Panasonic FA-A888 Service Manual ▷ View online
4-15
Electrical
4) Original feed motor clock sensor ( KM CLK )
The original feed motor clock sensor consists of a photointerruptor and timing
plate (for monitoring motor rotation) and output of this sensor is input to the
CPU via a noise filter which consists of resistors and capacitors.
6
5
4
VL
KM CLK
GND
R38
CN2
4.7k
+5V
GND
R14
10k
C33
1000p
1000p
GND
TP12
74
IC13
INTP2
CN2
7
9
9
VL
+5V
REGS DA
8
CN2
REGS
Q8
2SC2712
2
3
1
AN+24V
R66
10k
R48
100k
27 5
6
IC1.2
TP13
R24
100
100
GND
C34
100pF
+5V
TP8
R17
10k
9
8
14
IC3.3
22k
R18
PGND
PGND
R28
2k
C8
0.1
R15
10k
R34
9.1k
68
ANO1
IC13
73
INPT1
56 ANI0
SD007
SD020
5) Registration sensor ( REGS ) / Timing sensor ( TIMS )
The registration sensor and timing sensor is a reflection type of photointerruptor
which consists of an LED and phototransistor. The phototransistor detects the
reflection of infrared light from the LED for detecting the original.
The cathode terminal of the LED is connected to a voltage-current converting
circuit and D-A output ( Analog voltage output ) from the CPU controls the input
current for the LED. In addition, the photocurrent of the phototransistor is
converted to a voltage value by resistors. They are connected to the input
terminal of the sensor, to the input comparator circuit via a noise filter for
comparing to the reference voltage ( Aprrox. +2V ). When the output voltage
from the sensor is higher than reference voltage, the output signal from the
comparator circuit becomes Low, and transfers to the CPU as no original
detection.
The CPU controls the input current for the LED ( brightness of LED ) to maintain
proper sensor output voltage.
4-16
6) Original exit / reverse sensor ( HANS )
The original exit/reverse sensor is a reflection type of photointerruptor which
consists of an LED and phototransistor. The phototransistor detects the reflection
of infrared light from the LED for detecting the original.
The sensor input voltage is divided 1/3 by R87 and R88 and inputs to the A-D
converter. Then PWM signal which is a corresponding output from the A-D
converter, is output from the gatearray ( IC14 ). This PWM signal is converted
to analog voltage by an integrating circuit ( R2, C12 ) and is amplified 2 times
by a non-inverting amplifier to be a reference voltage for the comparator.
The reference voltage for the comparater is 2/3 of the high level of each sensor
output.
Also,during a no original detecting condition, the input voltage to the CPU is
less than 1V, pin 49 of CPU becomes high to increase brightness of the LED.
RDDPWM
(IC14-18)
R2
10k C12
0.1
R52
22k
22k
PGND
1 AN+24V
2 HANS
2 HANS
3RDDLED
C11 0.1
R51
22k
2
3
1
IC1.1
R35
10k
C9
0.1
PGND
R4
10k
IC3.1
4
5
5
2
R47 100k
+5V
R24
10k
TPS
+5V
D1
R3
10k
AN+24V
TP1
R90
2.2k
2.2k
R89
3.3k
PGND
PGND
2
3
DT
1
R87
3k
R88
1.5k
PGND
C29
0.1
CN7
IC13
75
58
49
INTP3
ANI2
P12
SD008
4-17
Electrical
IC6
+5V
+5V
5
7
6
4
C42
0.33
C6
0.1
GND
R53
22k
D4
+5V
R95
10k
2
3
1
DT
GND
IC13
7 RESET
IC14
C19
0.1
GND
GND
C3
0.1
36
RES1
37
WDT
RES2
39
(3) Reset circuit
This circuit resets the CPU and output reset signal for the gate array.
When the DC 5V line drops to less than 4.3V (or immediately after the power is
turns ON) the output of IC6 is set to a low level. ( After power is turned ON and
the DC 5V line is higher than 4.3V, the reset is maintained for a while.) Also,
this circuit is a timer which is monitoring the CPU status to avoid abnormal
operation.
7) ADF open/close detecting switch,original feed cover open/close detecting switch,
original exit cover open/close switch( AUOD,FGOD,TGOD )input circuit.
This circuit is the input circuit for the ADF open/close detecting switch, original
feed cover open/close detecting switch, and exit cover open/close detecting
switch. When one of these switches are in the OFF condition, the power ( DC
24V ) to all motors and solenoids is cut. The 24V ON/OFF signal is input to a
zener diode which reduces the voltage to DC 17.2V, and this lower voltage is
input to the base terminal of the transistor to convert a DC5V signal. The DC
5V signal is, then input to the CPU.
IC14
55
56
57
P2
P3
P4
+5V
+5V
3
2
1
DT
R33 10k
ZD9
R13
10k
2
3
DT
1
ZD10
+5V
R25
10k
2
3
1
DT
ZD2
CN6
2
1
TGOD
FD+24V
DC+24V
CN4
3
8
8
7
6
5
NC
Vp
AUOD
ADF+24V
FGOD
SD009
SD010
4-18
(4) Drive circuit
1) Original feed motor( DFM ) drive circuit
This circuit controls the forward and reverse movement of the original motor
which is a gatearray ( IC14 ), hybrid IC ( IC15 )and other components.
The CPU outputs the control signal ( 2 bits control signal ) to the gatearray
through a data bus for operating the original feed motor. The gatearray outputs
the original feed motor control signal from pin 65~68. Pin 65 and 66 of the
gatearray output the PWM signal for controlling the original feed motor speed.
( Forward rotation : pin 65 / Reverse rotation : pin 66 )
IC15 is a hybrid IC which is 4 elements of power MOSFET, and input control
signals from pin 65~68 from the gatearray is output for driving the original feed
motor.
The original feed motor is driven the combination of control signals
which are output from pin 65~68 of gatearray ( IC14 ).
Pin No.
OFF
OFF
Rotate registration roller
Rotate pick-up/original
feed roller
Brake
feed roller
Brake
65
0
0
Pulse control
signal
0
66
0
Pulse control
signal
0
0
67
0
1
0
1
68
0
0
1
1
IC14
67
14
65
12
68
15
66
3
72
1
M1H1
M1L1
M1H2
M1L2
M1H2
M1L2
CHGCLK
IC15
+5V
INA
INB
INC
IND
IND
CLK
13
16
VCC2
SG
C18
0.1
OUT1-1
10
11
11
6
7
2
9
9
8
OUT1-2
OUT2-1
OUT2-2
OUT2-1
OUT2-2
VZ
VCC1-1
VCC1-2
L2
L1
CN4
DFM1
DFM2
1
2
C47
1
+24V
C5
0.1
0.1
PGND
GND
0.1
SD011
Click on the first or last page to see other FA-A888 service manuals if exist.