Method For Diagnosing Degradation Of The Lds On The Pickup Assy - Pioneer XV-DV740 Service Manual

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7.1.8 METHOD FOR DIAGNOSING DEGRADATION OF THE LDS ON THE PICKUP ASSY

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3 7 63 1515 0
Case when this diagnosis is required :
When playback of any disc, including a test disc (DVD: GGV1025, CD: STD-905), cannot be performed
How to diagnose
In the case mentioned above, degradation of the laser diodes (LDs) mounted on the PICKUP Assy is suspected.
Measure the voltage between the two ends of one of the resistors mentioned below.
No playback of a DVD :
Measure the voltage between the two ends of R201 on the DVDM Assy. If the
voltage is 0.7 V or higher, the 650-nm LD is degraded.
No playback of a CD :
Measure the voltage between the two ends of R211 on the DVDM Assy. If the
voltage is 1.5 V or higher, the 780-nm LD is degraded.
B
DVDM ASSY
TE
L 13942296513
Front side
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PICKUP ASSY
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3 6 7 1 3 1 5
CN104
24
1
24
23
R102
R101
1
R220
R221
R222
42
C222
R223
C306
co
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XV-DV740
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8
9 4 2 8
If the measurements show degradation
of an LD, replace the PICKUP Assy.
CN101
0 5 8 2 9 9 4 2 8
C
CN101
1
2
CN121
1
IC201
GNDD
LD1
(650)
(780)
Q201
R202 R212
R391
m
9 9
A
B
C
9 9
D
V+5D
LD2
Q211
E
F
95
8