Sony HCD-EP50 User manual

SERVICE MANUAL
COMPACT DISC DECK RECEIVER
US Model
Canadian Model
AEP Model
UK Model
E Model
Chinese Model
HCD-EP50
Ver 1.1 2001.09
HCD-EP50istheamplifier, CD player, tape
deck and tuner section in CMT-EP50.
9-873-897-12 Sony Corporation
2001I0500-1 Home Audio Company
C2001.9 ShinagawaTec Service Manual Production Group
SPECIFICATIONS
CD Model Name Using Similar Mechanism HCD-EP30
Section CD Mechanism Type CS-21SC-1280
TAPE Model Name Using Similar Mechanism NEW
Section Tape Transport Mechanism Type CRL3439
AUDIO POWER SPECIFICATIONS:
(US model only)
POWER OUTPUT AND TOTAL
HARMONIC DISTORTION:
with 8 Ωloads both channels driven, from 120
- 10,000 Hz; rates 12 W per channel minimum
RMS power, with no more than 10% total
harmonic distortion from 250 mW to rated
output.
Amplifier section Canadian model:
Continuous RMS power output (reference)
12 + 12 W
(8 Ωat 1 kHz, 10% THD)
AEP, UK models:
DIN power output (rated) 11 + 11 W
(8 Ωat 1 kHz, DIN)
Continuous RMS power output (reference)
12 + 12 W
(8 Ωat 1 kHz, 10% THD)
Music power output (reference)
27 + 27 W
Other models:
The following measured at AC 230 V, 50/60 Hz
DIN power output (rated) 11 + 11 W
(8 Ωat 1 kHz, DIN)
Continuous RMS power output (reference)
12 + 12 W
(8 Ωat 1 kHz, 10% THD)
Outputs
PHONES: Accepts headphones of
(stereo mini jack) 8 Ωor more
SPEAKER: Accepts impedance of 8 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
Tuner section
FM stereo, FM/AM superheterodyne tuner
FM tuner section
Tuning range 87.5 - 108.0 MHz
Antenna FM lead antenna
Antenna terminal 75 Ωcoaxial
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 - 1 710 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 AM loop antenna
Antenna terminal External antenna terminal
Intermediate frequency 450 kHz
General
Power requirements
US, Canadian models: 120 V AC, 60 Hz
AEP, UK models: 230 V AC, 50/60 Hz
Mexican model: 120 V AC, 60 Hz
Argentine model: 220 V AC, 50/60 Hz
Hong Kong model: 230 V AC, 50/60 Hz
Chinese model: 220 V AC, 50/60 Hz
Other models: 230 V AC, 50/60 Hz
Power consumption
US model: 35 W
Canadian model: 35 W
AEP, UK models: 40 W
0.9 W (in the standby
mode)
Other models: 40 W
Dimensions (w/h/d):
Approx. 145 ×238 ×234 mm
Mass: Approx. 3.4 kg
Supplied accessories: AM loop antenna (1)
Remote Commander (1)
Batteries (2)
FM lead antenna (1)
Speaker pads (8)
Design and specifications are subject to change
without notice.

2
HCD-EP50
TABLE OF CONTENTS
1. SERVICING NOTES ................................................ 4
2. GENERAL ................................................................... 5
3. DISASSEMBLY
3-1. Disassembly Flow ........................................................... 7
3-2. Front Panel Section ......................................................... 8
3-3. MAIN Board ................................................................... 8
3-4. CD Cabinet Section......................................................... 9
3-5. CD Mechanism Deck (CS-21SC-1280) ......................... 9
3-6. Tape Mechanism Deck (CRL3439) ................................ 10
3-7. Cassette Lid ..................................................................... 10
4. MECHANICAL ADJUSTMENTS....................... 11
5. ELECTRICAL ADJUSTMENTS......................... 11
6. DIAGRAMS
6-1. Block Diagram – TUNER Section – ............................. 15
6-2. Block Diagram – TAPE DECK Section – ..................... 16
6-3. Block Diagram – MAIN Section – ................................ 17
6-4. Block Diagram
– DISPLAY/POWER SUPPLY Section – ...................... 18
6-5. Note for Printed Wiring Boards and
Schematic Diagrams ....................................................... 19
6-6. Schematic Diagram – FM TUNER Section – ............... 19
6-7. Schematic Diagram – MAIN Board (1/3) – .................. 20
6-8. Schematic Diagram – MAIN Board (2/3) – .................. 21
6-9. Schematic Diagram
– MAIN (3/3)/HEADPHONE Boards – ......................... 22
6-10. Printed Wiring Boards
– MAIN/HEADPHONE Boards –.................................. 23
6-11. Printed Wiring Board – DISPLAY Board – .................. 24
6-12. Schematic Diagram – DISPLAY Board – ..................... 25
6-13. Printed Wiring Board – POWER Board – ..................... 26
6-14. Schematic Diagram – POWER Board –........................ 27
6-15. IC Pin Function Description ........................................... 31
7. EXPLODED VIEWS
7-1. Cabinet Section ............................................................... 33
7-2. Front Panel Section-1...................................................... 34
7-3. Front Panel Section-2...................................................... 35
7-4. CD Cabinet Section......................................................... 36
8. ELECTRICAL PARTS LIST ............................... 37

3
HCD-EP50
Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
Flexible Circuit Board Repairing
• Keep the temperature of the soldering iron around 270 ˚C dur-
ing 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.
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous ra-
diation exposure.
SAFETY CHECK-OUT
After correcting the original service problem, perform the follow-
ing safety check 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.
LEAKAGE TEST
TheAC 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-operated AC voltmeter. The “limit” indica-
tion is 0.75 V, so analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex-
amples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2VAC range are suit-
able. (See Fig. A)
Fig. A. Using an AC voltmeter to check AC leakage.
1.5 k Ω 0.15 µF
AC
voltmete
r
(0.75 V)
To Exposed Metal
Parts on Set
Earth Ground
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!
LES COMPOSANTS IDENTIFIÉS PAR UNE MARQUE 0
SUR LES DIAGRAMMES SCHÉMATIQUES ET LA LISTE
DES PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ
DE FONCTIONNEMENT. NE REMPLACER CES COM-
POSANTS QUE PAR DES PIÈCES SONY DONT LES
NUMÉROS SONT DONNÉS DANS CE MANUEL OU
DANS LES SUPPLÉMENTS PUBLIÉS PAR SONY.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK 0OR DOTTED
LINE WITH MARK 0ON THE SCHEMATIC DIAGRAMS
AND IN THE 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 PUB-
LISHED BY SONY.
The following caution label is located inside the unit.
This appliance is classified as
a CLASS 1 LASER product.
The CLASS 1 LASER
PRODUCT MARKING is
located on the rear exterior.
Ver 1.1

4
HCD-EP50
NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
The laser diode in the optical pick-up block may suffer electro-
static 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 emis-
sion, observe from more than 30 cm away from the objective lens.
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
1. Press the I/1button to the power ON with no disc inserted
and press the [CD] button.
2. Open the lid for CD.
3. Turn on SW300 as following figure.
4. Confirm the laser diode emission while observing the object-
ing lens. When there is no emission, Auto Power Control cir-
cuit or Optical Pick-up is broken.
Objective lens moves up and down five times for the focus
search.
SECTION 1
SERVICING NOTES
• MODEL IDENTIFICATION
– Bottom View –
MODEL PART No.
AEP and UK models 4-235-177-0[]
US and Canadian models 4-235-179-0[]
Singapore and Hong Kong models 4-235-180-0[]
Mexican model 4-235-182-0[]
Argentina model 4-235-183-0[]
Chinese model 4-238-634-0[]
SW300
PA R T N o.
Ver 1.1

5
HCD-EP50
Cassette compartment qj (13)
CD 4(8, 9, 14)
DISPLAY wf (9, 11)
Display Window 5(8, 9, 10)
ENTER ql (7, 9, 10, 12)
ISS 0(14)
MEGA BASS 8(16)
MONO STEREO 0(11)
MUSIC MENU 9(16)
PHONES jack wa
PLAY MODE w; (8, 9)
PRESET +/— qk (10, 11, 12)
RDS (European model only)/DIR
w; (12, 13, 14, 15)
Remote sensor wg
TAPE 3(13)
TIMER indicator 2(15, 18)
TUNER 6(10, 11, 14)
TUNER MEM ql (10)
TUNING + qf (10, 11, 12, 15)
TUNING — qg (10, 11, 12, 15)
VOLUME control qd
1 2 3456 7
8
9
q;
qh
qg
qf
qd
qs
qa
qk
ql
w;
wa
ws
wg
wf
wd
qj
BUTTON DESCRIPTIONS
@/1 (power) 1(7, 11, 15, 18)
CD
.m(go back) qg (8, 9)
M>(go forward) qf (8, 9)
nN (play) qa (8, 9)
X(pause) wd (8)
ZPUSH OPEN/CLOSE 7(8)
x(stop) qs (8, 9)
TAPE
M> (fast forward) qf (13)
X(pause) wd (13)
nN (play) qa (13, 14, 15)
z (recording) ws (14, 15)
.m (rewind) qg (13)
ZPUSH OPEN/CLOSE qh (13)
x(stop) qs (13, 14)
SECTION 2
GENERAL This section is extracted from
instruction manual.
LOCATION OF CONTROLS
–Front Panel –

6
HCD-EP50
Setting the time
1Turn on the system.
2Press CLOCK/TIMER on the remote.
When you set the clock for the first time, go
to step 5.
3 Press CLOCK/TIMER on the remote
repeatedly until SET CLK appears in
the display.
4 Press TUNER MEM/ENTER on the
remote.
5 Press TUNING/CLOCK/TIMER + or — on
the remote repeatedly to set the hour.
6 Press TUNER MEM/ENTER on the
remote.
7 Press TUNING/CLOCK/TIMER + or — on
the remote repeatedly to set the minute.
8 Press TUNER MEM/ENTER on the
remote.
To reset the system clock
Start over from step 1.
Note
The clock settings are canceled when you disconnect
the power cord or if a power failure occurs.
CD 3(8, 9, 14)
CLOCK/TIMER qg (7, 15, 17)
DISPLAY qh (9, 11)
MEGA BASS 2(16)
MUSIC MENU wa (16)
PLAY MODE/RDS (European
model only)/DIR qj (8, 9, 12,
13, 14, 15)
PRESET +/—qk (10, 11)
REPEAT 7(8)
SLEEP qd (17)
TAPE w; (13)
TIMER ON/OFF qf (15, 18)
TUNER/BAND 5(10, 11, 14)
TUNER MEM/ENTER 6(7, 9,
10, 12, 15, 17, 18)
TUNING/CLOCK/TIMER +/—
ql (7, 10, 11, 12, 15, 17, 18)
VOLUME +/—4
BUTTON DESCRIPTIONS
M(fast forward) >(go
forward) 0(8, 9, 13)
.(go back) m(rewind) qa
(8, 9, 13)
X(pause) qs (8, 13)
nN (play) 8(8, 9, 13, 14, 15)
`/1(power) 1(7, 11, 15, 18)
x(stop) 9(8, 9, 13, 14)
Remote Control
1234
5
6
7
8
9
q;
qa
qs
qg
qd
qf
qh
qj
qk
ql
w;
wa

HCD-EP50
7
•This set can be disassembled in the order shown below.
3-1. DISASSEMBLY FLOW
SECTION 3
DISASSEMBLY
3-4. CD CABINET SECTION
(Page 9)
3-2. FRONT PANEL SECTION
(Page 8)
3-6. TAPE MECHANISM DECK
(CRL3439)
(Page 10)
3-5. CD MECHANISM DECK
(CS-21SC-1280)
(Page 9)
3-7. CASSETTE LID
(Page 10)
3-3. MAIN BOARD
(Page 8)
SET

HCD-EP50
8
3-3. MAIN BOARD
Note: Follow the disassembly procedure in the numerical order given.
3-2. FRONT PANEL SECTION
6 connector
(CN3)
3 two screws
(+K3
× 5)
1 two screws
(BTP2.6
× 10)
2 two screws
(BVTP3
× 10
)
3 two screws
(+K3
× 5)
3 two screws
(+K3
× 5)
7 connector
(CN601)
8 connector
(SW300)
9 front panel section
5
4 claw
6 connector
(CN14)
6 connector
(CN15)
5 connector
(CN5)
4 connector
(CN201)
3 connector
(CN7)
2 connecto
r
(CN11)
1 connector
(CN9)
1 connector
(CN4)
9 MAIN board
7 screw
(+BTP2.6
× 8)
8

HCD-EP50
9
3-4. CD CABINET SECTION
3-5. CD MECHANISM DECK (CS-21SC-1280)
1 two screws
(BTP2.6
× 8
)
2 CD cabinet section
1 two screws
(BVTP3 × 10)
2 plastic cover
7 vibration proof rubber
(pink)
7 vibration proof rubber
(pink)
4 four fiber washers
3 four pulley screws
7 vibration proof rubber
(ORG)
7 vibration proof rubber
(ORG)
8 CD mechanism deck (CS-21SC-1280)
5
6 two spring clamps
6 two spring clamps

HCD-EP50
10
3-6. TAPE MECHANISM DECK (CRL3439)
3-7. CASSETTE LID
1 two screws
(BVTP3
× 10)
1 two screws
(BVTP3
× 10
)
2 tape mechanism deck
(CRL3439)
1 Open the cassette lid.
3 cassette lid
2 claw
2 claw

11
HCD-EP50
SECTION 4
MECHANICAL ADJUSTMENTS SECTION 5 ELECTRICAL ADJUSTMENTS
Tape Speed Adjustment
Setting:
Function: TAPE
Procedure:
1. Playback WS-48B (tape center) in the FWD state.
2. Adjsut the volume in CAPSTAN/REEL motor so that the fre-
quency counter reading becomes 3,000 Hz.
Specified Value: 2,970 to 3,030 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:
PRECAUTION
1. Setting
MEGA BASS switch : OFF
TAPE DECK SECTION 0 dB=0.775 V
Test tape
Type Signal Used for
WS-48B 3 kHz, 0 dB Tape Speed Adjustment
P-4-A100 10 kHz, –10 dB Head Azimuth Adjustment
frequency counter
test tape
WS-48B
(3 kHz, 0 dB)
set
MAIN board
SPEAKER terminal (CN17
)
–
+
47 kΩ
CAPSTAN/REEL
motor
Tape Speed
Adjustment
Mode Tension Meter Meter Reading
FWD CQ-403A more than 100 g
(more than 3.53 oz)
• Tape Tension Measurement
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 demagne-
tizer. (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
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)

12
HCD-EP50
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 (FWD)
4. Repeat step 1 to 3 in playback (REV) mode.
5. 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-A100
(10 kHz, –10 dB)
L-CH
R-CH
MAIN board
SPEAKER terminal (CN17)
oscilloscope
VH
++
––
screen pattern
in phase
good wrong
45 °90 °135 °180 °
47 kΩ
47 kΩ
set
Record/Playback Head Azimuth Adjustment
Procedure:
1. Mode: Playback (FWD)
level meter
test tape
P-4-A100
(10 kHz, –10 dB)
set
MAIN board
SPEAKER terminal (CN17)
47 kΩ
+
–
Adjustment Location:Record/Playback Head.
Note: Refer to “3-7. CASSETTE LID”(see page 10)

13
HCD-EP50
no mark: EXCEPTAEP, UK, Chinese models
< > : AEP, UK, Chinese models
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter
T1 450 kHz
AM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
T8 530 kHz 1.3 ±0.1 V
<531 kHz>
Confirmation 1,710 kHz 7.8 ±0.5 V
<1,602 kHz> <7.1 ±0.5 V>
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
T6 603 kHz
TC1 1,404 kHz
FM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L901 87.5 MHz 2.4 ±0.1 V <1.4 to 1.6 V>
<Confirmation>
Confirmation 108 MHz 6.8 ±0.5 V <7.3 to 8.5 V>
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L902 90.1 MHz
TC901 106.1 MHz
(EXCEPT AEP, UK, Chinese models)
Adjustment Location: MAIN board (See page 14)
TUNER SECTION 0 dB=1 µV
[AM]
Setting:
Function : TUNER
Band switch: AM
[FM]
Setting:
Function : TUNER
Band switch: FM
• Repeat the procedures in each adjustment several times, and the
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
MAIN board
SPEAKER terminal (CN17
)
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 µF
MAIN board
FM ANT
MAIN board
SPEAKER terminal (CN17
)
digital voltmeter
100 kΩ
MAIN board
TP (FM VT)
TP (AM VT)
Ver 1.1

14
HCD-EP50
Adjustment Location and Connecting Points
–MAIN BOARD (Component Side) –
T8
AM Frequency
Coverage Adjustment
T1
AM IF Adjustment
AM Tracking Adjustment
{
TC1
T6
–MAIN BOARD (Conductor Side) –
TP
(FM VT)
TP
(AM VT)
U1
U2
L902
}
FM Tracking Adjustment
TC901
L901 FM Frequency Coverage Adjustment

HCD-EP50
1515
AM
RF AMP
AM
OSC
AM
MIX
L. P. F
FM/AM PLL
U2
AM/FM
IF BUFFER
DECODER
• SIGNAL PATH
: FM
: AM
X2
7.2MHz
AMIN
IFIN
IF-BUFF MUTE AM/FM VCO-STOP
IO1
AOUT
AIN
FMIN
20
1
14 13 18
SWALLOW
COUNTER
UNIVERSAL
COUNTER
CCB
INTERFACE
REFERENCE
DIVIDER
UNLOCK
DETECT
12 BIT
PROGRAMMABLE
DIVIDER
PHASE
DETECTOR/
CHARGE PUMP
SHIFT REGISTER & LATCH
1/2
DI
CL
CE
DO
DA IN
STATION
STEREO
FM ON/OFF
ST/BEAT
TU-L
R-CH
R-CH
OUT L
AMP-
IN L
AMP-
OUT L
OUT R
RCLK
RDATA
RCLK
RDATMUX
TU-R
CLOCK
PLL CE
DA OUT
PD
XIN
XOUT
3
4
2
5
11
BO1
61017 16
• R-ch is omitted due to same as L-ch.
CN12
CN13 U4
FM FRONT-END
CF2
10.7MHz
T6
AM RF
T8
AM OSC
D5
CF5
10.7MHz
CF3
10.7MHz
1
5
7
AM-RF
-IN AM-IF
FM-IN
FM-DET
OUT MPX-IN
AM-DET OUT
AM-MIX
AM-OSC
OSC.BUFF FM-SD.ADJ
8
123
2
30
427
29
TC1
DETAM IF
AGC
CF4
450kHz
FM
DET
FM IF
PLL 57kHz
RDS/ARI
24
22
20
21 19 17
MUTING
13 1514
TUNED
6
STEREO
7
BUFFER
Q5 4BIPHASE
DECODER
PLL
1187.5Hz
16
2
X304
4.332MHz
RDS DECODER
IC305
FM/AM IF AMP,
AM RF AMP/MIX/OSC,
FM/AM DET, MPX
U1
14
13
XI
XO
E(Page 17)
A(Page 18)
C(Page 16)
D(Page 18)
B(Page 17)
FM ANT
75Ω
COAXIAL
AM ANT
AM FREQUENCY
COVERAGE
T8
AM TRACKING
T6, TC1
AM IF
T1
FM DET
9
T5
FM DET
L. P. F.
T4
L. P. F.
T2
ANTI-ALIASING
FILTER COMPARATOR DEFERENTIAL DECODER
FM/AM BAND
SELECT SWITCH
Q3
STEREO/MONO
SWITCHING
Q17
OSC CLOCK
FM IF AMP
Q2
(AEP, UK, Chinese)
(AEP, UK)
(EXCEPT AEP, UK, Chinese)
1FM RF
AMP
PHASE
DETECTOR/
CHARGE PUMP
FM RF
IN
MIX
OUT 3
13
FM
OSC
FM OSC
BUFFER
Q901
15
FM RF
OUT
FM MIX
FM OSC
D905 D906
TC901
B. P. F.
BPF901
T901
FM IFT
L901
FM OSC
L902
FM RF
FM FREQUENCY
COVERAGE
L901
FM TRACKING
L902, TC901
FM RF AMP/MIX/OSC
IC901
SECTION 6
DIAGRAMS
6-1. BLOCK DIAGRAM – TUNER Section –
Ver 1.1

HCD-EP50
1616
•SIGNAL PATH
: RECORD
: TAPE PLAY
Q5
REC/PB SWITCHING
U12
ALC,
REC/PB AMP
U13
R-CH
Q36
R-CH
L-CH
HPRE101 (1/2)
(RECORD/PLAYBACK)
R-CH R-CH
14
Q1
4
STR 1
2
6
7
3
4
4
8
7 9
(PROTECT (FWD) DETECT)
(PROTECT (REV) DETECT)
(TAPE DETECT)
(CrO
2 DETECT)
REC/PB
SWITCH
Q34
REC/PB
SWITCH
Q30
AMP GAIN
CONTROL
Q28
ALC
CONTROL
Q8
ALC
BIAS
TRAP
CAPSTAN/REEL
MOTOR DRIVE
Q37, 39
SENSORA
18
AMS
24
SEL14
98
SEL15
SEL12
96
SEL10
94
BIAS OSC
L5
9V
+5V
REC BIAS
SWITCH
Q32, 33
M
(CAPSTAN/REEL)
Q7
12
TRIGGER
PLUNGER DRIVE
Q38, 40
(TRIGGER PLUNGER)
Q3
6
LED
DRIVE
Q305
D313
SW318
(MONO STEREO)
CAPSTAN/REEL MOTOR CONTROL,
TRIGGER PLUNGER CONTROL,
REC BIAS CONTROL
U15
SYSTEM CONTROLLER
IC301 (1/3)
R-CH
R-CH
R-CH
R-CH
R-CH
R-CH
(HEAD POSITION DETECT)
STROBE
44
DATA 2
CLK 3
Q8 11
Q6
CD-EN
TU-EN
ST/BEAT
DA IN
CLOCK
13
D305 D306 D308
D29
D50 D4
D32
Q4
7
LED
DRIVE
Q304
D312
I(Page 18)
C(Page 15)
H(Page 17)
TL-CH
TR-CH
RL-CH
RR-CH
F(Page 17)
TROUT
6V.N 1
AMS
U14
HPRE101 (2/2)
(ERASE)
SWITCHING
R-CH
ISS SWITCHING
Q41
z
TIMER
ISS
2 1
STEREO MONO
BUFFER
Q14
TAPE PLAY/REC DETECT
SENSOR
REC AMP
Q25
MUTING
Q26
TAPE TYPE
SELECT SWITCH
Q45
G(Page 18)
99
BIAS OSC
Q31
ALC
IN1
OUT1
ALC CONST
IN1
NF1
6-2. BLOCK DIAGRAM –TAPE DECK Section –

HCD-EP50
1717
•SIGNAL PATH
: RECORD
: TAPE PLAY
: CD PLAY
: TUNER
I2CDATA
INPINENA
SYSTEM CONTROLLER
IC301 (2/3)
EEPROM
IC302
CDDATA
CDCLK
CDRESET
L3
L4
F
(Page 16) RL-CH
TL-CH
RR-CH
TR-CH
DI CE
X2
X1
X301
4.194304MHz
7
3
I2CCLK 5
8
CD DOOR SW 19
45
MUTE 49
15
CL
14
LT4
516
12
3
42
16
43
CE
GENERALDOUT
GENERALCLK
47
1
2
GENERALDIN
100
PLLENA
48
SDA
5
SCL
6
10
9
L2
L1
LTOUT 2
11
B
(Page 15)
L
R
1
LVROUTLVRIN
30
RVROUT R-CH
R-CH
R-CH
CD-L-IN
CD-R-IN
CD BLOCK
INPUT SELECT SWITCH,
ELECTRICAL VOLUME
U6
R-CH
LINE AMP
U3
SOUND
CONTROL
CIRCUIT
R-CH
R-CH
MEGA BASS
CONTROL SWITCH
Q13
R-CH
PHONES
CN17
CD DO
CD CLK
CD \RESET
+
+
–
–
INPUT SELECT
SWITCH
SELECT SWITCH
SWITCH
LTCOM
4
LT3
6
LT2
7
LT1
8
+9V
R-CH
R-CH
H
(Page 16)
E
(Page 15)
TU-R
TU-L
CLOCK
DA IN
DA IN
CLOCK
DA OUT
STEREO
4
STEREO
TUNED
34
STATION
PLL CE
R-CH
D23
D17
D20
JK401
ZPUSH
OPEN/CLOSE
SW300
HEADPHONE
AMP
U9
MUTING
Q7
MUTING
Q21
SPEAKER
IMPEDANCE
USE 8Ω
POWER AMP
U11
6-3. BLOCK DIAGRAM – MAIN Section –

HCD-EP50
1818
SYSTEM CONTROLLER,
LIQUID CRYSTAL DISPLAY DRIVER
IC301 (3/3)
POWER ON/OFF
RELAY DRIVE
Q605, 606
POWER
TRANSFORMER
(MAIN)
T601
LINE
FILTER
L601
AC IN
POWER
TRANSFORMER
(SUB)
T602
RE601
B+ AMP
POWER AMP (U11) B+
D16
D8
D18
D19
CD-EN
TU-EN
D318
D35
RESET 12
PWRFAIL 14
D701 –709
(LCD BACK LIGHT)
REMOTE CONTROL
RECEIVER
X302
13 REMOTE
FM ON/OFF
CD-EN, TU-EN
ROTARY
ENCODER
X303
ENCODERA
25
ENCODERB
26
SEG30 (SEL6)
90
SEG31 (SEL7)
91
SEG37
97
SEG32
92
SEG29
89
SEG28
88
28 –32
COM0 –COM3 KEY1 –KEY5
51 –54
SEG0 –SEG27
60 –87
SW301 –317
X303
VOLUME
LIQUID CRYSTAL
DISPLAY
CN301
RECT
D606, 608
RECT
D612, 613,
D616, 618
RECT
D602, 604
+8V
REGULATOR
Q9, 12
8V (CD)
CD BLOCK B+
9V
TAPE DECK SECTION,
LA1837 (U1) B+
M12V
CAPSTAN/REEL MOTOR B+
VT12V
FM CIRCUIT B+
5V (CPU)
SYSTEM CONTROLLER (IC301),
EEPROM (IC302),
94HC4094 (U15) B+
REGULATOR
CONTROL SWITCH
Q15
+12V
REGULATOR
Q47
+5V
REGULATOR
U8
+12V
REGULATOR
U7
+9V
REGULATOR
U10
FM/AM PLL (U2) B+
RDS DECODER
(IC305) B+
RESET SIGNAL
GENERATOR
IC304
RDSCLK 15
RDSDATA 35
POWER
RDATA
RCLK
50
RESET
SWITCH
Q306
D303 D302 D301 D304
SW1
D307
A
(Page 15)
I
(Page 16)
G
(Page 16)
D
(Page 15)
-1-2
AM FREQ
STEP
9kHz 10kHz
SWITCHING
BUFFER
Q302
SWITCHING
Q301
B+ SWITCH
Q303
B+ SWITCH
Q4, 10
B+ SWITCH
Q4, 10
B+ SWITCH
Q19, 20
( AEP, UK)
( AEP, UK)
EXCEPT AEP,
UK, Chinese
EXCEPT AEP,
UK, Chinese
AEP, UK,
Chinese
6-4. BLOCK DIAGRAM – DISPLAY/POWER SUPPLY Section –
Ver 1.1

HCD-EP50
1919
L901
FM FREQUENCY
COVERAGE
L902, TC901
FM TRACKING
3.4
0.8
3.2 3.2 3.2 3.2 3.2
0.8 3.2 3.2
(EXCEPT AEP, UK, CH)
0.047 0.047 0.047
0.047
0.001
1SS133T
FM OSC
L902
FM RF
0.047 0.047
0.001
B. P. F.
12 3
0.001
FM OSC
BUFFER
0.001
0.047 0.047
0.047
0.047
0.047
1SS133T
0.047
15
4
MAIN
BOARD
(1/3)
G
i
i
i
i
GND
i
OSCO
i
VCC
GND
GND
IF OUTPUT
i
RF INPUT
i
VT
IC901
FM RF AMP/MIX/OSC
AM RF
IN
FM RF
OUT
AM/FM
SW
FM OSC
AM OSC
AFC
DET
OUT
QUAD
FM RF IN
RF GND MIX OUT AGC VCC FM IF IN AM IF IN GND
(INCLUDED IN MAIN BOARD)
3
IC B/D
6-5. NOTE FOR PRINTED WIRING BOARDS AND SCHEMATIC DIAGRAMS 6-6. SCHEMATIC DIAGRAM – FMTUNER Section – • See page 28 for IC Block Diagram.
Note on Printed Wiring Board:
•W: indicates side identified with part number.
•: Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
Note on Schematic Diagram:
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in Ωand 1/4W or less unless otherwise
specified.
•f: internal component.
•C: panel designation.
•A: B+ Line.
•H: adjustment for repair.
• Voltages and waveforms are dc with respect to ground
under no-signal (detuned) conditions.
no mark : FM
( ) : AM
{} : CD PLAY
[ ] :TAPE PLAY
< > : RECORD (ISS 1)
〈〈 〉〉 : RECORD (ISS 2)
∗: Impossible to measure
• Voltages are taken with aVOM (Input impedance 10 MΩ).
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.
• Circled numbers refer to waveforms.
• Signal path.
F: FM
f: AM
E:TAPE PLAY
a: RECORD
J: CD PLAY
• Abbreviation
AR : Argentina model
CH : Chinese model
CND : Canadian model
HK : Hong Kong model
MX : Mexican model
SP : Singapore model
Note:
The components identi-
fied by mark 0or dotted
linewithmark 0arecriti-
cal for safety.
Replace only with part
number specified.
Note:
Lescomposantsidentifiéspar
une marque 0sont critiques
pour la sécurité.
Ne les remplacer que par une
pièce portant le numéro
spécifié.
(Page
20)
Ver 1.1

HCD-EP50
2020
IC B/D
IC B/D
IC B/D
MAIN BOARD
(2/3)
2
MAIN BOARD
(2/3)
1
NC
MAIN BOARD
(2/3)
3
DSIPLAY
BOARD
A
DSIPLAY
BOARD
B
MAIN BOARD
(3/3)
4
DSIPLAY
BOARD
C
MAIN BOARD
(3/3)
6
MAIN BOARD
(2/3)
5
1
(EXCEPT AEP, UK, CH)
(AEP, UK, CH)
INCLUDED IN
MAIN BOARD
G
T6, TC1
AM TRACKING
T8
AM FREQUENCY
COVERRAGE
AM IF
12.5
11.3
(0)
12 (0.1)
12.2 (0.1)
0.1 (0.7)
0
5.4
1.5
11
0
0
2.6 (0)
8.6 (0)
3.4 (0)
3.6
7.7 (8)
3.6
3.6
5.8
5.8
7.7 (8) 7.7 (8)
1.2
0.5 (0)
0
0
6.6 (3.8)
3.7
4.3
4.3 4.3
4.3
3.3 3.3
2.9
3.9
0 (0.6)
0 (0.6)
2.8 (3.6)
2.8 (3.6)
3.7
3.7
2.1
6.7 (0.1)
0.1
(0.7)
6.7
0
0
0 (2.3)
2.3 (0)
4.9
0.9
0.9
1.3
2.4 2.3
0
0
4.9
4.9
0.1 (4)
0
2.8
0.9
1.6
4.9
4.1
4.9
0.7
0.1
0
0
0
0
0
0
0
0
4.4
4.4
4.4
4.5
4.5
8.1
4.5
0
5
0 {0} [0] <4.6>
0 {0} [4.6] <0> 0 {4.6} [0] <0>
4.6 {0} [0] <0>
5
5 5 5
5 5 5
5
5
5
5
5 5 5
5
5
4.6 {0} [0] <0>
0 {4.6} [0] <0>
0 {0} [4.6] <0>
0 {0} [0] <4.6>
7.7
5
0
(EXCEPT AEP, UK, CH)
(EXCEPT AEP, UK, CH)
(AEP, UK, CH)
AM ANT
CN12
FM ANT
75Ω
COAXIAL
CN13
i
CLOCK
i
DA_IN
i
RR-CH
i
RL-CH
i
TR-CH
i
TL-CH
i
RF INPUT
i
GND
i
GND
i
GND
i
VT
i
VCC
i
IF OUTPUT
i
OSCO
*CD
BLOCK
*SUPPLIED AS THE
ASSEMBLED BLOCK
CN3
9P
Q4, 10
B+ SWITCH
AM RF
U1
FM/AM IF AMP,
AM RF AMP/MIX/OSC,
FM/AM DET, MPX
FM IF AMP
U1
LA1837
OSC BUFF
FM SD. ADJ
AM-OSC
REG
AM-
RF-IN
AM-AGC
AGC
AM-DET
OUT
FM-DET
OUT
MPX-IN
OUT L
OUT R
AMP-
IN L
AMP-
IN R
AMP-
OUT L
AMP-
OUT R
FM-IN AM-MIX FM-IF AM-IF GND TUNED STEREO VCC FM DET AM. SD FM. SD AM. SD ADJ IF-BUFF MUTE AM/FM VCO-STOP
Q3
FM/AM BAND
SELECT SWITCH
Q17
STEREO/MONO
SWITCHING
BUFFER
Q1, 11
B+ SWITCH
IFIN
IO2
AMIN
FMIN
VDD
PD
AIN
AOUT
VSS
XOUT XIN
CE
DI
CL
DO
BO1
BO2
BO3
BO4
IO1
U2
FM/AM PLL
U6
INPUT SELECT SWITCH,
ELECTRICAL VOLUME
U3
LINE AMP
VCC
GND
Q13, 16
MEGA BASS CONTROL SWITCH
Q6, 7
MUTING
CE
VSS
VREF
R1 R2 R3 R4
RT1 RT2 RT3 RT4
RTCOM
RTOUT
RVRIN
RVROUTLVROUT
LVRIN LTOUT LTCOM LT4 LT3 LT2 LT1 L4 L3 L2 L1 VDD CL DI
i
TIMER
i
TU-EN
i
STR
i
POWER-FAIL
i
POWER-LINE
i
REC. LED+
i
BEAT
i
MUTE-LINE
i
R-CH
i
L-CH
CN4
3P
RDS_DA
CN11
7P
DA
CLK
RESET
RESET
DA
CLK
MAIN BOARD (1/3)
TP
(AM VT)
CN5
11P
0.1
0.1
0.001
0.1
0.001
0.001
0.001
50V
50V
0.022
50V
50V
50V
50V
50V
50V
50V
50V
50V
50V
50V
50V
0.033
0.047
0.0056
0.022
0.047
0.1
50V
0.1 0.1
0.1
0.001
0.001
0.1 0.1 0.1
50V
0.047
0.0056
0.022
0.0047
0.033
50V
50V
0.1
50V
0.047
50V
0.047
0.047
50V
50V
50V
50V
0.0068
0.0047
0.0047
0.0047
0.022
50V
L. P. F.
50V
50V
0.033
16V
0.0068
L. P. F.
0.0047
0.022
0.047
50V
0.047
50V
0.001
0.047
0.047
0.01
FRONT-END
0.001
R239
3.3M
1/2W
0.047
16V
0.047
0.047
0.001
TP
(FM VT)
(AEP, UK, CH)
1SS133T
1SS133T
1SS133T
1SS133T
1SS133T
16V
0.47 50V
0.47 50V
1SS133T
1SS133T
6-7. SCHEMATIC DIAGRAM – MAIN Board (1/3) – • See page 28 forWaveform. •See page 28 for IC Block Diagrams.
(Page 19)
(Page 21)
(Page 21)
(Page 21)
(Page 25)
(Page
25)
(Page 22)
(Page
25)
(Page 21)
(Page 22)
Ver 1.1