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Model
CMT-EH15 HCD-EH15
Pages
41
Size
3.57 MB
Type
PDF
Document
Service Manual
Brand
Device
Audio
File
cmt-eh15-hcd-eh15.pdf
Date

Sony CMT-EH15 / HCD-EH15 Service Manual ▷ View online

HCD-EH15
9
SECTION  4
TEST  MODE
COLD  RESET
The cold reset clears all data including preset data stored in the 
memory to initial conditions. Execute this mode when returning 
the set to the customer.
Procedure:
1.  Press three buttons of [
x
], [
l
 
m
 – TUNING] and [
?/1
simultaneously.
2.  When “RESET” appears, the set enters standby status.
PANEL  TEST
Procedure:
1.  Press the [
?/1
] button to turn the power on.
2.  Press three buttons of [FUNCTION], [TUNER/BAND], and 
[
?/1
] simultaneously.
3.  When the panel test is activated, [STANDBY] LED and seg-
ments on the liquid crystal display are all turned on.
4. Press 
the 
[CD 
u
] button, date and version are displayed. For 
example, “1115V002”.
5.  Press the [TUNER/BAND] button, model name and destination 
are displayed. For example, “EH15ASIA”.
6.  To release from this mode, press three buttons of [FUNCTION], 
[TUNER/BAND], and [
?/1
] simultaneously.
TUNER  STEP  CHANGE 
(Except AEP, Russian and UK models)
The AM tuning interval can be changed over 9 kHz or 10 kHz.
Procedure:
1.  Press the [
?/1
] button to turn the power on.
2.  Press the [TUNER/BAND] button to select TUNER (AM) 
function.
3.  Press the [
?/1
] button again to turn the power off (standby).
4.  After pressing the [DISPLAY] button on the remote command-
er, while pressing the [TUNING + 
M
 
L
] button, press the 
[
?/1
] button.
5.  It turns power on and display “9K STEP” or “10K STEP”, and 
thus the tuning interval is changed over.
CD  SERVICE  MODE
This mode can move the SLED of the optical pick-up, and also can 
turn the optical pick-up laser power on and off.
Procedure:
1.  Press the [
?/1
] button to turn the power on.
2.  Press the [FUNCTION] button to select CD function.
3.  Press three buttons of [
l
 
m
 – TUNING], [FUNCTION], 
and [
?/1
] simultaneously.
4.  It enters the CD service mode and displays “SERVICE”.
5.  To release from this mode, press three buttons of [
l
 
m
 
– TUNING], [FUNCTION]  and [
?/1
] simultaneously.
Key Operation:
[TUNING + 
M
 
L
], [
l
 
m
 – TUNING]: 
 
Use these keys to move the SLED. When [TUNING 
M
 
L
] is pressed in this mode, the SLED moves 
to outer circumference and the message “SLED 
OUT” is displayed.
 When 
[
l
 
m
 – TUNING] is pressed in this 
mode, the SLED moves to inner circumference and 
the message “SLED IN” is displayed. 
[FUNCTION]: 
 
Use this key to turn the optical pick-up laser power 
on and off. When the laser power is turned on, the 
message “LD ON” is displayed. When the laser 
power is turned off, the message “LD OFF” is dis-
played. 
CD  ERROR  CODE
The past errors of the optical pick-up system (= optical unit + CD 
board) are displayed as the BD Errors as shown below. 
Procedure:
1.   Press the [
?/1
] button to turn the power on.
2.   Press the [FUNCTION] button to select CD function.
3.  Press three buttons of [
l
 
m
 – TUNING], [DSGX] and 
[
?/1
] simultaneously.
4.  Then, the BD error code is displayed as “D0xxxxxx” (x means 
hexadecimal number) on the liquid crystal display as shown 
below. 
5.  Every pressing of the [TUNING + 
M
 
L
] button in this 
mode increments the number after “D” starting from “D0” up 
to “D4”, and then returns to “D0”. Every pressing of the [
l
 
m
 – TUNING] button in this mode decrements the number 
after “D”. The smaller the error code number is, the newer the 
error content is. 
6.  To release from this mode, press the [
?/1
] button to turn the 
power off.
Contents of “BD Errors”  
Error display example
 
D  0  01 06 01
 
 
1  2  3  4
1  It indicates the error history number
 
0 to 4: The error code number 0 indicates the newest error.
2  It indicates the error content
01: The focus servo cannot lock-in. 
02: GFS is no good (NG).
03: The startup time exceeds the specifi ed period of time (time 
over)
04:  The focus servo is unlocked continuously. 
05:  Q code cannot be obtained within the specifi ed period of 
time.
06: The tracking servo cannot lock-in.
07: Blank disc
 
3  It indicates the on-going processing of optical pick-up system 
(= optical unit + CD board) when the trouble has occurred.
01:   The CD SHIP mode processing is in progress.
02:   The POWER OFF processing is in progress.
03:  The POWER ON processing is in progress.
04:   The INITIALIZE processing is in progress.
05:   The optical pick-up system (= optical unit + CD board) is 
in the stop state. 
06:   The STOP operation is in progress.
07:   The startup processing is in progress.
08:   The TOC read-in processing is in progress.
09:   The SEARCH operation is in progress.
0A:  The PLAY operation is in progress.
0B:  The PAUSE operation is in progress.
0C:  The PLAY – MANUAL SEARCH operation is in prog-
ress.
0D:  The PAUSE – MANUAL SEARCH operation is in prog-
ress.
4  It indicates the operation that is being processed when the trou-
ble has occurred.
 
It indicates the step number of each processing specifi ed by 
3. 
Because the numbers of steps are different in each processing, 
this number is different in each processing.
Ver. 1.2
HCD-EH15
10
SECTION  6
ELECTRICAL  ADJUSTMENTS
DECK SECTION      0 dB = 0.775 V
1.  Demagnetize the record/playback head with a head
 demagnetizer. 
2.  Do not use a magnetized screwdriver for the adjustments.
TEST  TAPE
Tape
Signal
Used for
P-4-A063
6.3 kHz, –10 dB
Azimuth Adjustment
RECORD/PLAYBACK  HEAD  AZIMUTH  ADJUSTMENT
Procedure:
1. Mode: 
Playback
set
MAIN board
PHONES jack
(J102)
+
level meter
test tape
P-4-A063
(6.3 kHz, –10 dB)
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 1 dB of peak.
Screw
position
L-CH
peak
within
1 dB
Output
level
L-CH
peak
R-CH
peak
within
1 dB
Screw
position
R-CH
peak
3. Mode: 
Playback
set
test tape
P-4-A063
(6.3 kHz, –10 dB)
oscilloscope
V
H
waveform of oscilloscope
in phase 45
°
90
° 135° 180°
good
wrong
MAIN board
PHONES jack
(J102)
4.  After the adjustments, apply suitable locking compound to the 
pats adjusted.
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 demag-
netizer. (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
FWD
CQ-102AS
2.0 – 8.0 mN • m
(20 – 80 g • cm)
(0.28 – 1.12 oz • inch)
FWD 
Back Tension
CQ-102C
0.15 – 0.6 mN • m
(1.5 – 6.0 g • cm)
(0.021 – 0.083 oz • inch)
FF
CQ-201AS
5.0 – 17.7 mN • m
(50 – 177 g • cm)
(0.7 – 2.48 oz • inch)
REW
CQ-201B
5.0 – 17.7 mN • m
(50 – 177 g • cm)
(0.7 – 2.48 oz • inch)
TAPE  TENSION  MEASUREMENT
Mode
Torque meter
Meter reading
FWD
CQ-403A
more than 80 g
(more than 2.82 oz)
SECTION  5
MECHANICAL  ADJUSTMENTS
HCD-EH15
11
Adjustment Location: Record/Playback/Erase Head
Note:  Remove the cassette lid before this adjustment.
 
Refer to “DISASSEMBLY” (page 6)
TUNER SECTION      0 dB=1 μV
[AM]
Setting:
Function: TUNER
Band: AM
AM RF signal 
generator
30% amplitude 
modulation by 
400 Hz signal
60 cm
set
loop antenna A
loop antenna B
[FM]
Setting:
Function: TUNER
Band: FM
FM RF signal
generator
1 kHz frequency
deviation by FM 75 kHz
signal
Output level: 
as low as possible
+
level meter
MAIN board
JW148
(GND)
MAIN board
JW403
(TUNER OUT L-ch)
set
MAIN board
CNP802 pin 
MAIN board
CNP802 pin 
digital voltmeter
JW821 (VT)
JW805 (GND)
10 k
Ω
MAIN board
•  Repeat the procedures in each adjustment several times, and 
the  tracking adjustments should be fi nally done by the trimmer 
capacitors.
•  Remove FM antenna in FM adjustment.
( ): AEP, Russian and UK models
AM  VT  VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L852
530 (531) kHz
1.5 ± 0.1 V
Confi rmation
1710 (1602) kHz
8.0 (7.2) ± 0.5 V
( ): AEP, Russian and UK models
AM  TRACKING  ADJUSTMENT
Adjust for a maximum reading on level meter
L851
530 (531) kHz
FM  VT  VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L805
87.5 MHz
1.75 ± 0.1 V
Confi rmation
108 MHz
6.2 ± 0.5 V
FM  TRACKING  ADJUSTMENT
Adjust for a maximum reading on level meter
L804
98 MHz
FM  DETECTOR  ADJUSTMENT
Setting:
Function: TUNER
BAND button: FM
set
MAIN board
JW403
(TUNER OUT L-ch)
MAIN board
JW148 (GND)
Carrier frequency : 98 MHz
Modulation
: deviation by
FM 75 kHZ
Output level
: 60 dB
FM RF Signal 
generator
1.  Tune the set to 98 MHz.
2.  Adjust L806 so that modulation distortion may become the 
best in the vicinity of the maximum value where the tuner out 
level becomes 
15 dBs or more.
Ver. 1.2
HCD-EH15
12
Adjustment Location:
L851
AM Tracking
Adjustment
L805
FM VT
Voltage
Adjustment
L804
FM Tracking
Adjustment
L806
FM Detector
Adjustment
L852
AM VT
Voltage
Adjustment
– MAIN Board (Component Side) –
JW403
(TUNER OUT L-ch)
JW402
(TUNER OUT R-ch)
JW148
(GND)
JW821
(VT)
CNP802
JW805
(GND)
– MAIN Board (Conductor Side) –
3
1
FM  TUNE  LEVEL  CHECK
signal
generator
set
Procedure:
1.  Turn on the set.
2.  Input the following signal from signal generator to FM antenna 
input directly.
Carrier frequency : A = 87.5 MHz, B = 98 MHz, C = 108 MHz
Deviation 
: 75 kHz
Modulation 
: 1 kHz
ANT input 
: 35 dBu (EMF)
Note:  Use 75 ohm coaxial cable to connect signal generator and the set. 
You cannot use video cable for checking.
 
Use signal generator whose output impedance is 75 ohm. 
3.  Set to FM tuner function and tune A, B and C signals.
4. Confi rm “TUNED” is lit on the display for A, B and C sig-
nals.
When the selected station signal is received in good condition, 
“TUNED” is displayed.
CD  SECTION
Note:
1.  CD Block is basically constructed to operate without adjustment.
2.  Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3.  Use an oscilloscope with more than 10 M
Ω impedance.
4.  Clean the object lens by an applicator with neutral detergent when the 
signal level is low than specifi ed value with the following checks.
5.  Check the focus bias check when optical pick-up block is replaced.
FOCUS  BIAS  CHECK
+
CD board
TP122 (RFEQO)
TP124 (VC)
oscilloscope
(DC range)
Procedure:
1.  Connect oscilloscope to TP122 (RFEQO) and TP124 (VC) on 
the CD board.
2.  Press the [
?
/
1
] button to turn the power on.
3.  Set the disc (YEDS-18) and press the [CD 
u
] button to play-
back.
4. Confi rm that oscilloscope waveform is as shown in the fi gure 
below. (eye pattern)
 
A good eye pattern means that the diamond shape (
◊) in the 
center of the waveform can be clearly distinguished. 
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
1.2 ± 0.3 Vp-p
Checking Location:
TP124
(VC)
– CD Board (Conductor Side) –
TP122
(RFEQO)
IC101
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