Electrical Adjustments - Sony CDP-CX70ES Service Manual

SECTION 6
ELECTRICAL ADJUSTMENTS
Note:
I.
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 lOMQ 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.
S-Curve Check
osct/loscope
BD{~oard~
TP{FE1) +
TP{VC) -
Procedure:
1. Connect oscilloscope to test point TP (FE1) on BD (TEXT)
board.
2. Connect test point TP301 (ADJ) on MAIN board to ground with
lead wire.
3. Tum POWER switch on to set the ADJ mode.
4. Put disc (YEDS-18) in and playback.
Press the CHECK button.
5. Check the oscilloscope waveform (S-curve) is symmetrical be-
tween A and B. And confirm peak to peak level within 3±1 Vp-p.
S-curve waveform
symmetry
Wtthm 3
±
1 Vp-p
6. After check, remove the lead wue connected in step 2.
Note : • Try to measure several times to make sure than the ratio of
A : B orB : A is more than 10 : 7.
• Take sweep time as long as possible and light up the bright-
ness to obtain best waveform.
RF Level Check
osctlloscope
BD{~oard~
TP{RF) +
TP{VC) -
Procedure:
I. Connect oscilloscope to test point TP (RF) on BD (TEXT) board.
2. Tum POWER switch on.
3. Put disc (YEDS-18) in to play the number five track.
4. Confirm that oscilloscope waveform is clear and check RF sig-
nallevel is correct or not.
Note: A clear RF signal waveform means that the shape "0" can
be clearly distinguished at the center of the waveform.
RF signal waveform
VOLT/0/V · 200mV
I
TIME/0/V. 500ns
fever · 1
2
~ ~g
Vp-p
V'-fVVVVVV.J\.AAA.IVV
E-F Balance Check
osctlloscope
BD{~oa~rd
TP{TE)
+
TP(VC) -
Procedure:
1. Connect oscilloscpe to test point TP (TE) on BD (TEXT) board.
2. Connect the test point TP30l (ADJ) on MAIN board to the
ground with a lead wire.
3. Tum the POWER switch on to set the ADJ mode.
4. Put disc (YEDS-18) in to play the number five track.
5. Press the "GROUP 3" button. (The tracking servo and the sled-
ding servo are turned OFF.)
6. Check the level B of the oscilliscope's waveform and the A (DC
voltage) of the center of the Traverse waveform.
Confirm the following :
AlB x 100
=
less than ± 22%
Traverse waveform
Center of the waveform
level 1 3
±
0.6 Vp-p
7. Press the "GROUP 8" button. (The tracking servo and sledding
servo are turned ON.) Confirm the C (DC voltage) is almost
equal to the A (DC voltage) is step 6.
Traverse waveform
Trackmgse~
Sfeddmg
servo
OFF
Trackmg servo
Sleddmg servo
ON
C{DC
voltage)
8. Disconnect the lead wire ofTP301 (ADJ) connected m step 1.
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