Electrical Adjustments - Sony HCD-GX450 Service Manual

HCD-GX450
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 10MΩ 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
BD board (New type model)
BD81A board (Old type model)
TP(FE)
TP(VC)
Procedure:
1. Connect an oscilloscope to TP (FE) and TP (VC) on the BD
board (New type model) or BD81A board (Old type model).
2. Press the button to turn the power on.
I/1
3. Load the 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 2 ± 1 Vp-p.
S-curve waveform
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.
Connecting Location: BD board (Side B)(New type model)
BD81A board (Side B)(Old type model)
RFAC LEVEL CHECK
BD board (New type model)
BD81A board (Old type model)
TP(RFACO)
TP(VC)
Procedure:
1. Connect an oscilloscope to TP (RFACO) and TP (VC) on the
BD81A board.
2. Press the button to turn the power on.
I/1
3. Load the disc (YEDS-18) and playback.
4. Confirm that oscilloscope waveform is clear and check if RFAC
signal level is correct or not.
Note: Clear RFAC signal waveform means that the shape " ◊ " can be clearly
distinguished at the center of the waveform.
Connecting Location: BD board (Side B)(New type model)
BD81A board (Side B)(Old type model)
16
SECTION 3

ELECTRICAL ADJUSTMENTS

oscilloscope
symmetry
A
within 2 ± 1 Vp-p
B
oscilloscope
RF signal waveform
– BD BOARD (Side B)(New type model) –
– BD81A BOARD (Side B)(Old type model) –
TP
(VC)
TP
(FE)
VOLT/DIV : 200 mV
TIME/DIV : 500 ns
level : 1.0 ± 0.4 Vp-p
IC101
TP
(RFACO)