Zenith DV140 Service Manual page 17

C
Laser turns on when
reading disc?
YES
Put disc in?
YES
Disc ID is correct?
YES
Does spindle rotate?
YES
D
NO
LD01 or LD02 output
properly?
Collector voltage of
power transistor is OK?
Check cable connection
between transistor ouput
and pick-up head.
NO
Laser off
NO
Proper RFL signal on
MT1389D?
Check LDO1 & LDO2 signal
NO
Proper DMSO signal on
MT1389D
SP+ & SP- output properly?
Check the cable connection
between spindle and main
PCBA.
3-7
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
Check the laser power circuit
on MT1389D and connecting
to power transistor.
Check the related circuit on
laser power transistor
Check the related circuit on
MT1389D RFL signal.
Check DMSO related
circuit on MT1389D.
Check the spindle control
amp circuit of motor driver.