Note:Clear RF signal waveform means that the shape a� can beO
CD SECTION
clearly distinguished at the center of the waveform.
Note:
RF signal waveform
1. CD Block is basically constructed to operate without
adjustment. Therefore, check each item in order given.
VOLT/DIV : 200mV
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.TIME/DIV : 500ns
3. Use an oscilloscope with more than 10MW impedance.
4. Clean the object lens by an applicator with neutral detergent
when the signal level is low than specified value with thelevel : 1.75 ? 0.25 Vp-p
following checks.
S Curve Check
E-F Balance (Traverse) Check
oscilloscope
oscilloscope
BD board
BD board
TP (FE)+
TP (VC)�TP (TE)+
TP (VC)�
Adjustment Location: BD board
Adjustment Location: BD board
Procedure :
1. Connect the oscilloscope to test points TP (FE) and ProcedurTP (VC).e :
2. Connect TP (FEI) and GND, and TP (AGCCON) and GND of1. Connect oscilloscpe to test point TP (TE) on BD board.
the BD board with lead wires.2. Short-circuit SL502 of the video board to GND.
3. Press the 1/u button to turn the set ON.3. Turned Power switch on. Press FUNCTION button to select
4. With the disc (YEDS-18) loaded^, press the button andCD.
perform focus search. (Focus search will be perf4. orPut disc (YEDS-18) in to play the number fmed in theive track.
same way even while the disc table is pushed in and out.)5. Press the PLAY MODE button. (The tracking servo and the
5. Check the symmetry and peak to peak level of the oscilloscopesledding servo are turned OFF.)
waveform (S curve) at this time.6. Check the level B of the oscilliscope's waveform and the A
(DC voltage) of the center of the Traverse waveform.
S-curve waveformConfirm the following :
symmetryA/B x 100 = less than ? 22%
Traverse waveform
Center of the waveform
A
Within 4.0 ? 1.0 Vp-p
B
B
0VA (DC voltage)
6. After check, remove the lead wire connected in step 2.
Note: Y Try to measure several times to make sure than the ratio
of A : B or B : A is more than 10 : 7.level : 1.3 ? 0.6 Vp-p
Y Take sweep time as long as possible and light up the
brightness to obtain best waveform.7. Press the PLAY MODE button. (The tracking servo and
sledding servo are turned ON.) Confirm the C (DC voltage) is
Adjustment Location: BD boardalmost equal to the A (DC voltage) is step 7.
Traverse waveform
RF Level Check
oscilloscope
BD board
C (DC
TP (RF)+0Vvoltage)
TP (VC)�
Tracking servoTracking servo
Procedure :Sled servoSled servo
1. Connect oscilloscope to test point TP (RF) and TP (VC) on OFF ON
BD board.
2. Connect TP (AGCCON) and GND of the BD board with lead8. Desolder the short-land (SL502) short-circuited at step 2.
wires.
Adjustment Location: BD board
3. Press the 1/u button to turn the set ON.
4. Put disc (YEDS-18) in and playback 5track.
5. Confirm that oscilloscope waveform is clear and check RF
signal level is correct or not.
6. After check, remove the lead wire connected in step 2.
18 |
ACEC
SONY
