Sony CFD-44 Service Manual ▷ View online
– 9 –
SECTION 4
ADJUSTMENTS
4-2. ELECTRICAL ADJUSTMENTS
TAPE RECORDER SECTION
1. The adjustments should be performed in the publication. (Be sure
make playback adjustment at first.)
2. The adjustment and measurement should be performed for both
L-CH and R-CH.
r
Switch position
MEGA BASS : OFF
TONE
TONE
: mechanical center.
VOLUME
: as required.
Standard Output Level
Output terminal
HP OUT
load impedance
32Ω
output signal level
0.25V ( – 10 dB)
Test Tape
Type
Signal
Used for
WS-48A
3kHz, 0dB
Tape Speed Adjustment
P-4-A063
6.3kHz, –10dB
Head Azimuth Adjustment
0dB=0.775V
Tape Speed Adjustment
Procedure :
Procedure :
Mode : Playback
set
test tape
WS-48A
(3kHz, 0dB)
WS-48A
(3kHz, 0dB)
32
Ω
speed checker
LFM-30 or
digital frequency
counter
LFM-30 or
digital frequency
counter
2
jack (J301)
– +
Adjustment Value :
Speed checker
Digital frequency counter
±
2%
2,940 – 3,060Hz
Frequency difference between the beginning and the end of the tape
should be within 1.5% (45Hz).
Adjustment Location :
tape speed adjustment
control inside moter
control inside moter
4-1. MECHANICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab :
record/playback head
pinch roller
erase head
rubber belts
capstan
2. Demagnetize the record/playback head with a head demagnetizer.
(Do not bring the head demagnetizer 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
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
Torque Measurement
Torque
Torque Meter
Meter Reading
Forward
CQ-102C
30 – 70 g • cm
(0.42 - 0.97 oz• inch)
Forward
back tension
back tension
CQ-102C
1.0 – 6.0 g • cm
(0014 - 0.083 oz• inch)
Fast Forward
CQ-201B
more than 60g • cm
(more than 0.84oz• inch)
Rewind
CQ-201B
more than 60g • cm
(more than 0.84oz• inch)
Tape Tension Measurement
Tension Meter
Meter Reading
CQ-403A
more than 90g
(more than 3.18 oz)
– 10 –
Record/Playback Head Azimuth Adjustment
Procedure :
1. Mode : playback
Procedure :
1. Mode : playback
test tape
P-4-A063
(6.3kHz, - 10dB)
P-4-A063
(6.3kHz, - 10dB)
set
32
Ω
2
jack (J301)
level meter
L-CH
peak
peak
R-CH
peak
peak
L-CH
peak
peak
R-CH
peak
peak
Screw
position
position
output
level
level
within
2dB
within
2 dB
screw position
2. Turn the adjustment screw for the maximum output levels. If
these levels do not match, turn the adjustment screw until both
of output levels match together within 2dB.
these levels do not match, turn the adjustment screw until both
of output levels match together within 2dB.
3. Phase Check
Mode : playback
L-CH
set
32
Ω
R-CH
32
Ω
in phase 45
°
90
°
135
°
180
°
good
wrong
screen pattern
test tape
P-4-A063
(6.3kHz, - 10dB)
P-4-A063
(6.3kHz, - 10dB)
2
jack (J301)
OSCILLOSCOPE
Adjustment Location : – record / playback head –
adjustment screw
TUNER SECTION
AM Section
Function switch
: AM
Volume
: MAX
AM RF signal
generator
generator
30% amplitude modulation by 400Hz
signal.
Output level : as low as possible
signal.
Output level : as low as possible
Put the lead-wire
antenna close to
the set.
antenna close to
the set.
FM Section
Function switch
: FM
Volume
: MAX
FM RF signal
generator
generator
22.5kHz frequency deviation by
400Hz signal.
Output level : as low as possible
400Hz signal.
Output level : as low as possible
telescopic
antenna
terminal
antenna
terminal
0.01 F
µ
set
32
Ω
+
–
2
jack (J301)
level meter
+
–
VT
100
Ω
digital voltmeter
[MAIN BOARD] – Component side –
– 11 –
r
Repeat the procedures in each adjustment several times, and the
frequency coverage and tracking adjustments should be finally done
by the trimmer capacitors.
by the trimmer capacitors.
no mark : Common
( ) : US, Canadian model
< > : AEP, UK, Italian model
AM IF ADJUSTMENT
Adjust for a maximum reading on LEVEL METER.
CFT1
455kHz
AM FREQUENCY COVERAGE ADJUSTMENT
Adjust for following values on digital voltmeter.
Display indication
(530 kHz)
<531kHz>
(1,710 kHz)
<1,611kHz>
Display voltmeter reading
0.8
±
0.1V
5.5
±
0.6V
Adjustment part
L4
confirm
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on LEVEL METER.
L3
(620kHz) <621kHz>
CT2
(1,400kHz) <1,404kHz>
FM FREQUENCY COVERAGE ADJUSTMENT
Adjust for following values on digital voltmeter.
Display indication
108 MHz
87.5MHz
Display voltmeter reading
4.5
±
0.2V
2.0
±
0.2V
Adjustment part
L2
confirm
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on LEVEL METER.
L1
87.5MHz
CT1
108.0MHz
Adjustment Location : Main board (See page 14)
CD SECTION
Note on Adjustment
1.
Perform adjustment in test mode.
After adjustment, be sure to release test mode.
After adjustment, be sure to release test mode.
2.
Perform adjustments in the order given.
3.
Use the disc (YEDS-18. Part No. 3-7029-101-01) only when
so indicated.
so indicated.
How to put the Set into Test Mode
Turn the power on while pressing 3 buttons. (1 button, RADIO
button and STOP
button and STOP
p button.)
How to release Test Mode
Turn the power off.
Before adjustment
Put the set into test mode and perform the following checks.
Repair if there are any problems.
Repair if there are any problems.
r
Sled Motor Check
1. Press
+,=buttons and confirm that the Optical pick-up
moves smoothly from the innermost to outermost circumfer-
ence and back smoothly and with no catching or abnormal
noises.
ence and back smoothly and with no catching or abnormal
noises.
+
: Optical pick-up moves to the outer circumference
=
: Optical pick-up moves to the inner circumference
r
Focus Search Check
1. Press CD PLAY
· button. (Focus search operation is per-
formed continuously.)
2. Look at the Optical pick-up objective lens and confirm that it
moves up and down smoothly, with no catching or abnormal
noises.
noises.
3. Press STOP
p button.
Confirm that focus search operation stops. If it does not ,
press OFF button again longer.
Note :
When the malfunction is occurred by mis-passing other
keys, turn off the power and check again from making
the test mode.
the test mode.
E-F Balance Adjustment
This adjustment is to be done when the optical pick-up block is
replaced.
replaced.
Procedure :
1. Connect the oscilloscope between TP (TO) and TP (VC) on
CD main board.
2. Put the set into test mode.
3. Press the
3. Press the
+ and = buttons to move the optical pick-up to
the center.
4. Insert disc (YEDS-18) and press CD PLAY
· button.
5. Adjust RV703 so that the oscilloscope traveres waveform is
symmetrical, as shown in the figure below.
6. Release test mode after adjustment is completed.
A
OV
B
C
VOLT / DIV : 1V
TIME / DIV :1ms
TIME / DIV :1ms
A = B
C = 400mV
±
100mV
– 12 –
+
-
OSCILLOSCOPE
(DC range)
(DC range)
TP (TO)
TP (VC)
[CD MAIN BOARD] – Component side –
Adjustment Location : CD Main board (See page 14)
Focus Bias Adjustment
This adjustment is to be done when the optical pick-up block is re-
placed.
This adjustment is to be done when the optical pick-up block is re-
placed.
Adjustment procedure :
1.Connect oscilloscope to test point TP (VC) and TP (RF) on CD
MAIN BOARD.
2.Put the set into model.
3.Optical pic-up setting to the center by
3.Optical pic-up setting to the center by
+ or = button to
pushing.
4.Insert disc (YEDS-18) and press CD PLAY
· button.
5.Press CD PLAY
· button again.
6.Adjust RV701 so that the oscilloscope waveform is as shown in
the figure below (eye pattern).
A good eye pattern means that the diamond shape (
A good eye pattern means that the diamond shape (
◊
) in the
center of the waveform can be clearly distinguished.
7.Release test mode after adjustment is completed.
r
RF signal reference waveform (eye pattern)
1.1
±
0.2V
VOLT/DIV : 0.2V
TIME/DIV : 500ns
TIME/DIV : 500ns
When observing the eye pattern, set the oscilloscope for AC
range and raise vertical sensitivity.
range and raise vertical sensitivity.
+
-
OSCILLOSCOPE
(DC range)
(DC range)
TP (RF)
TP (VC)
[MAIN BOARD] – Component side –
Adjustment Location : CD Main board (See page 14)
Focus/Tracking Gain Adjustment
A frequency responce analyzer is necessary in order to perform this
adjustment exactly.
However, this gain has a margin, so even if it is slightly off, there is
no problem. Therefore, do not perform this adjustment.
Focus/tracking gain determines the pick-up follow-up (vertical and
horizontal) relative to mechanical noise and mechanical shock when
the 2-axis device operate.
However, as these reciprocate, the adjustment is at the point where
both are satisfied.
A frequency responce analyzer is necessary in order to perform this
adjustment exactly.
However, this gain has a margin, so even if it is slightly off, there is
no problem. Therefore, do not perform this adjustment.
Focus/tracking gain determines the pick-up follow-up (vertical and
horizontal) relative to mechanical noise and mechanical shock when
the 2-axis device operate.
However, as these reciprocate, the adjustment is at the point where
both are satisfied.
r
When gain is raised, the noise when the 2-axis device operates
increases.
increases.
r
When gain is lowered, mechanical shock and skipping occurs
more easily.
more easily.
r
When gain adjustment is off, the symptoms below appear.
r
The time until music starts becomes
longer for STOP
→
·
PLAY or
automatic selection.
(
(
=, + buttons pressed.)
(Normally takes about 2 seconds.)
r
Music does not start and disc
continues to rotate for STOP
→
·
PLAY or automatic selection.
(
=, + buttons pressed.)
r
Sound is interrupted during PLAY.
Or time counter display stops
progressing.
progressing.
r
More noise during 2-axis device
operation.
Symptoms
Gain
Focus
Tracking
low
low or high
–
low
–
low
high
high
The following is a simple adjustment method.
– Primary Adjustment –
Note :
Since exact adjustment cannot be performed, remember the
positions of the controls before performing the adjustment.If
the positions after the primary adjustment are only a little dif-
ferent, return the controls to the original position.
the positions after the primary adjustment are only a little dif-
ferent, return the controls to the original position.
Click on the first or last page to see other CFD-44 service manuals if exist.