HCD-GPZ6, HCD-GPZ7 (serv.man2) - Sony Audio Service Manual (repair manual). Page 17

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HCD-GPZ6/GPZ7
17
17
HCD-GPZ6/GPZ7
Checking Location:
+
BD board
TP (RFACI)
TP (VC)
oscilloscope
(DC range)
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
0.9 
±
 0.4 Vp-p
TP
(VC)
TP
(RFACI)
IC201
– BD Board (Conductor Side) –
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
 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.
5.
Check the focus bias check when optical pick-up block is replaced.
FOCUS  BIAS  CHECK
Procedure :
1. Connect oscilloscope to TP (RFACI) and TP (VC) on the BD
board.
2. Press the
I/
1 button to turn the power ON, and press
the Z (CD) button to open the CD disc tray.
3. Set disc (YEDS-18) on the tray and press the
CD
 u button
to playback.
4. Confirm that oscilloscope waveform is as shown in the figure
below. (eye pattern)
A good eye pattern means that the diamond shape (
) in the
center of the waveform can be clearly distinguished.
Adjustment Location: Record/Playback/Erase Head
adjustment
screw
cassette tape
5. ELECTRICAL  ADJUSTMENTS
Screw
position
L-CH
peak
within
1dB
Output
level
L-CH
peak
R-CH
peak
within
1dB
Screw
position
R-CH
peak
0 dB=0.775 V
DECK  SECTION
set
PANEL (2) board
PHONES jack
(J321)
+
level meter
test tape
P-4-A063
(6.3 kHz, 
10 dB)
1. Demagnetize the record/playback head with a head
demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
Test Tape
RECORD/PLAYBACK  HEAD  AZIMUTH  ADJUSTMENT
Procedure:
1. Insert the tast tape with cassette lid keep opened.
2. Mode:  Playback
3. 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.
4. Mode:  Playback
5. After the adjustments, apply suitable locking compound to
the pats adjusted.
Tape
Signal
Used for
P-4-A063
6.3 kHz,  –10 dB
Azimuth Adjustment
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
PANEL (2) board
PHONES jack
(J321)
4. MECHANICAL  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. (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
2.95 – 6.86 mN
m
FWD
CQ-102C
(30 – 70 g
cm)
(0.42 – 0.97 oz
inch)
FWD
0.15 – 5.39 mN
m
Back Tension
CQ-102C
(1.5 – 5.5 g
cm)
(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)
Tape Tension  Measurement
Mode
Tension Meter
Meter Reading
FWD
CQ-403A
more than 100 g
(more than 3.53 oz)
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