DOWNLOAD Sony CMT-EH45DAB / HCD-EH45DAB Service Manual ↓ Size: 3.29 MB | Pages: 38 in PDF or view online for FREE

Model
CMT-EH45DAB HCD-EH45DAB
Pages
38
Size
3.29 MB
Type
PDF
Document
Service Manual
Brand
Device
Audio
File
cmt-eh45dab-hcd-eh45dab.pdf
Date

Sony CMT-EH45DAB / HCD-EH45DAB Service Manual ▷ View online

HCD-EH45DAB
10
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, appiy 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
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 1dB 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.
HCD-EH45DAB
11
Adjustment Location: Record/Playback/Erase Head
Note:  Remove the cassette lid before this adjustment.
 
Refer to “DISASSEMBLY” (page 6)
TUNER SECTION     
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 adjust-
ment.
2.  Use YEDS-18 disc (3-702-101-01) unless otherwise indicat-
ed.
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 fol-
lowing checks.
5.  Check the focus bias check when optical pick-up block is re-
placed.
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
HCD-EH45DAB
12
SECTION  7
DIAGRAMS
For Schematic Diagrams.
Note:
•  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 Ω and 1/4 W or less unless otherwise 
specifi ed.
•      f : 
internal 
component.
•  C : panel designation.
THIS  NOTE  IS  COMMON  FOR  PRINTED  WIRING  BOARDS  AND  SCHEMATIC DIAGRAMS.
(In addition to this, the necessary note is printed in each block.)
•  A : B+ Line.
•  Voltages and waveforms are dc with respect to ground 
under no-signal (detuned) conditions.
  – CD Board –
  no mark : CD PLAY
  – Other Section –
  no mark : TUNER
  (         ) : CD PLAY
  [         ] : TAPE PLAY
  ‹‹      ›› : REC
•  Voltages are taken with VOM (Input impedance 10 M
Ω).
  Voltage variations may be noted due to normal production 
tolerances.
•  Waveforms are taken with a oscilloscope.
  Voltage variations may be noted due to normal production 
tolerances.
•  Circled numbers refer to waveforms.
• Signal path.
  F : 
TUNER
  J 
: CD PLAY
  E : 
TAPE 
PLAY
 
 : 
REC
  f 
:  AUDIO IN
For Printed Wiring Boards.
Note:
•  X : Parts extracted from the component side.
•  Y : parts extracted from the conductor side.
•   W  : indicates side identifi ed with part number.
•      f  : internal component.
• 
 : Pattern from the side which enables seeing.
  (The other layers' patterns are not indicated.)
•  Indication of transistor.
 
C
B
These are omitted.
E
Q
 
B
These are omitted.
C E
Q
Caution:
Pattern face side:
(Conductor Side)
Parts face side: 
(Component Side)
Parts on the pattern face side seen from 
the pattern face are indicated.
Parts on the parts face side seen from 
the parts face are indicated.
Note: The components identifi ed by mark 0 or dotted 
line with mark 0 are critical for safety. 
 
Replace only with part number specifi ed.
HCD-EH45DAB
HCD-EH45DAB
13
13
•  Circuit Board Location
MAIN board
PANEL board
CD board
PT-AC board
MODULE
(DAB tuner)
• Waveforms
– CD Board –
IC101 JB (RFi)
(CD play mode)
200 mV/DIV, 500 ns/DIV
0.5 to 1.3 Vp-p
IC101 XG (XO)
(CD play mode)
1 V/DIV, 20 ns/DIV
59.1 ns
3.3 Vp-p
RB
Q507 (Base)
2 V/DIV, 5 
μs/DIV
14.6
μs
4.4 Vp-p
RT
Q507 (Collector)
5 V/DIV, 5 
μs/DIV
14.6
μs
10 Vp-p
XT
IC701 PT (X1)
1 V/DIV, 50 ns/DIV
181 ns
2.7 Vp-p
XB
IC701 RG (X3)
1 V/DIV, 10 
μs/DIV
30.5
μs
2.8 Vp-p
– MAIN Board –
– PANEL Board –
Page of 38
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