DOWNLOAD Sony CMT-EP404 / HCD-EP404 Service Manual ↓ Size: 2.32 MB | Pages: 41 in PDF or view online for FREE

Model
CMT-EP404 HCD-EP404
Pages
41
Size
2.32 MB
Type
PDF
Document
Service Manual
Brand
Device
Audio
File
cmt-ep404-hcd-ep404.pdf
Date

Sony CMT-EP404 / HCD-EP404 Service Manual ▷ View online

11
HCD-EP404
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.
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
Tape Tension  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
P-4-A100
10 kHz, –10 dB
Head Azimuth Adjustment
WS-48B
3 kHz, 0 dB
Tape Speed Adjustment
Record/Playback Head Azimuth Adjustment
Procedure:
1.
Mode: Playback
level meter
test tape 
P-4-A100
(10 kHz, –10 dB)
set
HEADPHONE board
PHONES jack (JK501)
32 
+
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-A100
(10 kHz, –10 dB)
L-CH
R-CH
HEADPHONE board
PHONES jack (JK501)
oscilloscope
V
H
+ +
screen pattern
in phase
good
wrong
45 
°
90 
°
135 
°
180 
°
32 
32 
set
12
HCD-EP404
Tape Speed Adjustment
Setting:
Function: TAPE
Procedure:
1.
Playback WS-48B (tape center).
2.
Adjsut the volume in CAPSTAN/REEL motor 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 counter
test tape 
WS-48B
(3 kHz, 0 dB)
set
HEADPHONE board
PHONES jack (JK501)
+
32 
CAPSTAN/REEL
motor
Tape Speed
Adjustment
Adjustment Location: Record/Playback Head.
Note: Refer to “3-8. Cassette Lid” (see page 10)
adjustment screw
13
HCD-EP404
TUNER  SECTION
0 dB=1 
µ
V
[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 
HEADPHONE board
PHONES jack (JK501)
FM RF signal
generator
22.5 kHz frequency
deviation by 400 Hz
signal
Output level: as low as possible
+
level meter
set
32 
0.01 
µ
F
MAIN board
FM ANT
HEADPHONE board
PHONES jack (JK501)
digital voltmeter
100 k
MAIN board
TP (FM VT)
TP (AM VT)
AM  FREQUENCY  COVERAGE  ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
Confirmation
531 kHz
1.5 
±
 0.2 V
T101
1,602 kHz
7.3 
±
 0.3 V
AM  TRACKING  ADJUSTMENT
Adjust for a maximum reading on level meter
L110
603 kHz
TC102
1,404 kHz
FM  FREQUENCY  COVERAGE  ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
L103
87.5 MHz
2.1 
±
 0.2 V
Confirmation
108 MHz
7.0 
±
 0.4 V
FM TRACKING  ADJUSTMENT
Adjust for a maximum reading on level meter
L102
89.9 MHz
TC101
105.9 MHz
Adjustment Location: MAIN board (See page 14)
14
HCD-EP404
Adjustment Location and Connecting Points
– MAIN BOARD (Component Side) –
L104    
AM Tracking
TC102   Adjustment
TC102 
FM Tracking
L102      Adjustment
L103 FM Frequency
Coverage Adjustment
T101 AM Frequency
Coverage Adjustment
IC101
– MAIN BOARD (Conductor Side) –
TP(AM VT)
TP
(FM VT)
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