Diagnosis; Method For Diagnosing Degradation Of The Lds On The Pickup - Pioneer XV-DV575 Service Manual

5

5. DIAGNOSIS

5.1 METHOD FOR DIAGNOSING DEGRADATION OF THE LDS ON THE PICKUP

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 PCB 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 R322 or R325 on the 08 DVDM
Assy. If the voltage is 0.4 V or higher, the 650-nm LD is degraded.
No playback of a CD :
Measure the voltage between the two ends of R321 or R326 on the 08 DVDM
Assy. If the voltage is 0.4 V or higher, the 780-nm LD is degraded.
Q305
Q304
R326
UP SIDE
L308
1 5 10 15 20
5
6
C309
R154
R313
R322 D
D
C372
R322
Q307
CONTACT
SIDE
CONTACT
1 5 1
CN102 CN104
SIDE
6
7
If the measurements show degradation
of an LD, replace the DVD MECHA
Assy.
A
R326
C140
C
5
XV-DV575
7
8
08 DVDM ASSY
SIDE A
8
A
B
C
D
E
F
19