NAD T515AH, Service Manual, Page: 18 / 51

3-7
C
LD_DVD or LD_CD
output properly? Laser turns on when
reading disc?
Put disc in?
Disc ID is correct?
Does spindle rotate?
D
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
Check the laser power circuit
on ZR36888 and connecting
to power transistor.
NO
Collector voltage of power
transistor is OK? Check the related circuit on
laser power transistor
NO
Check cable connection
between transistor ouput
and pick-up head.
YES
YES
YES
Check the related circuit
on ZR36888 RFL signal.
Check SPINDLE_S related
circuit on ZR36888.
NO
NO
Check the spindle control
amp circuit of motor driver.
NO
Laser off
Proper RF signal on
ZR36888?
Check LD_DVD & LD_CD
signal
Proper SPINDLE_S signal
on ZR36888
SP+ & SP- output properly?
Check the cable connection
between spindle and main
PCBA.