Cd Section - Sony HCD-F250AV Service Manual

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 :
Press the 1/u button to turn ON the power .
1.
2. Open the front cover, and press the CD PLUS ONE button.
3. Set the disc (YEDS-18) into the "PLUS ONE" slit.
4. Close the front cover, and chuck the disc.
Press the 1/u button to turn OFF the power.
5.
6. Connect the oscilloscope to TP (FE) of the BD board.
7. Connect TP (ADJ) of the MAIN board and connect TP (GND)
with a lead wire.
Press the 1/u button to turn ON the power.
8.
9. The first track will be played back automatically. When the
CHECK button is pressed, "S JI" will be displayed on the
fluorescent indicator tube, and focus search will be repeated.
10. Check the oscilloscope waveform (S-curve) is symmetrical
between 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 :
Press the 1/u button to turn ON the power.
1.
2. Open the front cover, and press the CD PLUS ONE button.
3. Set the disc (YEDS-18) into the "PLUS ONE" slit.
4. Close the front cover, and chuck the disc.
Press the 1/u button to turn OFF the power.
5.
6. Connect the oscilloscope to TP (RF) of the BD board.
7. Connect TP (ADJ) of the MAIN board and connect TP (GND)
with a lead wire.
Press the 1/u button to turn ON the power.
8.
9. Playback the fifth track of the disc.
oscilloscope
symmetry
A
within 1.8 ± 0.6Vp-p
B
oscilloscope
— 24 —
10. Confirm that oscilloscope waveform is clear and check RF signal
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 general
remote control unit is used and not used.
BD board
TP (TE)
TP (VC)
When a general remote commander is used:
Press the 1/u button to turn ON the power.
1.
2. Open the front cover, and press the CD PLUS ONE button.
3. Set the disc (YEDS-18) into the "PLUS ONE" slit.
4. Close the front cover, and chuck the disc.
Press the 1/u button to turn OFF the power.
5.
6. Connect the oscilloscope to TP (TE) of the BD board.
7. Connect TP (ADJ) of the MAIN board and connect TP (GND)
with a lead wire.
Press the 1/u button to turn ON the power.
8.
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
0V
Tracking servo
Sled servo
OFF
13. Turn OFF the power, and remove the lead wire connected at
step 7.
VOLT/DIV : 200mV
TIME/DIV : 500ns
+0.3
level : 1.8 ±
Vp-p
–0.2
oscilloscope
Center of the waveform
B
A (DC voltage)
level : 0.7 ± 0.3 Vp-p
C (DC
voltage)
Tracking servo
Sled servo
ON