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Machine to realize disc in/out function. The working process of disc in/out circuit is shown as follows:
O U T d i s c : V C C - Q 1 2 7 C E e l e c t r o d e o n - L O A D + - E l e c t r i c m a c h i n e - L O A D -
-Q130CE electrode on-R197-Ground.
When not opening disc tray, pin 39 and 54 of U201 (MT1389) are low level. When opening disc tray,
pin39 of U201 (MT1389) sends a high level; Q130 is on; Q130 collector electrode changes into low
level; LOAD- changes into low level; Q127 base electrode changes into low level; Q127 is on. Q127
collector electrode changes into high level and LOAD+ changes into high level.
IN disc: VCC-Q128CE electrode on-LOAD- -Electric machine-LOAD+ -Q129CE electrode on-R197-
Ground
When closing disc tray, pin 54 of U201 (MT1389) sends a high level; Q129 is on; collector electrode
changes into low level; LOAD+ is low level; base electrode through R230 and Q128 is low level; Q128 is
on; Q128 collector electrode changes into high level; LOAD- changes into high level.
The function of Q180 is interlock IN DISC and OUT DISC signal to ensure the two are not high level
at the same time. When the two are high level input, base electrode of Q130 is made to low level through
Q180 on to ensure the normal working of disc in/out circuit. The function of electrolytic capacitor CE168
and TC307 is to avoid the sudden change of the voltage on two ends of disc in/out electric machine to
make disc in/out acts smooth.
3. Key point voltage (unit: V) is shown as the following table:
Base electrode B
Collector C
Emittor E
Base electrode B
Collector C
Emittor E
Read disc
5.06
5
5.06
5.01
5.03
5.06
Open disc tray to
proper position
4.79
4.77
5.06
4.77
4.79
5.06
Open disc tray
4.74
5.05
4.74
4.76
0.2
4.76
5.06
4.76
4.33
4.76 4.76
5.02
4.76
5.06
Close disc tray
4.74
4.33
4.74
4.76
5.05
4.76
5.06
4.76
5.03
4.76
4.79
0.2
4.79
5.06
Base electrode B
Collector C
Emittor E
Base electrode B
Collector C
Emittor E
Read disc
0
5
0
0
5.03
0
Open disc tray to
proper position
0
4.77
0
0
4.79
0
Open disc tray
0
0.93
0
4.76
0.2
4.76
0
0
4.79
5.02
4.79
0
Close disc tray
0
4.76
5.05
4.76
0
0
0.93
0
4.79
0.2
4.79
0
Base electrode B
Collector C
Emittor E
Read disc
0
0
0
0
0
OUT
IN
State
State
State
Q130
Q128
Q127
Q129
Q180