![background image](http://html.mh-extra.com/html/sony/cx-jt7/cx-jt7_service-manual_420493021.webp)
CX-JT7
21
21
CD SECTION
Note:
1.
CD Block is basically designed to operate without adjustment. Therefore,
check each item in order given.
2.
Use YEDS-18 (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 an oscilloscope to TP (FE) and TP (VC).
2. Turn the power on.
3. Load a disc (YEDS-18) and actuate the focus search. (In
consequence of open and close the disc tray, actuate the focus
search)
4. Confirm that the oscilloscope waveform (S-curve) is
symmetrical between A and B. And confirm peak to peak level
within 3
±
0.5 Vp-p.
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 an oscilloscope to TP (RF) and TP (VC).
2. Turn the power on.
3. Load a disc (YEDS-18) and playback.
4. Confirm that oscilloscope waveform is clear and check if RF
signal level is correct or not.
BD board
Oscilloscope
TP(FE)
TP(VC)
symmetry
S-curve waveform
within 3
±
0.5Vp-p
A
B
TP(RF)
BD board
oscilloscope
TP(VC)
Note:
Clear RF signal waveform means that the shape “
◊
” can be clearly
distinguished at the center of the waveform.
Connecting Location: BD board
RF signal waveform
VOLT/DIV : 200mV
TIME/DIV : 500ns
level : 1.3
±
0.3Vp-p
TP (VC)
TP (RF)
TP (FE)
IC721
– BD Board (Conductor side) –
SECTION 5
ELECTRICAL ADJUSTMENTS
Summary of Contents for CX-JT7
Page 91: ...91 CX JT7 MEMO ...