CX-JS3
17
17
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 : 1.0
±
0.3Vp-p
SECTION 5
ELECTRICAL ADJUSTMENTS
CD TEST MODE
• This mode can run the CD sled motor freely. Use this mode, for
instance, when cleaning the pickup.
Procedure:
1. In the status where AC plug is disconnected, while pressing
the
[CD]
button, connect the AC plug to turn the power on.
2. When enter this mode, it displays “CD TEST” and few sec-
onds later, all segments turn on of the fluorescent indicator
tube.
3. To release from this mode, disconnect the AC plug and turn
the power off.
In this mode, it operates as following table.
Button
Operation
Purpose of use
M
Move the pick-up to outside track
Sled circuit check
m
Move the pick-up to inside track
Tracking circuit check
Mechanism operation check
Optical pick-up check
N
Playback a CD
Servo block check
If it cannot focus on, it continuous focus search
x
When playback a CD: stop playback
APC circuit check
When stop a CD:
Laser current measure
display “READING” (blink)
Focus search waveform check
continuous laser diode on
Tracking balance check
continuous focus search (not made focus on)
X
Pause, Tracking servo off
(ignore CLV error)
TP (VC)
TP (RF)
TP (FE)
IC721
– BD Board (Conductor side) –
