HCD-PX333
CD SECTION
Note:
1.CD Block is basically designed to operate without adjustment. There- fore, check each item in order given.
2.Use
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.
5.Level doesn’t change whichever with normal speed or with four times speed.
6.Use the following jig.
•Extension jig (21 core) (Part No.
CN101 on the BD (CD) board to CN1002 on the MD DIGITAL board
Note: A clear RF signal waveform means that the shape “◊” can be clearly distinguished at the center of the waveform.
RF signal waveform
VOLT/DIV: 200 mV
TIME/DIV: 500 ns (normal speed)
level: 1.2 ±0.2
S Curve Check
Connection:
oscilloscope (DC range)
BD (CD) board
TP (FE) 
+
TP (VC) 
–
Procedure:
1.Connect an oscilloscope to test point TP (FE) and TP (VC) on the BD (CD) board.
2.Turn the power on.
3.Put the disc
4.Check the oscilloscope waveform
symmetry | |||
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A
within 3.6 ± 0.5
B
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: BD (CD) board
RF Level Check
Connection:
oscilloscope
(AC range)
BD (CD) board
TP (RF) | + |
TP (VC) | – |
Procedure:
1.Connect an oscilloscope to test point TP (RF) and TP (VC) on the BD (CD) board.
2.Turn the power on.
3.Put the disc
4.Confirm that oscilloscope waveform is clear and check RF sig- nal level is correct or not.
Checking Location: BD (CD) board
E-F Balance Check
Connection:
oscilloscope (DC range)
BD (CD) board
TP (TE) | + |
TP (VC) | – |
Procedure:
1.Connect an oscilloscpe to test point TP (TE) and TP (VC) on the BD (CD) board.
2.Turn the power on.
3.Put the disc
4.Press the [REPEAT STEREO/MONO] button. (The tracking servo and the sledding servo are turned OFF)
5.Check the level B of the oscilliscope's waveform and the A (DC voltage) of the center of the Traverse waveform.
Confirm the following :
A/B x 100 = less than ± 22%
| Traverse Waveform |
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| B |
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0V |
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| A | ||
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| level: 1.3 ± 0.6 | |||||||
6.Press the [REPEAT STEREO/MONO] button. (The tracking servo and sledding servo are turned ON)
Confirm the C (DC voltage) is almost equal to the A (DC volt- age) is step 5.
Traverse Waveform
0V |
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| Tracking servo |
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| Tracking servo | ||||||
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| Sled servo |
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| Sled servo | |||
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| OFF |
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| ON | |||||
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Checking Location: BD (CD) board
48
