Sony MCE-K700, Service Manual

Page: 18 / 66

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SECTION 5
ELECTRICAL ADJUSTMENTS
Note : A clear RF signal waveform means that the shape “
◊
” can be
clearly distinguished at the center of the waveform.
RF signal waveform
BD board
TP (FE)
TP (VC)
BD board
TP (RF)
TP (VC)
VOLT/DIV : 200mV
TIME/DIV : 500ns
level : 1.3 p-p
TP (TE)
TP (VC)
BD board
0V
C (DC
voltage)
Tracking servo
Sled servo
ON
Tracking servo
Sled servo
OFF
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
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.
S Curve Check
Procedure :
1. Connect oscilloscope to test point TP (FE) on BD board.
2. Connect between test point TP (FEI) and TP (VC) by lead wire.
3. Turned Power switch on.
4. Put 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.)
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
within 3
±
1 Vp-p
A
B
6. After check, remove the lead wire connected in step 2.
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 bright-
ness to obtain best waveform.
RF Level Check
Procedure :
1. Connect oscilloscope to test point TP (RF) on BD board.
2. Turned 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 signal
level is correct or not.
E-F Balance (Traverse) Check
Procedure :
1. Connect oscilloscpe to test point TP (TE) on BD board.
2. Turned Power switch on.
3. Connect the SL502 and SL503 on the VIDEO board with solder.
4. Put disc (YEDS-18) in to play the number five track.
5. Press the KARAOKE STAR button. (The tracking servo and the
sledding 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 :
A/B x 100 = less than
±
22%
Traverse waveform
8. Remove the soldering installed in step 3.
oscilloscope
oscilloscope
+0.25
–0.20
oscilloscope
7. Press the KARAOKE STAR 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
0V
Center of the waveform
B
A (DC voltage)
level : 1.3
±
0.6 Vp-p