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Text excerpt from page 15 (click to view)
HCD-EP515
SECTION 5 ELECTRICAL ADJUSTMENTS
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� 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.
RFDC signal waveform
VOLT/DIV: 200 mV TIME/DIV: 500 ns
Checking Location: CD board (Conductor side) RFAC Level Check Connection:
oscilloscope CD board
Procedure: 1. Connect an oscilloscope to test point TP (FE) and TP (DVC) on the CD board. 2. Turn the power on. 3. Put the disc (YEDS-18) in and turned power switch on again and actuate the focus search. (actuate the focus search when 4. disc table is moving in and out) Check 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
TP (RFAC) TP (VC)
+ �
Procedure: 1. Connect an oscilloscope to test point TP (RFAC) and TP (VC) on the CD board. 2. Turn the power on. 3. Put the disc (YEDS-18) in to playback the number five track. 4. Confirm that oscilloscope waveform is clear and check RFAC signal level is correct or not.
Note: A clear RFAC signal waveform means that the shape ��� can be clearly distinguished at the center of the waveform.
symmetry
RFAC signal waveform
A within 2 ± 1 Vp-p B
VOLT/DIV: 200 mV TIME/DIV: 500 ns
level: 1.35 ± 0.4 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.
Checking Location: CD board (Conductor side) RFDC Level Check Connection:
oscilloscope CD board TP (RFDC) TP (DVC)
+ �
Checking Location: CD board (Conductor side) (See page 14)
Procedure: 1. Connect an oscilloscope to test point TP (RFDC) and TP (DVC) on the CD board. 2. Turn the power on. 3. Put the disc (YEDS-18) in to playback the number five track. 4. Confirm that oscilloscope waveform is clear and check RFDC signal level is correct or not.
Note: A clear RFDC signal waveform means that the shape ��� can be clearly distinguished at the center of the waveform.
