36
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 fol-
lowing checks.
S-Curve Check
Procedure :
1. Connect oscilloscope to TP (FEO).
2. Connect between TP (FEI) and TP (VC) by lead wire.
3. Connect between TP (AGCCON) and TP (GND) by lead wire.
4. Turn
?/1
button on.
5. Load a disc (YEDS-18) and actuate the focus search. (In conse-
quence of open and close the disc tray, actuate the focus search)
6. Confirm that the oscilloscope waveform (S-curve) is symmetri-
cal between A and B. And confirm peak to peak level within 4
±1 Vp-p.
7. After check, remove the lead wire connected in step 2 and 3.
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
Procedure :
1. Connect oscilloscope to TP (RF).
2. Connect between TP (AGCCON) and TP (GND) by lead wire.
3. Turned
?/1
button on.
4. Load a disc (YEDS-18) and playback.
5. Confirm that oscilloscope waveform is clear and check RF sig-
nal level is correct or not.
6. After check, remove the lead wire connected in step 2.
BD board
Oscilloscope
TP(FEO)
TP(VC)
Symmetry
S-curve waveform
Wthin 4
±
1Vp-p
A
B
TP(RF)
TP(VC)
BD board
Oscilloscope
Note :
Clear RF signal waveform means that the shape “
◊
” can be
clearly distinguished at the center of the waveform.
E-F Balance (1 Track jump) Check
Procedure :
1. Connect oscilloscope to TP (TEO) and TP (VC).
2. Turned
?/1
button on.
3. Load a disc (YEDS-18) and playback the number five track.
4. Press the
u
button. (Becomes the 1 track jump mode.)
5. Confirm that the level B and A (DC voltage) on the oscillo-
scope waveform.
6. After check, remove the lead wire connected in step 1.
Adjustment Location:
[BD (CD) BOARD]
(Conductor Side)
RF signal waveform
VOLT/DIV : 200mV
TIME/DIV : 500ns
Level : 1.45
±
0.3Vp-p
TP(TEO)
TP(VC)
BD board
Oscilloscope
Level=1.3
±
0.6 Vp-p Symmetry
A (DC voltage)
Center of
waveform
B
0 V
1 track jump waveform
Specified level:
×
100 = less than
±
22 %
B
A
TP (RF)
TP (VC)
IC103
IC101
TP (TEO)
TP (FE0)
TP (AGCCON)
TP
(GND)
Summary of Contents for HCD-VZ50MD
Page 8: ...8 BD CD board BD CD BOARD To repair the BD CD board remove the bottom plate Bottom view ...
Page 57: ...HCD VZ50MD 57 57 7 4 SCHEMATIC DIAGRAM DECK SECTION E Page 64 TO MAIN BOARD 16 ...
Page 64: ...HCD VZ50MD 64 64 7 11 SCHEMATIC DIAGRAM MAIN 1 4 SECTION ...
Page 65: ...HCD VZ50MD 65 65 7 12 SCHEMATIC DIAGRAM MAIN 2 4 SECTION See page 89 for IC Block Diagrams ...
Page 67: ...HCD VZ50MD 67 67 7 14 SCHEMATIC DIAGRAM MAIN 4 4 SECTION See page 89 for IC Block Diagrams ...
Page 71: ...HCD VZ50MD 71 71 7 18 SCHEMATIC DIAGRAM DIGITAL 2 2 SECTION See page 92 for IC Block Diagrams ...
Page 73: ...HCD VZ50MD 73 73 7 20 SCHEMATIC DIAGRAM AMP SECTION ...
Page 77: ...HCD VZ50MD 77 77 7 24 SCHEMATIC DIAGRAM SWITCH SECTION ...
Page 83: ...HCD VZ50MD 83 83 7 32 SCHEMATIC DIAGRAM POWER SUPPLY SECTION ...