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Model
HCD-VM330AV
Pages
85
Size
11.56 MB
Type
PDF
Document
Service Manual
Brand
Device
Audio
File
hcd-vm330av.pdf
Date

Sony HCD-VM330AV Service Manual ▷ View online

16
HCD-VM330AV
Tape Speed Check
DECK B
Mode: Playback
1. Insert the WS-48A into the deck B.
2. Press the nN button on the deck B.
3. Confirm that the frequency counter reads 3,000 
±
 60 Hz.
Sample value of Wow and Flutter: 0.3% or less W.RMS (JIS)
(WS-48A)
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. 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
set
test tape
P-4-A100
(10 kHz, – 10 dB)
R-CH
oscilloscope
L-CH
R-CH
V
H
waveform of oscilloscope
in phase 45
°
90
°
135
°
180
°
good
wrong
MAIN AMP board
FRONT SPEAKER terminal (J501)
L-CH
+
set
test tape
WS-48A 
(3 kHz, 0 dB)
MAIN AMP board
FRONT SPEAKER terminal (J501)
L-CH, R-CH
frequency counter
Record/Playback Head Azimuth Adjustment
Note:
 Perform this adjustments for both decks
Procedure:
1. Mode: Playback (FWD)
DECK A      DECK B
set
MAIN AMP board
FRONT SPEAKER terminal (J501)
L-CH, R-CH
+
level meter
test tape
P-4-A100
(10 kHz, – 10 dB)
Adjustment Location: Playback Head (Deck A).
Record/Playback/Erase Head (Deck B).
reverse
forward
17
HCD-VM330AV
CD SECTION
Note :
1. CD Block is basically designed to operate without adjustment.
Therefore, check each item in order given.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10M
 impedance.
4. Clean the object lens by an applicator with neutral detergent
when the signal level is low than specified value with the
following checks.
S-Curve Check
Procedure :
1. Connect an oscilloscope to TP (FEO) and TP (DVC).
2. Connect between TP (FEI) and TP (VC) by lead wire.
3. Turn Power switch on.
4. Load the disc (YEDS-18) and actuate the focus search. (In
consequence of open and close the disc tray, actuate the focus
search)
5. Confirm that the oscilloscope waveform (S-curve) is
symmetrical between A and B. And confirm peak to peak level
within 4 
±
1 Vp-p.
7. After check, remove the lead wire connected in step 2.
Note :
• Try to measure several times to make sure than the ratio
of A : B or B : A is more than 10 : 7.
• Take sweep time as long as possible and light up the
brightness to obtain best waveform.
RF Level Check
Procedure :
1. Connect an oscilloscope to TP (RFAC) and TP (DVC).
2. Turn Power switch on.
3. Load the disc (YEDS-18) and playback.
4. Confirm that the oscilloscope waveform is clear and check RF
signal level is correct or not.
5. Measure the RFDC in the same way.
BD board
Oscilloscope
TP(FEO)
TP(DVC)
symmetry
S-curve waveform
within 4 
±
1Vp-p
A
B
TP (RFAC) or TP(RFDC)
TP(DVC)
BD board
oscilloscope
Note:
Clear RF signal waveform means that the shape “
” can be
clearly distinguished at the center of the waveform.
RF signal waveform
E-F Balance (1 Track jump) Check
Procedure:
1.
Connect an oscilloscope to TP (TEO) and TP (DVC).
2.
Turn Power switch on.
3.
Load the disc (YEDS-18) and playback the number five track.
4.
Press the  X  button. (Becomes the 1track jump mode.)
5.
Confirm that the level B and A (DC voltage) on the oscilloscope
waveform.
1 track jump waveform
Specification level:      
x
 100=less than 
±
22%
6.
After check, remove the lead wire connected in step 1.
RF PLL Free-run Frequency Check
Procedure :
1.
Connect a frequency counter to TP (XPCK) and GND.
2.
Turn Power switch on.
3.
Load the disc (YEDS-18) and playback the number five track.
4.
Confirm that the reading on frequency counter is 4.3218MHz.
oscilloscope
BD board
TP (TEO)
TP (DVC)
+
A
B
+
frequency counter
BD board
TP (XPCK)
VOLT/DIV : 200mV
TIME/DIV : 500ns
level : 1.1 
±
 0.3Vp-p 
0V
Center of
waveform
B
Symmetry
A (DC voltage)
level=1.3 
±
0.6Vp-p
18
HCD-VM330AV
Checking Location :
[ BD BOARD ] — SIDE B —
TP (DVC)
TP (FEO)
TP (XPCK)
TP (TEO)
TP (RFDC)
TP (VC)
TP 
(RFAC)
IC103
IC101
TP (FEI)
R120
VIDEO SECTION
Video Frequency Adjustment
Connection:
Procedure:
1. Connect a frequency counter to TP (27MHz) and TP (GND).
2. Turn power switch on.
3. Turn the 
[FUNCTION]
 knob of amplifier unit (TA-SV7AV) to
set the CD function.
4. Adjust CT503 on the VMP board so that the frequency counter
reading 27.0 MHz 
±
 80 Hz at stop status.
Adjustment Location:
[VMP BOARD] (SIDE A)
J301
CN501
CN502
IC507
TP (GND)
TP (27MHz)
CT503
Video 
Frequency
Adjustment
VMP board
TP (27MHz)
TP (GND)
frequency counter
19
HCD-VM330AV
SENSOR SECTION
Disc Sensor Level Adjustment
Procedure:
1.
Connect an oscilloscope to TP (DISC SENSOR) and TP (GND)
on the MAIN board.
2.
Turn the power on.
3.
In the no disc status, adjust RV301 on the MAIN board so that
the waveform of oscilloscope becomes as below. And check
the peak to peak level is more than 4 Vp-p.
4.
Insert a disc into the disc slot No. 58.
5.
Check that the waveform of oscilloscope as below. And adjust
RV301 on the MAIN board so that the peak to peak level
becomes less than 0.5 Vp-p besides becomes as little as possible.
6.
Check that the waveform and peak to peak level satisfy
specification of step 4. If it is wrong, repeat from step 4 until
satisfy.
Adjustment Location:
Waveform when no disc
,
turn the RV301
NG
OK
more than 4 Vp-p
Waveform when disc in
less than 0.5 Vp-p
[MAIN BOARD] (CONDUCTOR SIDE)
RV301
Disc Sensor Level
Adjustment
TP (GND)
TP (DISC SENSOR)
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