH1
PRIMARY
~~
(7a
IN
=
I
| ie
I [
EQUALIZER | +—{ ><] SOLENOIA
CIRCUIT
!
of
1
(AEE
| Q201— 212 ICaot}-agnteet
Peiciee
S|
b--}----4----4------}-----=-
LOGIC
CONTROL
[aga
GAP
STAN
ae
Arsh
SOLENOIA
SECONDARY
~~
—_—
Hn REEL |SECONDARY
CAPSTAN
MOTOR
EMI ita es
MAIN CONTROLLER
FeApe 7 ic901
$913
S910
S909
S911
S914
S904
S908
S902
__—-sg05
$016_$920_s918
$912 $915 $907 $906
PLAYBACK SIGNAL MUTING OPERATION
The signal that mutes the sound produced at switching
to recording or playback is applied from IC751 of the
logic control block.
When the “STOP” button is pressed, the mute signal
output from the pin 22 of IC751 turns ON Q709 (L ch.)
and Q710 (R ch.) to short-circuit the output signals of
the playback amplifiers for muting. For the purpose of
preventing generation of noise at power ON/OFF, the
mute signal is output from 051. The muting is done by
short circuiting the output signal with Q709 (L ch.) and
Q710 (R ch.) turned ON.
LOGIC FOR RECORD MODE
When the “REC” button is pressed, the pin 11 of IC751
becomes high level and 0109 (L ch.) and Q110 (R ch.)
turn ON. The input to the Dolby NR IC is muted. Also
Q712 and Q713 turn ON and Q711 turns OFF. Therefore
0701, 0703 (L ch.) and Q702, 0704 (R ch.) turn OFF to
release the muting of the outputs from the record
amplifiers.
Also, 0505 turns ON and 0506 turns OFF to make the
pin 5 of IC501 high level. Therefore the mode is
switched to the record mode.
LOGIC FOR RECORD TO PLAYBACK MODE
When the “STOP”, “PAUSE” or “PLAY” button is
pressed, the pin 12 of C751 becomes high level. 0.219
turns
ON
and
Q213
(Lch.),
Q214
(Rch.)
turn
ON
to
mute
the inputs to the record amplifiers. Also, Q712 and
Q713 turn OFF and Q711 turns ON to turn ON Q701,
Q703 (L ch.) and Q702, 0704 (R ch.). Therefore the
outputs from the record amplifiers are muted.
Also, 0505 turns OFF and Q506 turns ON to make the
pin 5 of C501 low level. Therefore the mode is switched
to the playback mode.

DISASSEMBLY PROCEDURES (REFER TO PAGE 9, 10 and 11)
[1] TOP COVER (133) REMOVAL
Remove 4screws (A) and 2 screws (B), andthen remove
the Top Cover(133).
FRONT PANEL ASSEMBLY (AA) REMOVAL
1. Remove the Top Cover (133).
2. Disconnect 1 connector (JL901) from (CN904) on the
Main P. C. Board (PCB-1).
3. Remove 6 screws (C) and 3 screws (D), and the
remove the Front Panel Assembly (AA).
4. If necessary, unsolder the lead wires.
CASSETTE TAPE RECORDER MECHANISM
ASSEMBLY (103) REMOVEL
1. Remove the Front Panel Assembly (AA). (Refer to
Step 2.)
2. Disconnect 4 connectors (LCN101/351, LCN801,
LCN802 and LCN803) on the Primary Transport P. C.
Board (103).
3. Remove 4-screws (E), and then the Cassette Tape
Recorder Mechanism Assembly (103).
[4| CASSETTE TAPE PLAYER MECHANISM
ASSEMBLY (104) REMOVAL
1. Remove the Front Panel Assembly (AA). (Refer to
Step 2).
2. Disconnect 4 connectors (LCN151, LCN806, LCN807
and
LCN808)
on the
Secondary
Transport
P.
C.
Board (104).
3. Remove 4 screws (F), and then the Cassette Tape
Player Mechanism Assembly (104).
[5] MAIN P. C. BOARD (PCB-1) REMOVAL
1. Remove the Front Panel Assembly (AA). (Refer to
step 2).
2. Disconnect 4 connectors (LCN151, LCN806, LCN807
and LCN808) onthe Secondary TransportP. C. Board
(103).
3. Disconnect 4 connectors (LCN101/351, LCN801,
LCN802 and LCN803) on the Primary Transport P. C.
Board (104).
4. Disconnect 5 Jumper Leads (JL1, JL2, JL3, JL4 and
JL5) from 5connectors (CN805, CN804, CN803, CN802
and CN801) on the Power P. C. Board (PCB-4).
5. Remove 9 screws (G), 1 screw (H) and 2 screws (I)
and then remove the Main P. C. Board (PCB-1).
POWER P. C. BOARD (PCB-4) REMOVAL
1. Remove the Front Panel Assembly (AA). (Refer to
step 2). :
2. Disconnect 5 Jumper Leads (JL1, JL2, JL3, JL4 and
JL5) on the. Power P. C. Board (PCB-4).
3. Disconnect 3 connectors (LCN801, LCN802 and
LCN803) on the Primary Transport P. C. Board.
4. Remove 5 screws (J) and 4 screws (K), and then
remove the Power P. C. Board (PCB-4).
OTHER P.C. BOARDS REMOVAL
1. Remove the Front Panel Assembly (AA). (Refer to
step 2).
2. Remove 4 screws (L), and then remove the Cont
SW-L P. C. Board (PCB-7).
3. Remove 3 screws (M), and then remove the Cont
SW-R P. C. Board (PCB-6).
4. Remove 3 Rotary Knobs (146) and 3 screws (N), and
then remove the Volume P. C. Board (PCB-2).
5. Remove 7 screws (O), and then remove the Front P.
C. Board (PCB-5).
POWER
CORD
REPLACEMENT
(FOR
SERVICE
ENGINEERS
OTHER
THAN
NORTH
AMERICA)
In
order
to
prevent
fire
shock
hazard
when
replacing
the
power
cord,
follow
the
Procedure
below
to
replace
the
part
with the standard supply parts.
Pi
POWER CORD
Ba]
rt HOLDER
11
POWER
TRANSFORMER
BLUE
PCB-4
CABINET BACK
100mm
MAX.
8mm

BLOCK DIAGRAM
INPUT LEVEL
VR203, 204
a
input ©
PLAYBACK AMP
Q101-106
8} SWITCHING
RPHI oy
PRIMARY J
EQUALIZER
CIRCUIT
Q201~ 212
PLAYBACKAMP}] {i i
Q151-156
PH1
SECONDARY ~~.
EH1
ERASE X 9
HEAD
CIRCUIT DESCRIPTION
PLAYBACK SIGNAL
The signal from the playback head (Primary Transport)
is amplified by the playback amplifier Q101, Q103 and
Q105 (Lch.), and is applied to the pin 29 (Lch.) and 2 (R
ch.) of the Dolby NR IC501 (B/C type) through the
Switching IC701. Use the same signal for both the
secondary transport and the primary transport.
Switching of the playback signal from the record mode
(external input signal) to the playback mode is per-
formed inside IC501.
1C501 is usually switched to the playback mode. How-
ever, the control signal transmitted to the pin 5 of IC501
‘from 1C751 through Q505 and Q506 switches IC501
from the record mode to the playback mode. The input
signal to 1C501 is output from the pins 25 (Lch.) and 6 (R
ch.) and applied to the OUTPUT AMP.
RECORD SIGNAL
The signal from the INPUT jack is controlled by the
INPUT LEVEL control. It is applied to the pins 30 (L-ch.)
and 1(R ch.) ofthe Dolby NR IC501 (B/Ctype): Switching
of the record signal from the playback mode to the
record mode is performed inside IC501. The control
signal transmitted to the pin'5 of IC501 from 1C751
through 0505 and 0506 switches IC501 from the play-
back mode to the record mode.
The input signal to the Dolby NR IC is output from the
pins 28 (Lch.) and 3 (Rch.) of C501 and passed through
the MP X filter. Then it is input to the pins 27 (Lch.) and
4(R ch.) and is output from the pins 24 (L ch.) and 7 (R
ch.). The encoded signal is input to the pins 23 (L ch.)
and 8 (Rch.) and then it is output from the pins 18 (Lch.}
and 13 (R ch.). The signal output from 1C501 passes
through the record equalizer circuit and is amplified by
the record amplifier of 1C201. The amplified signal is
then applied to the recording head after being
synthesized by a bias signal.
MPX DOLBY
B.C NR CIRCUIT
C501
Q505, 506
$913 S910 S909 S911 S914 S904 S908
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J2
OUT
REMOTE
3
IN
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———=—5
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CAPSTAN
LOGIC CONTROL 10 MOTOR
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MAIN CONTROLLER
IC901
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MUTING OPERATION
The signal that mutes the sound produced at switching
to recording or playback is applied from IC751 of the
logic contro! block.
When the “STOP” button is pressed, the mute signal
output from the pin 22 of 1C751 turns ON Q709 (L ch.)
and Q710 (R ch.) to short-circuit the output signals of
the playback amplifiers for muting. For the purpose of
preventing generation of noise at power ON/OFF, the
mute signal is output from Q51. The muting is done by
short circuiting the output signal with Q709 (L ch.) and
Q710 (R ch.) turned ON.
LOGIC FOR RECORD MODE
When the “REC” button is pressed, the pin 11 of iC751
becomes high level and 0109 (L ch.) and Q110 (R ch.)
turn ON. The input to the Dolby NR IC is muted. Also
Q712 and Q713 turn ON and Q711 turns OFF. Therefore
Q701, Q703 (L ch.) and Q702, Q704 (R ch.) turn OFF to
release the muting of the outputs from the record
amplifiers.
Also, 0505 turns ON and Q506 turns OFF to make the
pin 5 of IC501 high level. Therefore the mode is
switched to the record mode.
LOGIC FOR RECORD TO PLAYBACK MODE
When the “STOP”, “PAUSE” or “PLAY” button is
pressed, the pin 12 of C751 becomes high level. 0219
turns ON and 0213 (Lch.), 0214 (R ch.) turn ON to mute
the inputs to the record amplifiers. Also, Q712 and
Q713 turn OFF and Q711 turns ON to turn ON Q701,
Q703 (L ch.) and 0702, Q704 (R ch.). Therefore the
outputs from the record amplifiers are muted.
Also, 0505 turns OFF and 0506 turns ON to make the
pin 5 of {C501 low level. Therefore the mode is switched
to the playback mode.

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