NAD T517AHT Service Manual page 22

ELECTRICAL TROUBLESHOOTING GUIDE
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
Proper
NO
RFL signal on
MT1389S?
Check LDO1 & LDO2 signal
Proper
NO
DMSO signal on
MT1389S.
SP+ & SP-
output properly?
Check the cable
connection between spindle
and main PCBA.
3-9
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
Check the laser power circuit
on MT1389S and connecting
to power transistor.
Check the related circuit on
laser power transistor.
Check the related circuit
on MT1389S RFL signal.
Check DMSO related
circuit on MT1389S.
Check the spindle control
amp circuit of motor driver.