LG DV7511E6S, Service Manual

Page: 13 / 57

3-4
Pick-Up
TACT
A/B/C/D
Reference
2.1V
Reference
2.7V
IC201
DSP
(MN103S)
IC201
Motor
Drive
We can see how the reference voltage,
mentioned previous page, will work on servo
control..
1) The DC level of RF signal from P/up is 2.1V
2) The DC level of TE and FE is 1.65V
3) Correct DC level of these signal make servo
work normally.
Even though, the reference voltage come out
correctly from DSP,
If A/B/C/D are not biased by 2.1V, and checking
the P/up is needed.
If the DC level of TE is not 1.65V, check DSP
and replace it…
In case of FE, procedure is same
FE
1.65V
TE
A/B/C/D
1.65V
2.1V
5. Reference Voltage 2
CLOSE
-SW
LIMIT
-SW
PMD01 PMD02
FM+
LD-CD
Q203
IC202
DSP
M/D
ASSY
IC201
Motor
Drive
PMD03
Let’s look over the initial action of M/D...
1) When the tray is closed, CLOSE-SW should
be changed from 5V to 0V and DSP need to
detect this change
2) Feeding Motor move the P/up to inner area until
the LIMIT SW is detected
3) After DSP detect the LIMIT SW, DVD laser is
turned on and go to the next step
4) if there is a DISC on the tray, the RF will be
detected by the DVD laser and go to next step..
Check the CLOSE-SW and LIMIT-SW
if anything of the both is not detected, the next
step won’t go on. This means that even though
there is a DISC on the tray the DISC will not
rotate.
FM+
CLOSE-SW
P/up move
to inner area
Limit sw
detect
DVD LD on
Tray close
LIMIT-SW
DVD-LD
6. Checking the initial step of M/D Ass’y