Sony HCD-EP303 User manual

HCD-EP303
US Model
Canadian Model
AEP Model
UK Model
E Model
Australian Model
SERVICE MANUAL
COMPACT DISC DECK RECEIVER
Sony Corporation
Home Audio Company
Published by Sony Engineering Corporation
9-873-621-02
2002K1600-1
© 2002.11
HCD-EP303 is the amplifler, CD
player, tape deck and tuner section in
CMT-EP303.
SPECIFICATIONS
Ver 1.1 2002. 11
CD Model Name Using Similar Mechanism HCD-EP30/EP40
SECTION CD Mechanism Type CS-21SC-1280
TAPE DECK Model Name Using Similar Mechanism HCD-EP30/EP40
SECTION Tape Transport Mechanism Type TCM125-2
— Continued on next page —
Amplifier section
AUDIO POWER SPECIFICATIONS:
(U.S.A. model only)
POWER OUTPUT AND TOTAL
HARMONIC DISTORTION:
with 4 Ωloads both channels driven, from 120
- 10,000 Hz; rates 6 W per channel minimum
RMS power, with no more than 10% total
harmonic distortion from 250 mW to rated
output.
Canadian model:
Continuous RMS power output (reference)
6 + 6 W
(4 Ωat 1 kHz, 10% THD)
European model:
DIN power output (rated) 4.5 + 4.5 W
(4 Ωat 1 kHz, DIN)
Continuous RMS power output (reference)
6 + 6 W
(4 Ωat 1 kHz, 10% THD)
Music power output (reference)
13 + 13 W
Other model:
The following measured at AC 230 V or AC 120 V,
50/60 Hz
DIN power output (rated) 4.5 + 4.5 W
(4 Ωat 1 kHz, DIN)
Continuous RMS power output (reference)
6 + 6 W
(4 Ωat 1 kHz, 10% THD)
Outputs
PHONES: Accepts headphones of
(stereo mini jack) 8 Ωor more
SPEAKER: Accepts impedance of 4 to
16 Ω
CD player section
System Compact disc and digital
audio system
Laser Semiconductor laser
(λ=780 nm)
Emission duration:
continuous
Frequency response 20 Hz - 20 kHz (±0.5 dB)
Tape player section
Recording system 4-track 2-channel stereo
Frequency response 50 - 13 000 Hz (±3 dB),
using Sony TYPE I
cassette

2
HCD-EP303
TABLE OF CONTENTS
Tuner section
FM stereo, FM/AM superheterodyne tuner
FM tuner section
Tuning range 87.5 - 108.0 MHz
Antenna FM lead antenna
Intermediate frequency 10.7 MHz
AM tuner section
Tuning range
Pan-American model: 530 - 1 710 kHz
(with the interval set at
10 kHz)
531 - 1 602 kHz
(with the interval set at
9 kHz)
European model: 531 -1 602 kHz
(with the interval set at
9 kHz)
Other models: 531 - 1 602 kHz
(with the interval set at
9 kHz)
530 - 1 710 kHz
(with the interval set at
10 kHz)
Antenna Built-in ferrite bar antenna
Intermediate frequency 450 kHz
General
Power requirements
North American model: 120 V AC, 60 Hz
European model: 230 V AC, 50/60 Hz
Australian model: 230 V AC, 50/60 Hz
Mexican model: 120 V AC, 60 Hz
Argentine model: 220 - 230 V AC, 50/60 Hz
Other models: 230 V AC, 50/60 Hz
Power consumption
U.S.A. model: 25 W
Canadian model: 25 W
European model: 30 W
0.5 W (in the standby
mode)
Other models: 30 W
Dimensions (w/h/d):
Approx. 145 ×240 ×252 mm
Mass: Approx. 2.9 kg
Design and specifications are subject to change
without notice.
1. SERVICING NOTES ······················································ 4
2. GENERAL ·········································································· 5
3. DISASSEMBLY ································································ 7
3-1. Front Panel Section······················································· 7
3-2. MAIN Board ································································· 8
3-3. Tape Mechanism Deck (TCM125-2) ··························· 8
3-4. POWER Board, Power Transformer ···························· 9
3-5. DISPLAY Board, HEADPHONE Board····················· 9
3-6. CD Cabinet Section ··················································· 10
3-7. CD Mechanism Deck (CS-21SC-1280)····················· 10
3-8. Cassette Lid ······························································· 11
4. MECHANICAL ADJUSTMENTS ····························· 12
5. ELECTRICAL ADJUSTMENTS ······························· 12
6. DIAGRAMS······································································ 16
6-1. Circuit Boards Location·············································· 16
6-2. Block Diagrams ·························································· 18
6-3. Printed Wiring Board MAIN Section ························ 21
6-4. Schematic Diagram MIAN Section (1/2) ·················· 22
6-5. Schematic Diagram MIAN Section (2/2) ·················· 23
6-6. Printed Wiring Board CASSETTE Section ··············· 24
6-7. Schematic Diagram CASSETTE Section ·················· 24
6-8. Printed Wiring Board DISPLAY Section ·················· 25
6-9. Schematic Diagram DISPLAY Section ····················· 26
6-10. Printed Wiring Board POWER Section ····················· 27
6-11. Schematic Diagram POWER Section ························ 28
6-12. IC Pin Function Description ······································· 31
7. EXPLODEDVIEWS ······················································ 32
7-1. Cabinet Section ··························································· 32
7-2. Front Panel Section -1 ················································ 33
7-3. Front Panel Section -2 ················································ 34
7-4. CD Cabinet Section ···················································· 35
8. ELECTRICAL PARTS LIST······································· 36

3
To Exposed Metal
Parts on Set
0.15 µF1.5 kΩ
AC
Voltmeter
(0.75 V)
Earth Ground
Fig.A. Using anAC voltmeter to checkAC leakage.
This appliance is classified as a CLASS 1 LASER product. The
CLASS 1 LASER PRODUCT MARKING is located on the rear
exterior.
The following caution label is located inside the unit.
CAUTION
Use of controls or adjustments or performance of procedures
otherthanthosespecifiedherein may result in hazardous radiation
exposure.
HCD-EP303
SAFETY-RELATED COMPONENTWARNING!!
COMPONENTS IDENTIFIED BY MARK 0OR DOTTED LINEWITH
MARK 0ON THE SCHEMATIC DIAGRAMS AND INTHE PARTS
LIST ARE CRITICAL TO SAFE OPERATION. REPLACE THESE
COMPONENTS WITH SONY PARTS WHOSE PART NUMBERS
APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLEMENTS
PUBLISHED BY SONY.
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!
LES COMPOSANTS IDENTIFÉS PAR UNE MARQUE 0SUR LES
DIAGRAMMES SCHÉMATIQUES ET LA LISTE DES PIÈCES SONT
CRITIQUES POUR LA SÉCURITÉ DE FONCTIONNEMENT. NE
REMPLACER CES COMPOSANTS QUE PAR DES PIÈSES SONY
DONT LES NUMÉROS SONT DONNÉS DANS CE MANUEL OU
DANS LES SUPPÉMENTS PUBLIÉS PAR SONY.
Notes on chip component replacement
•Never reuse a disconnected chip component.
•Notice that the minus side of a tantalum capacitor may be
damaged by heat.
Flexible Circuit Board Repairing
•Keep the temperature of soldering iron around 270˚C
during repairing.
•Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
•Be careful not to apply force on the conductor when soldering
or unsoldering.
SAFETY CHECK-OUT
Aftercorrecting the original serviceproblem,perform the following
safety checks before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs,
screws, and all other exposed metal parts for AC leakage. Check
leakage as described below.
LEAKAGETEST
The AC leakage from any exposed metal part to earth ground and
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microamperes).
Leakage current can be measured by any one of three methods.
1. A commercial leakage tester, such as the Simpson 229 or RCA
WT-540A. Follow the manufacturers’instructions to use these
instruments.
2. A battery-operatedAC milliammeter. The Data Precision 245
digital multimeter is suitable for this job.
3. Measuring the voltage drop across a resistor by means of a
VOM or battery-operatedAC voltmeter. The “limit” indication
is 0.75V, so analog meters must have an accurate low-voltage
scale. The Simpson 250 and Sanwa SH-63Trd are examples
of a passive VOM that is suitable. Nearly all battery operated
digital multimeters that have a 2VAC range are suitable. (See
Fig. A)

4
HCD-EP303 SECTION 1
SERVICING NOTES
•MODEL IDENTIFICATION
– Bottom View –
NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
The laser diode in the optical pick-up block may suffer electrostatic
break-down because of the potential difference generated by the
charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic break-down and also
use the procedure in the printed matter which is included in the
repair parts.
The flexible board is easily damaged and should be handled with
care.
NOTES ON LASER DIODE EMISSION CHECK
The laser beam on this model is concentrated so as to be focused on
the disc reflective surface by the objective lens in the optical pick-
up block. Therefore, when checking the laser diode emission,
observe from more than 30 cm away from the objective lens.
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
1. Press the ?/1 button to the power ON with no disc inserted
and press the CD button.
2. Open the lid for CD.
3. Turn on SW600 as following figure.
4. Confirm the laser diode emission while observing the objecting
lens. When there is no emission,Auto Power Control circuit or
Optical Pick-up is broken.
Objective lens moves up and down five times for the focus
search.
SW600
PART No.
at least 30 mm.
CASSETTE board
MAIN board
HEADPHONE
board
at least 30 mm
heatsink
MODEL PART No.
AEP, UK models 4-235-972-0 <
EXCEPT AEP, UK models 4-241-498-0 <
TO PREVENT ‘TAPE OSCILLATION SOUND AT VOLUME’
MAXIMUM SETTING (W/OTAPE)
Headphone wire dressing:
a.) Draw the wire from Main board to Headphone board along the
bottom side of heatsink.
b.)The wire must be kept away from the top side of Cassette board

5
HCD-EP303
SECTION 2
GENERAL This section is extracted
from instruction manual.
Main unit
R – Z
Remote sensor q;
REPEAT (8)
SHUFFLE (8)
TAPE (12)
TIMER indicator (15)
TUNER (10, 11, 13)
TUNER MEM (10)
TUNING +/– (10, 11)
VOLUME control
ALPHABETICAL ORDER
A – P
Cassette compartment qd (12)
CD 4(8, 9, 13)
Display Window 58, 9, 10)
ENTER/PGM 8, 9, 10, 14)
MEGA BASS (14)
MUSIC MENU 9(14)
PHONES jack
PRESET +/– (10, 11)
BUTTON DESCRIPTIONS
@/1 (power) (6)
CD
.m /M> (go back/go
forward) (8, 9)
u(play/pause) (8, 9)
ZPUSH OPEN/CLOSE (8)
x(stop) (8)
TAPE
M(fast forward) (12)
X(pause) (12, 13)
N(play) (12)
z(recording) (13)
m(rewind) (12)
xZ (stop/eject) (12, 13)
w;
8
ws
qs
2
wa
3
1
6
w;
wd
qa
wh
wd
wf
7
wg
qh
qf
qk
ql
qj
qg

6
HCD-EP303
Setting the clock
1Turn on the system.
2Press CLOCK/TIMER/SLEEP SET on
the remote.
3Press CLOCK/TIMER + or – on the
remote repeatedly to set the clock.
4Press TUNER MEM/ENTER/PGM on the
remote.
The clock starts working.
To adjust the clock
Perform from step 2.
Note
The clock settings are canceled when you disconnect
the power cord or if a power failure occurs.
Remote control
ALPHABETICAL ORDER
A – P
CD/REMAIN (7, 8, 9, 13, 15,
16)
CLOCK/TIMER + (7, 14, 15)
CLOCK/TIMER – (7, 14, 15)
CLOCK/TIMER/SLEEP SET
(7, 14, 15)
MEGA BASS (14)
MUSIC MENU (14)
MUTING (14)
PRESET +/– (10, 11)
R – Z
REPEAT (8)
SHUFFLE (8)
TAPE (12)
TIMER ON/OFF (15)
TUNER/BAND (10, 11, 13)
TUNER MEM/ENTER/PGM
(7, 9, 10, 14, 15)
TUNING + (10, 11)
TUNING – (10, 11)
VOL (volume) +/–
BUTTON DESCRIPTIONS
m(rewind) M(fast forward)
qg (8)
.(go back) >(go forward)
qg (8, 9)
u(play/pause) qh (8, 9)
@/1 (power) 3(6)
x(stop) qj (8, 9, 12)
ql
8
qd
1
qs
qa
q;
qf
6
5
qk
2
4
8
qd
9
7

7
HCD-EP303
SECTION 3
DISASSEMBLY
•The equipment can be removed using the following procedure.
3-6. CD CABINET SECTION
(Page 10)
3-5. DISPLAY BOARD,
HEADPHONE BOARD
(Page 9)
3-1. FRONT PANEL SECTION
(Page 7)
3-3. TAPE MECHANISM DECK
(TCM125-2)
(Page 8)
3-7. CD MECHANISM DECK
(CS-21SC-1280)
(Page 10)
3-8. CASSETE LID
(Page 11)
3-2. MAIN BOARD
(Page 8) 3-4. POWER BOARD,
POWER TRANSFORMER
(Page 9)
SET
3-1. Front Panel Section
8 connector
(CN203)
5 two screws
(+K3
× 5)
3 two screws
(+BTP2.6
× 10)
1 screw
(+BVTP3
× 10)
4 two screws
(+BVTP3
× 10)
5 two screws
(+K3
× 5)
5 two screws
(+K3
× 5)
9 connector
(CN402)
0 connector
(SW600)
qa front panel section
7
2 antenna cover cabine
t
6 claw
Note : Follow the disassembly procedure in the numerical order given.

8
HCD-EP303
3-2. MAIN Board
6 connector
(CN202)
5 connector
(CN201)
4 connector
(CN302)
3 connector
(CN301)
2 connector
(CN101)
1 connector
(CN204)
0 MAIN board
8 claw
7 screw
(+BTP2.6 × 8)
9
3-3. Tape Mechanism Deck (TCM125-2)
4 CASSETTE boar
d
3
1 connector
(CN701)
2 two screws
(+BTP2.6
× 6)
6 two screws
(+BVTP3
× 10)
6 two screws
(+BVTP3
× 10)
7 tape mechanism deck
5 Open the cassette lid.

9
HCD-EP303
3-4. POWER Board, PowerTransformer
9 screw
(+BTP2.6
× 8)
3 screw
(+BVTP3
× 10)
1 screw
(+BVTP3
× 10)
4 four screws
(+BVTP3
× 12)
6 power transformer
5 POWER board
q; power pwb mounting bkt
2 ac cord holder
7 Remove four solderings.
8 Remove four solderings.
rear cabinet assy
3-5. DISPLAY Board, HEADPHONE Board
3 screw
(+PTPWH2.6
× 10)
5 HEADPHONE board
4 reteiner board
2 DISPLAY board
1 seven screws
(+BTP2.6
× 10)

10
HCD-EP303
3-6. CD Cabinet Section
1 two screws
(+BTP2.6
× 8
)
2 CD cabinet section
3-7. CD Mechanism Deck (CS-21SC-1280)
1 two screws
(BVTP3 × 10)
4 CD cover housing
8 vibration proof rubber
(pink)
8 vibration proof rubber
(pink)
6 four fiber washers
5 four pulley screws
8 vibration proof rubber
(orange)
8 vibration proof rubber
(orange)
9 CD mechanism deck (CS-21SC-1280)
6
3
7 two spring clamps
7 two spring clamps
2 Remove the connector.

11
HCD-EP303
3-8. Cassette Lid
1 Push stop/eject key.
4 cassette lid
3 claw
3 claw
2

12
HCD-EP303 SECTION 4
MECHANICAL ADJUSTMENTS SECTION 5 ELECTRICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab : record/playback head pinch roller
erase head rubber belts
capstan idlers
2. Demagnetize the record/playback head with a head
demagnetizer. (Do not bring the head magnetizer close to the
erase head.)
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
Torque Measurement
TapeTension Measurement
Mode Torque Meter Meter Reading
FWD CQ-403A more than 100 g
(more than 3.53 oz)
PRECAUTION
1. Setting
MEGA BASS switch : OFF
TAPE DECK SECTION 0 dB=0.775 V
Test tape
Mode Torque Meter Meter Reading
2.95 – 6.86 mN•m
FWD CQ-102C (30 – 70 g•cm)
(0.42 – 0.97 oz•inch)
0.15 – 5.39 mN•m
FWD CQ-102C (1.5 – 5.5 g•cm)
Back Tension (0.021 – 0.076 oz•inch)
more than 5.89 mN•m
FF CQ-201B (more than 60 g•cm)
(more than 0.83 oz•inch)
more than 5.89 mN•m
REW CQ-201B (more than 60 g•cm)
(more than 0.83 oz•inch)
Type Signal Used for
WS-48A 3 kHz, 0 dB Tape Speed Adjustment
P-4-A063 6.3 kHz, –10 dB Head Azimuth Adjustment
Record/Playback Head Azimuth Adjustment
Procedure:
1. Mode: Playback
level meter
test tape
P-4-A063
(6.3 kHz, –10 dB)
set
HEADPHONE board
PHONES jack (JK401
)
32 Ω
+
–
2. Turn the adjustment screw and check output peaks. If the peaks
do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 1dB of peak.
3. Mode: Playback
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
Screw
position
L-CH
peak
within
1dB
Output
level
L-CH
peak R-CH
peak
within
1dB
Screw
position
R-CH
peak
test tape
P-4-A063
(6.3 kHz, –10 dB)
L-CH
R-CH HEADPHONE board
PHONES jack (JK401)
oscilloscope
VH
++
––
screen pattern
in phase good wrong
45 °
90 °
135 ° 180 °
32 Ω
32 Ω
set

13
HCD-EP303
Tape Speed Adjustment
Setting:
Function: TAPE
Procedure:
1. Playback WS-48A (tape center) in the FWD state.
2. Adjsut the volume in CAPSTAN/REEL motor (M201) so that
the frequency counter reading becomes 3,000 Hz.
Specified Value: 2,910 to 3,090 Hz
3. Confirm that the frequency at the beginning and that at the end
of tape winding are between 2,955 to 3,045 Hz.
Adjustment Location:
frequency counte
r
test tape
WS-48A
(3 kHz, 0 dB)
set
HEADPHONE board
PHONES jack (JK401)
–
+
32
Ω
CAPSTAN/REE
L
motor (M201)
Tape Speed
Adjustment
Adjustment Location: Record/Playback Head.
Note: Refer to “3-8.Cassette Lid” (see page 11)
adjustment screw

14
HCD-EP303
TUNER SECTION 0 dB=1 µV
[AM]
Setting:
Function : TUNER
Band switch : AM
[FM]
Setting:
Function : TUNER
Band switch : FM
•Repeat theprocedures in eachadjustment several times, andthe frequency
coverage and tracking adjustments should be finally done by the trimmer
capacitors.
AM RF signal
generator
30% amplitude
modulation by
400 Hz signal
Output level: as low as possible
Put the lead-wire
antenna close to
the set.
+
–
level meter
set
32 Ω
HEADPHONE board
PHONES jack (JK401
)
FM RF signal
generator
22.5 kHz frequency
deviation by 400 Hz
signal
Output level: as low as possible
+
–
level meter
set
32 Ω
0.01 µ F
MAIN board
FM ANT
HEADPHONE board
PHONES jack (JK401
)
digital voltmeter
100 k Ω
MAIN board
TP10 (FM VT)
TP11 (AM VT)
no mark: Except AEP, UK models
< > : AEP, UK models
AM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
Confirmation 530 kHz 1.5 ± 0.2 V
<531 kHz>
T102 1,710 kHz 7.7 ± 0.3 V
<1,602 kHz> <7.3 ± 0.3 V>
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L110 600 kHz <603 kHz>
TC102 1,400 kHz <1,404 kHz>
FM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L104 87.6 MHz 2.1 ± 0.2 V
Confirmation 108 MHz 7.0 ± 0.4 V
FMTRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L103 89.9 MHz
TC101 105.9 MHz
Adjustment Location: MAIN board (See page 15)

15
HCD-EP303
Adjustment Location and Connecting Points
– MAIN BOARD (Component Side) –
L104 FM Frequency
Coverage Adjustment
T102
AM Frequency Coverage Adjustmen
t
AM Tracking
{
L110
Adjustment TC102
FM Tracking TC101
Adjustment
{
L103
– MAIN BOARD (Conductor Side) –
TP10
(FM VT)
TP11
(AM VT)
IC101

16
HCD-EP303 SECTION 6
DIAGRAMS
6-1. Circuit Boards Location
MAIN board
LED board
HEADPHONE board
CASSETTE board DISPLAY board
POWER boar
d

1717
HCD-EP303
Note on Schematic Diagram:
• All capacitors are in µF unless otherwise noted. p:pF.
50 WV or less are not indicated except for electrolytics
and tantalums.
•All resistors are in Ωand 1/4W or less unless otherwise
specified.
•2: nonflammable resistor.
•C: panel designation.
Note on PrintedWiring Board:
•W: indicates side identified with part number.
•: Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
•Indication of transistor
•A: B+ Line.
•H: adjustment for repair.
•Voltagesare takenwithaVOM(Input impedance10MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
•Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal produc-
tion tolerances.
no mark : FM
<>:CD (STOP)
•Circled numbers refer to waveforms.
•Signal path.
F: FM
f: AM
E: PB (TAPE)
a: REC (TAPE)
J: CD PLAY
•Abbreviation
E51 : Chilean and Peruvian model.
MY : Malaysia model.
SP : Singapore model.
AR : Argentine model.
MX : Mexican model.
AUS:Australian model.
Note:
The components identi-
fied by mark 0or dotted
linewithmark 0are criti-
cal for safety.
Replace only with part
number specified.
Note:
Lescomposantsidentifiés par
une marque 0sont critiques
pour la sécurité.
Ne les remplacer que par une
piéce portant le numéro
spécifié.
•WAVEFORMS
– MAIN Board – – CASSETTE Board – – DISPLAY Board –
1IC102 ws (XOUT)
3.4 Vp-p
139 ns
1 V/DIV, 40 ns/DIV
2Q705 (Collector)
(RECORD mode)
2 V/DIV, 4 µ s/DIV
3IC601 tl (X2)
1 V/DIV, 100 ns/DIV
6.0 Vp-p
12.4
µ s5.2 Vp-p
167 ns
B
These are omitted.
CE

1818
HCD-EP303
6-2. Block Diagrams
TUNER/TAPE DECK Section
: FM
: AM
• Signal Path
• R-CH is omitted due to same as L-CH.
: PB(TAPE)
: REC(TAPE)
9
13
12
11
1
3
105
15
7
7
16
18
19
20
15
8
11 12
6
4
5
3
7
2
4
3
1 22
Q101
FM OSC
BUFFER
Q102
BAND
SWITCH
Q703
MUTING
CONTROL
SWITCH
Q704
MUTING
CONTROL
SWITCH
Q702
MUTING
Q104
AMP
Q601
BUFFER
BPF
ANT1
AMRF
IN
AM
OSC
24 FMRF
IN
22 FMRF
OUT
FM
OSC
20
QUAD
AM
OSC BUFFER
FM
ANT
L110
AM ANT
D105 T102
AM OSC
L103
FM RF
D103
D104 L104
FM OSC
F101
10.7MHz
T103
X101
10.7MHz
PD
LRFIN
LPFOUT
FMIN
AMIN
BO1
IO1
IFIN
DO
DI
CL
CE
IC102
FM/AM PLL
X102
7.2MHz
XIN XOUT
AM MIX
FM MIX
FM DET
SD
AM/FM
IF
BUFFER
AM IF
16
17
L
R
IC101
AM/FM IF AMP,
MIX, MPX, DET, OSC
REC
BIAS
OSC
Q706
SW701
(3/6)
REC
PB
R-CH
L
R
T701
REC BIAS
ERASE HEAD
REC/PB HEAD AMP
ALC CONT
ALC IN1
IN1 OUT1
M
41 36 37 47 38
60
(CAPSTAN/REEL)
STEREO
45
SYNCRO
TUNER SD
ST
PLLDI
PLLCE PLLCL
PLLDI
PLLCE PLLCL
STOUT
SIG
SIG
ST
PLLDI
PLLCE
PLLCE
PLLCL
STOUT
AMP SECTION
B
AMP SECTION
C
AMP SECTION
D
DISPLAY SECTION
E
AMP SECTION A
IC701
ALC REC/PB AMP
IC601 (1/3)
SYSTEM CONTROLLER
R-CH
TUNER
L-CH
PL
RL
DC_12V
(MAGNET)
COTR
S201
(PLAY)
+
TC102
TC101
FM FREQUENCY
COVERAGE
AM FREQUENCY
COVERAGE
AM TRACKING
FM TRACKING
F102
PLLDO SELECT
DISPLAY SECTION
F
M201
SW701
(4/6)
PB
REC
SW701
(6/6)
PB
REC
SW701
(5/6)
REC
PB

1919
HCD-EP303
AMP Section
• Signal Path
• R-ch is omitted due to same as L-ch.
: FM
: CD
: PB(TAPE)
: REC(TAPE)
IC203
FUNCTION SELECT SWITCH,
ELECTRONIC VOLUME
Q301,302
MUTING
Q314
MUTING
CONTROL
SWITCH
Q201
REC AMP
Q206
MEGA BASS
R-CH
R-CH
R-CH
RL
LTCOM
LTOUT
LVRIN
LVROUT
L3
CD
CD L
CD L
CD R
CDDAT
CDCLK
CDRS
TUNER
L-CH
PL
L4
TUNER
L2
TAPE
DI CE
4652
BASS BOOST
MUTE
MUTE
1
10
9
11
15 16
212
11 5
3
3
4
40
DATA
34
CD-RESET
42
CD CLOCK
61
CD DATA
D332
D333
+
+
+
+
–
+
–
SPEAKER
(IMPEDANCE
USE 4Ω)
L
R
PHONES
SPK301
JK401
IC601 (2/3)
SYSTEM CONTROLLER
D
A
B
C
CL
14
39
CLOCK
48
CE
TAPE
SECTION
TUNER
SECTION
TAPE
SECTION
TAPE
SECTION
HDISPLAY
SECTION GDISPLAY SECTION
CD BLOCK
30
TAPE
COTR
DATA
CLOCK
IC301
POWER AMP

2020
HCD-EP303
DISPLAY/POWER Section
LD621
LIQUID
CRYSTAL
DISPLAY
COM0
ı
COM3
KEY R0
ı
KEY R3
Q1
ı
Q7
X
AMP SECTION
H
X
TUNER SECTION
E
X
AMP SECTION
G
X
TUNER SECTION
F
S0
ı
S31
44 REMOTE
X602
6MHz
58 X1
59 X2
31CD
IC601 (3/3)
SYSTEM CONTROLLER,
LIQUID CRYSTAL DISPLAY DRIVER
29TUNER
51PSW
32TIMER STATUS
35SURROUND
6312/24H SELECT
68CPU RESET
6V
CD 8V
Q116
B+ SWITCH
Q602
SWITCH
Q603
SWITCH
Q604
SWITCH
TUNER +9V
D317
D307
D310
D308
D311
Q308, 309
+8V
REGULATOR
Q313
+9V
REGULATOR
Q312
+6V
REGULATOR
ZD401
+6V
REGULATOR
9V
D401 – 404
RECT
D411 – 414
RECT
Q401,402
POWER ON/OFF
RELAY DRIVE
Q310,311
REGULATOR
CONTROL SWITCH
TR402
POWER
TRANSFORMER
(SUB)
D405 – 408
RECT
RL401
AC IN
TR401
POWER
TRANSFORMER
(MAIN)
REM601
REMOTE CONTROL
RECEIVER
1
53
SW601 - 615, 621, 622
KEY MATRIX
DPSW2/SLEND
IC301
(POWER AMP)
IC603
RESET SIGNAL
GENERATOR
D611 - 615
2
3
4 - 7,
14 -12
IC602
KEY CONTROL
DATA
CLOCK
SW600
ZPUSH
OPEN/CLOSE
D607
D608
D603
D618
D648
D619
TIMER
64-67
21-24
69-80,
1 -20
DC_15V
DC_12V
MUTE
PLLCE
6V
10kHz
9kHz
SW301
(AM FREQ STEP)
D1 - D3
(LCD BACK LIGHT)