LG FFH-185A Service Manual page 11

A
Laser does not light.
Is "3.5V" applied to pin
YES
Did pickup return to
innermost circular?
YES
Does it stop at inner pick
circular after shift?
YES
Is power supplied to laser Q501?
(Q 501 collector: about 1.8V)
YES
Does laser current flow?
1.0V across R507
of IC 501?
70
NO
NO
Is data transferred from
MICOM IC ?
Does voltage appear at IC
502 pin
Is defect output from LM
SW applied to pin
PN503?
YES
OPEN
NO
YES
NO
, ?
17 18
YES
of
5
CLOSE
YES
NO
»
YES
R507 1.0V
YES
«
R507 1.0V
- 2-5 -
Defective MICOM.
Defective IC 501, 502
Defective slide motor and/or
connector.
NO
Defective LMT SW and/or
connector.
Defective MICOM.
Defective connector.
Defective Q 501 and/or laser.
Defective laser and/or
connector.