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INSTRUCTIONS ON CD PLAYABILITY
EYE-PATTERN SIGNAL – JITTER MEASUREMENT
Measure the signal on the input of the Signal processor
using an analog oscilloscope. Please find the exact
measuring point in your Service Manual.
EYE-PATTERN
800mVpp
TB = 0.5µs/div
HF-Amplifier
+5V_HF
2,4V
7876
2883
3903
BC847B
3901
3K3
470n
1,8V
Σ (A-D)
560R
1,2V
2881
0,65V
560p
BC847B
See below examples of the signal. Amplitude should read at
least 700mVpp using SBC444A.
If the oscilloscope shows a signal like the 'bad' one, and/or
the amplitude decreases within 1 minute - the CD drive has
to be replaced.
5
11
D4
D3
10
D3
D2
9
D2
D1
8
D1
3893
VrefCD10
7
VRIN
470R
3895
6
IREF
27K
3896
+3.3V
5
VDDA1
100R
4
VSSA1
3
ISLICE
2813
3898
2
HFIN
HFIN
220R
4n7
3904
1
HFREF
3K3
LD
LD
ON
470R
to 3826,3827
3899
3906
2,6V
CD_DA: 0V / CD_RW: 3V
2K7
3923
7878
+3.3V
BC847B
7877
10K
Sanyo
DA12T3
Drive detection
good
bad
1-8
CD DRIVE – LASER CURRENT MEASUREMENT
The laser current can be measured as a voltage drop on a
resistor. The resistor is marked in every Service Manual.
The value depends on the type of CD drive.
VAMxxxx
MCDxx
DA1x
VREF GE
DA2x
Use SBC444A (CD-DA) for measurement.
+5V_HF
ON
64
LASER DIODE
CD DRIVE – OFFSET MEASUREMENT
The photodiodes of the CD-drive may have an offset. These
offsets have to be compensated by the signal processor.
High offsets can lead to poor playability of some CDs
(skipping tracks).
To measure the offset values, start the Service Test
Program - section "Focus Test" without a CD.
The offsets can be measured with a DC Millivoltmeter
directly on the connector (see drawing below). Pin
numbering varies from drive to drive.
The values from diode A-D should read 0±10mV.
Diodes E and F are less critical.
CD Drive
Sanyo DA12T3
E
B
A
C
D
F
If one of the offsets is higher than ±10mV the CD drive has
to be replaced. Otherwise replace the Signal Processor.
6
typical value
most probably defect
≥350mV
: 150-230mV
≥300mV
: 170-230mV
≥350mV
: 210-250mV
≥250mV
: 175-200mV
Laser power control
U >250mV
->Laser damaged !
3820
4R7
3,9V
3823
3,3V
7879
1K
BC807-40
2V
7
1800
16
VREF
15
VCC
E
14
E
13
D
D
12
A
A
11
B
B
10
C
C
9
F
8
GND
+5V
4,6V
7811-A
3
0,17V
8
LM358D
1
3V
2
0,17V
4
VrefCD10
+5V_HF
E
D
A
B
C
F
F
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