LG HT904TA Service Manual page 16

A
YES
Power On.
YES
Show LOGO?
YES
Does Tray
move inside when it
is not at closed
position?
YES
B
Flash
NO
Memory operates
properly?
YES
SDRAM
works properly?
YES
MT1389MH
VIDEO outputs
properly?
YES
Check AV cable
connection to TV set.
Normal
NO
OPEN_SW,
CLOSE_SW
signal?
YES
Normal
TROPEN & TRCLOSE
signal?
YES
Normal
LOAD+ & LOAD-
signal?
YES
Check AV cable connection
between main PCBA and
loader. (MECHA)
2-
Check connection lines
NO
between FLASH & MT1389MH
and the FLASH access time
whether is suitable or not.
Check connection lines
NO
between SDRAM(IC503) &
MT1389MH and the SDRAM
is damaged.
Check the related circuit of
NO
MT1389MH IC501 Pins138,
142, 144, 145.
NO
Check the load OPEN &
CLOSE switch.
NO
Check the Tray control IO pins
on MT1389MH.
NO
Check the Tray control MOTOR
& SERVO circuit IC400.