Mechanical Adjustments; Electrical Adjustments - Sony CFD-G700CP Service Manual

SECTION 5

MECHANICAL ADJUSTMENTS

• Precaution
1. Clean the following parts with a denatured-alcohol-moistened
swab :
record/playback head
erase head
capstan
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
Torque meter
Mode
FWD
CQ-102AS
FWD
CQ-102C
back tension
FF CQ-201AS
REW CQ-201B
• Tape Tension Measurement
Mode Tension Meter
FWD CQ-403A
pinch roller
rubber belts
idlers
Meter reading
2.0 – 8.0 mN • m
(20 to 80 g • cm)
(0.28 – 1.12 oz • inch)
0.15 – 0.6 mN • m
(1.5 to 6 g • cm)
(0.021 – 0.083 oz • inch)
5 – 17.7 mN • m
(50 to 177 g • cm)
(0.7 – 2.48 oz • inch)
5 – 17.7 mN • m
(50 to 177 g • cm)
(0.7 – 2.48 oz • inch)
Meter Reading
more than 80 g • cm
(more than 2.82 oz • inch)
CFD-G700CP/G770CP/G770CPK
SECTION 6

ELECTRICAL ADJUSTMENTS

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 MΩ 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
BD90 board
TP (RFI)
TP (VC)
Procedure :
1. Connect oscilloscope to TP (RFI) and TP (VC) on the BD90
board.
2. Press the POWER button to turn the power ON, and press
the Z PUSH OPEN/CLOSE button to open the CD disc tray.
3. Set disc (YEDS-18) on the tray and press the u (CD) 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.
Checking Location:
– BD90 Board (Side B) –
TP
(VC)
TP
(RFI)
IC101
oscilloscope
(DC range)
+
–
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
1.2 ± 0.3 Vp-p
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