LG CD-372A Service Manual page 10

When laser does not light
A
Does lenses move up and down?
YES
YES
Has Pick-up returned to the
innermost position?
YES
Does pick-up stop after having
moved to the innermost
position?
Dose generate about 2.5V at
IC601 Pin18 (LD)?
YES
Has laser power source returned to
the Q601
(Q601 collector voltage about 1.8V)
YES
Flow laser current?
Both voltage of R610 is about 0.7V?
NO
Are data transterred from
IC 701?
YES
Is below signal output at
IC603 Pin17,18 ?
YES
NO
YES
NO
NO
»
R610 0.7V
NO
«
R610 0.7V
- 2-5 -
NO
• IC701 defective.
NO
• IC 601, 603 defective.
• Slide motor defective.
• Connector defective.
• IC603 defective.
• connector defective.
• IC602 defective.
• IC601 defective.
• Surrounding Circuitry defective.
• Connector defective.
YES • Q601 defective, connector
defective.
• Laser defective.
YES
• Laser defective.
• connector defective, short etc.