Cd Section - Sony HCD-F50 Service Manual

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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 10MΩ 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.
BD board
TP (FE)
TP (VC)
S Curve Check
Procedure :
1. Press the POWER button to turn ON the power .
2. Open the front cover, and press the CD PLUS1 button.
3. Set the disc (YEDS-18) into the "PLUS ONE" slit.
4. Close the front cover, and chuck the disc.
5. Press the POWER button to turn OFF the power.
6. Connect the oscilloscope to TP (FE) of the BD board.
7. Connect CN404 pin 2 of the MAIN board and the ground
(CN404 pin 1 or 3) with a lead wire.
8. Press the POWER button to turn ON the power.
9. The first track will be played back automatically. When the
CHECK button is pressed, "S JI" will be displayed on the fluo-
rescent indicator tube, and focus search will be repeated.
10. Check the oscilloscope waveform (S-curve) is symmetrical be-
TE
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tween A and B. And confirm peak to peak level within 1.8 ± 0.6
Vp-p.
S-curve waveform
11. Turn OFF the power, and remove the lead wire connected at
step 7.
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
BD board
TP (RF)
TP (VC)
Procedure :
1. Press the POWER button to turn ON the power.
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2. Open the front cover, and press the CD PLUS1 button.
3. Set the disc (YEDS-18) into the "PLUS ONE" slit.
4. Close the front cover, and chuck the disc.
5. Press the POWER button to turn OFF the power.
.
6. Connect the oscilloscope to TP (RF) of the BD board.
7. Connect CN404 pin 2 of the MAIN board and the ground
(CN404 pin 1 or 3) with a lead wire.
8. Press the POWER button to turn ON the power.
9. Playback the fifth track of the disc.
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oscilloscope
symmetry
A
within 1.8 ± 0.6Vp-p
B
oscilloscope
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10. Confirm that oscilloscope waveform is clear and check RF sig-
nal level is correct or not.
11. Turn OFF the power, and remove the lead wire connected at
step 7.
Note : A clear RF signal waveform means that the shape "◊" can
be clearly distinguished at the center of the waveform.
RF signal waveform
E-F Balance (Traverse) Check
The procedure for this checking method differs for when a gen-
eral remote control unit is used and not used.
BD board
TP (TE)
TP (VC)
When a general remote commander is used:
1. Press the POWER button to turn ON the power.
2. Open the front cover, and press the CD PLUS1 button.
3. Set the disc (YEDS-18) into the "PLUS ONE" slit.
4. Close the front cover, and chuck the disc.
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5. Press the POWER button to turn OFF the power.
6. Connect the oscilloscope to TP (TE) of the BD board.
7. Connect CN404 pin 2 of the MAIN board and the ground
(CN404 pin 1 or 3) with a lead wire.
8. Press the POWER button to turn ON the power.
9. Playback the fifth track of the disc.
10. Press the 3 button on the remote commander. (The tracking
servo and the sledding servo are turned OFF.)
11. 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 ± 10%
Traverse waveform
0V
12. Press the 8 button on the remote control unit. (The tracking
servo and sledding servo are turned ON.) Confirm the C (DC
voltage) is almost equal to the A (DC voltage) is step 11.
Traverse waveform
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0V
.
Tracking servo
Sled servo
13. Turn OFF the power, and remove the lead wire connected at
step 7.
– 42 –
2 9 9 4 2 8
VOLT/DIV : 200mV
TIME/DIV : 500ns
+0.3
level : 1.8 ± Vp-p
–0.2
oscilloscope
1 5 0 5 8 2 9 9 4
Center of the waveform
B
A (DC voltage)
level : 0.7 ± 0.3 Vp-p
m
co
Tracking servo
Sled servo
OFF ON
9 9
2 8 9 9
C (DC
voltage)