JCM J3500E Service Manual - page 11
9
G
D
S
Q8
2SK2569
R
CX
RX/CX
&
1
2
3
14
15
4
13
U16A
SN74LV123APW
S
2
D
6
D
7
S
3
G
4
S
1
D
5
D
8
Q9
IRF7424
D25
1SS226
R52
153
C69
104C
R57
472
1
2
3
U5A
SN74LV32APW
-
+
3
2
1
U19A
LM393M
R14
472
R60
103
R
CX
RX/CX
&
9
10
11
6
7
12
5
U16B
SN74LV123APW
R58
222
C28
101C
R53
473
9
10
8
U5C
SN74LV32APW
C61
35V 1000u
R54
103
C25
471C
R12
472
-
+
5
6
7
U19B
LM393M
12
13
11
U5D
SN74LV32APW
R51
103
R50
103
4
5
6
U5B
SN74LV32APW
C64
104F
C35
471C
R56
472
R49
103
C33
101C
R13
103
C23
471C
PRI_EN
PRSTB1
PRSTB2
TH
PR/LAT0
PRCLK0
PRDIO
nRESET
VCC
VCC
+24V
VCC
VCC
VCC
VCC
VCC
VCC
TH
TH
VH
28
VH
27
TM1
19
TM2
9
DO
24
GND
18
GND
17
GND
16
GND
15
VDD
8
/STB3
7
/LAT
22
CLK
23
/STB2
6
VH
4
VH
3
VH
26
VH
25
VH
2
VH
1
DI
5
NC
21
/STB1
20
GND
14
GND
13
GND
12
GND
11
GND
10
CN7
28FE
VCC
1
2
12
13
U17A
SN74LV10APW
PRSTB3
FB28
BLM21AG121SN1
FB31
BLM21AG121SN1
FB29
BLM21AG121SN1
C29
101C
4
5
6
U15B
SN74LV32APW
12
13
11
U15D
SN74LV32APW
1
2
3
U15A
SN74LV32APW
9
10
8
U15C
SN74LV32APW
FB26
BLM21AG121SN1
FB27
BLM21AG121SN1
FB32
BLM21AG121SN1
FB30
BLM21PG600SN1
C32
104C
C60
35V 1000u
C30
50V 10u
C27
50V 10u
C22
50V 10u
C24
50V 10u
4
5
6
3
U17B
SN74LV10APW
9
10
8
11
U17C
SN74LV10APW
3.2.5. printer drive circuit
Printer drive circuit consists of U11(MPU), U15,U16,U17 and U18 (driver), U19 (comparator)
Usually, P73 outputs “L” level. When one of department key is depressed, CPU outputs printer power
Signal “H”(PRI_EN) from output port P73 of U11. Q8and Q9 turn ON. Thus the thermal head
On the printer mechanism is activated.
Serial print data input from “PRDIO” is transferred to the shift register synchronously with the
Clock ”PR_CLK0”, then stored in the latch register at the timing of the latch ”PR/LAT0” signal.
The heat elements which correspond to the latched print data are activated while each gate is on.
The gates are on while each head activation signal (PRSTB1-PRSTB3) is low.
3.2.6. Comparator circuit
The thermal head has a thermistor for detect the head temperature.
The level of the “TH” is changed according to head temperature.
When head is heated too high temperature, the output level of comparator goes to “H” level.
Thus thermal head will be non-activity.
This status is released when the head become cool.