Sony HCD-GNX700 / HCD-GNX800 / MHC-GNX700 / MHC-GNX800 Service Manual ▷ View online
21
HCD-GNX700/GNX800
SECTION 5
MECHANICAL ADJUSTMENTS
SECTION 6
ELECTRICAL ADJUSTMENTS
Precaution
1. Clean the following parts with a denatured alcohol-moistened
swab:
record/playback heads pinch rollers
erase head
record/playback heads pinch rollers
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
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
2.9 mN • m to 6.9 mN • m
FWD
CQ-102C
30 to 70 g • cm
(0.42 – 0.97 oz • inch)
FWD
0.15 mN • m to 0.59 mN • m
back tension
CQ-102C
1.6 to 6 g • cm
(0.022 – 0.08 oz • inch)
4.8 mN • m to 16.7 mN • m
FF/REW
CQ-201B
49 to 170 g • cm
(0.69 – 2.36 oz • inch)
Mode
Torque meter
Meter reading
0 dB=0.775 V
DECK SECTION
1. Demagnetize the record/playback head with a head
demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
3. After the adjustments, apply suitable locking compound to the
3. After the adjustments, apply suitable locking compound to the
parts adjust.
4. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
5. The adjustments should be performed in the order given in
this service manual. (As a general rule, playback circuit
adjustment should be completed before performing recording
circuit adjustment.)
adjustment should be completed before performing recording
circuit adjustment.)
6. The adjustments should be performed for both L-CH and R-
CH.
7. Switches and controls should be set as follows unless otherwise
specified.
• Test Tape
RECORD/PLAYBACK HEAD AZIMUTH ADJUSTMENT
DECK A DECK B
Note: Perform this adjustments for both decks
Procedure:
1. Mode: Playback
Tape
Signal
Used for
P-4-A100
10 kHz, –10 dB
Azimuth Adjustment
set
MAIN board
CN510
Pin
CN510
Pin
1
(L-CH)
Pin
3
(R-CH)
MAIN board
CN510
Pin
CN510
Pin
2
(GND)
+
–
–
level meter
test tape
P-4-A100
(10 kHz, –10 dB)
P-4-A100
(10 kHz, –10 dB)
22
HCD-GNX700/GNX800
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.
so that outputs match within 1dB of peak.
3. Mode: Playback
4. After the adjustments, apply suitable locking compound to
the pats adjusted.
Adjustment Location: Playback Head (Deck A).
Record/Playback/Erase Head (Deck B).
Screw
position
position
L-CH
peak
peak
within
1dB
1dB
Output
level
level
L-CH
peak
peak
R-CH
peak
peak
within
1dB
1dB
Screw
position
position
R-CH
peak
peak
MAIN
board
CN510
set
board
CN510
set
test tape
P-4-A100
(10 kHz, –10 dB)
P-4-A100
(10 kHz, –10 dB)
pin
3
oscilloscope
L-CH
R-CH
V
H
waveform of oscilloscope
in phase 45
°
90
°
135
°
180
°
good
wrong
pin
2
pin
1
L
R
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
3. Use an oscilloscope with more than 10M
Ω 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.
following checks.
S-curve Check
Connection:
Connection:
Procedure:
1. Connect an oscilloscope to test point JPO102 (FE1) and TP
117(VC) on the CD board.
2. Turn the power on.
3. Put the disc (YEDS-18) in and turned power switch on again
3. Put the disc (YEDS-18) in and turned power switch on again
and actuate the focus search. (actuate the focus search when
disc table is moving in and out)
disc table is moving in and out)
4. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within
2.4
± 1 Vp-p.
S-curve waveform
Note:
•
Try to measure several times to make sure than the ratio
of A : B or B : A is more than 10 : 7.
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.
brightness to obtain best waveform.
Checking Location: CD board (SIDE B)
(See page 24.)
+
–
–
CD board
JPO102 (FE1)
TP117 (VC)
oscilloscope
A
B
symmetry
within 2.4
±
1 Vp-p
azimuth
screw
screw
23
HCD-GNX700/GNX800
RFAC Level Check
Connection:
Connection:
Procedure:
1. Connect an oscilloscope to test point TP124 (RFAC) and TP
117(VC) on the CD board.
2. Turn the power on.
3. Put the disc (YEDS-18) in to playback the number five track.
4. Confirm that oscilloscope waveform is clear and check RFAC
3. Put the disc (YEDS-18) in to playback the number five track.
4. Confirm that oscilloscope waveform is clear and check RFAC
signal level is correct or not.
Note:
A clear RFAC signal waveform means that the shape “
◊” can be
clearly distinguished at the center of the waveform.
RFAC signal waveform
Checking Location: CD board (SIDE B)
(See page 24.)
E-F Balance Check
Connection:
Connection:
Procedure:
1. Connect an oscilloscpe to test point TPO103 (TE1) and TP117
(VC) on the CD board.
2. Turn the power on.
3. Select the function “CD”.
3. Select the function “CD”.
4. Press three buttons of [ENTER], M , and
[SURRUUND MODE] simultaneously to set the CD service
mode.
mode.
5. Put the disc (YEDS-18) in to playback the number five track.
6. Press the . button. The message “TRAVERSE” is
displayed. (The tracking servo and the sledding servo are
turned OFF)
turned OFF)
7. Check the level B of the oscilliscope's waveform and the A
(DC voltage) of the center of the Traverse waveform.
Confirm the following :
A/B x 100 = less than
Confirm the following :
A/B x 100 = less than
± 22%
Traverse Waveform
8. Press the . button. The message “TRAVERSE” is
displayed. (The tracking servo and sledding servo are turned
ON)
Confirm the C (DC voltage) is almost equal to the A (DC
voltage) is step 5.
ON)
Confirm the C (DC voltage) is almost equal to the A (DC
voltage) is step 5.
9. To exit from this mode, perform as follows.
1)
Move the optical pick-up to the most inside track.
2) Press three buttons of x , [CLEAR], and [DISPLAY]
simultaneously. (cold reset)
simultaneously. (cold reset)
Notes:
• Always move the optical pick-up to most inside track
when exiting from this mode. Otherwise, a disc will not
be unloaded.
• Do not run the sled motor excessively, otherwise the gear
when exiting from this mode. Otherwise, a disc will not
be unloaded.
• Do not run the sled motor excessively, otherwise the gear
can be chipped.
Traverse Waveform
Checking Location: CD board (SIDE B) (See page 24.)
+
–
–
CD board
TP124 (RFAC)
TP117 (VC)
oscilloscope
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
TIME/DIV: 500 ns
level: 0.9
±
0.4 Vp-p
+
–
–
CD board
JPO103 (TE1)
TP117 (VC)
oscilloscope
0V
B
level: 1.0
±
0.5 Vp-p
Center of
the waveform
the waveform
A (DC
voltage)
0V
Tracking servo
Sled servo
ON
C (DC
voltage)
voltage)
Tracking servo
Sled servo
OFF
24
HCD-GNX700/GNX800
Checking Location:
– CD BOARD (SIDE B) –
TP117 (VC)
TP124 (RFAC)
JPO103 (TE1)
JPO102 (FE1)
IC101
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