Denon DVD-A1 - IOP Measurement (Judging for Traverse Unit Replacement)

3
DVD-9000/DVD-A1
Laser current initial value on the rear of mechanism
DVD mA
CD mA
1
1
1
2
4
1
1
1
1
1
115
1
1
20 21
40
45
8
1
6
717
18
28
29 39
40
16
1732
7
814
11
12
24
25 36
37
48
25
26
50
5175
76
100
20
2140
20
21
40
41
60
61
80
14
15
28
DVD laser drive current measuring points
Nearby C532
CD laser drive current measuring points
[CD] IOP silk point
GU-3389 P.W.B. (foil side)
(1) DVD laser drive current measurement
• Playback the title-1/chapter-1 of DVDT-S01 or commercially available DVD disc.
• Connect an oscilloscope to the test point above and measure the voltage.
• DVD laser drive current is calculated by:
Iop = Measured Voltage Value / 39 (Resistance Value)
(2) CD laser drive current measurement
• Playback the track-1 of TCD-784 or commercially available CD disc.
• Connect an oscilloscope to the test point above and measure the voltage.
• CD laser drive current is calculated by:
Iop = Measured Voltage Value / 39 (Resistance Value)
Iop Measurement (Judging for Traverse Unit Replacement)
As to deciding whether optical pickup is defect or not (for replacing traverse unit), follow the steps below.
1. Judging Step
(1) Disc play abnormal
Problems such as disc no read, unsteady playback, etc.
(2) Laser drive current (Iop) check
Check Iop according to the measuring method described in step 2 below.
If the checked value is 1.5 times or more than the initial Iop indicated
on the rear of mechanism unit, the traverse unit should be replaced.
(3) Replacing traverse unit
Referring to “How to Replace Traverse Unit”, replace the traverse unit.
No mechanism adjustment is required as the whole unit is replaced with
a new one.
2. Iop Measuring Method