Checking The Second Step Of Servo (2); Checking The Output Of Audio Signal - LG DVD6054 Service Manual

9. Checking the second step of servo (2)

Let's look over the initial step of servo
1) when the tray is closed, first of all, it should be
checked whether there is disc or not on tray
2) DVD laser is turn on and the lense is moved. if
there is a disc on tray, RF signal will appear
3) next, it should be confirmed which disc is that.
CD or DVD.
M/D
ASSY
PMD03
LD-DVD
IC202
DSP

10. Checking the output of Audio signal

IC401 is called as Audio DAC, DAC means Digital-
Analog Convertor.
This IC receives digital signal from MPEG and con-
vert digital signal to analog signal, so we can hear
sound...
IC401 is connected with OP - AMP and an analog
Audio signal is amplified at the OP - A MP.
because the analog audio signal from DAC is a
very low level.
DAC_PCM_CLK
IC501
DAC_SCLK
DAC_LRCK
MPEG
DAC_PCMOUT
(STI5589)
DVD laser on
AUDIO
DAC
(PCM1742)
Analog
audio
IC402
OP-
AMP
3-6
4) the following step will be done continuously
DVD -Laser on -> move up/down in according to
disc type, there will be RF signal...
5) after confirming disc, CD or DVD laser turn on
and focus servo is executed...
the below picture is related signals when CD
disc is inserted
CD laser on
4)
DAC_PCM_CLK : this is the system clock for
IC401
DAC_SCLK : this is standard clock to synchronize
the audio serial data
DAC_LRCK : R-chanel and L-chanel are selected
among the audio serial data by this
DAC_PCMOUT3 : serial audio data
PI
CD/DVD
LD-CD
LD-DVD
DA_XCK
DA_BCK
DA_LRCK
DA_DATA