Section Two Unit Circuit Principle
3.2.1 Introduction to laser head
Function introduction to laser head flat cable is shown as the following table:
- 79 -
Pin
Name
Signal flow direction
DVD disc
CD disc
No disc
Function description
1
F-
Input loader
2.52
2.34
0.46
2
F+
Input loader
2.49
2.49
0.93
3
T+
Input loader
2.53
2.51
0.94
4
T-
Input loader
2.58
2.51
0.93
5
C
Input MT1389
2.2
2.25
2.04
Disc data signal
6
D
Input MT1389
2.2
3.2
2.04
Disc data signal
7
IOA
Input MT1389
0.01
3.2
3.21
Disc identification signal, CD is 3.3V, DVD is 0V
8
RF
Input MT1389
2.21
2.53
1.28
The sum of disc data signal
9
A
Input MT1389
2.17
2.22
2.04
Disc data signal
10
B
Input MT1389
2.19
2.27
2.04
Disc data signal
11
F
Input MT1389
2.07
2.44
2.03
Supplementary signal used in trace
12
GND
Ground
0.01
0.01
0
Grounding
13
V20
Input loader
2.04
2.06
2.03
Reference voltage
14
Vcc
Input loader
5.04
5.04
5.02
Supply voltage for loader
15
E
Input MT1389
2.06
2.45
2.03
Disc data signal
16
Blanking
haning in air
0.01
0
0
unused
17
VR-CD
Input loader
0.21
0.01
0
Through the handling inside loader, make sure
MD11 is 180mV when reading CD
18
VR-DVD
Input loader
0.01
0.2
0
Through the handling inside loader, make sure
MD11 is 180mV when reading DVD
19
LD-CD
Input loader
0.09
2.1
0
CD laser power control signal
20
MDII
Input MT1389
0.21
0.2
0
CD and DVD laser power monitoring signal
Focus error signal is added to two sides of pick -
up focus coil
Trace error signal is added to two sides of pick-up
trace coil