LG RH7521W Service Manual page 78

LD CHECK
(Laser operating is abnormal)
Perform 6. Optical Power Setting parameter
check from'How to use Test tool'.
Is ALPC parameters
valid?
Perform 4. LD Test check from
'How to use Test tool'.
OFF level
VRDC level &FPD
VWDC1 level &FPD
VWDC2 level &FPD
OK
FPD
VRDC
Execute "C.Laser Power Setup"of
"How to use Test Tool"
Check reference voltage.
E
F
G
VWDC2
VWDC1