Sharp AL-1215 Service Manual page 102

PIN
Signal Name IN/OUT
No.
235 cpudata10 IN/OUT CPU
236 VCC(AC) 3.3V Power
237 cpudata9 IN/OUT CPU
238 cpudata8 IN/OUT CPU
239 GND(CORE/DC) Power
240 cpudata7 IN/OUT CPU
241 cpudata6 IN/OUT CPU
242 cpudata5 IN/OUT CPU
243 cpudata4 IN/OUT CPU
244 VCC(CORE/DC) Power
3.3V
245 cpudata3 IN/OUT CPU
246 cpudata2 IN/OUT CPU
247 cpudata1 IN/OUT CPU
248 cpudata0 IN/OUT CPU
249 VCC(AC) 3.3V Power
250 xcpucs IN
251 mem_intr
252 GND(AC) Power
253 arb_intr OUT
254 cpusync OUT
255 cpu_ad9 IN
256 cpu_ad8 IN
(4) Heater lamp control circuit
a. Outline
The heater lamp control circuit detects the heat roller surface tempera-
ture and converts in into a voltage level. The converted voltage is
inputted to the CPU analog input pin.
R154
1kF
R158
10kF
D102
3
DA204K
or KDS226
(9-C2) RTH_IN
t
Thermistor
Heat Roller
The lower the heat roller surface temperature is, the greater the ther-
mistor resistance is, and vise versa.
Therefore, the lower the heat roller surface temperature is, the higher
the thermistor terminal voltage is, and vise versa. The thermistor termi-
nal voltage is inputted to the CPU analog port.
The CPU controls ON/OFF of the heater lamp by this input voltage
level.
Connected
Description
to
CPU data bus
CPU data bus
CPU data bus
CPU data bus
CPU data bus
CPU data bus
CPU data bus
CPU data bus
CPU data bus
CPU data bus
CPU data bus
CPU CS signal
(Not used)
CPU INTR signal
CPU CPU SYNC signal
CPU CPU address bus
CPU CPU address bus
VCC3 12V VCC3
R155 R156 R157
1MF 7.5kF 1kJ
IC120A
3
D101 +
1
2
-
NJM2903
MA700
12V
R159
or KIA393F
4.3kF
C196
0.1u
VCC3
2
3
12V
1
or KDS226
R169
IC122A
3 300J
+
1
2
-
LM358
12V
C197
or KIA358F
22000p
C199
0.1u
VCC3 12V 5V
R171 R172
1.2kF 10kJ
IC120B
5
+
7
6
-
NJM2903
or KIA393F C200
R173
10kF
22000p
AL-1551CS ELECTRICAL SECTION 12 - 8
(3) Reset circuit
This circuit detects ON/OFF of power to control start/stop of each cir-
cuit. The 3.3V voltage of the main PWB is detected by the reset IC to
generate the reset signal.
When the power voltage reaches the specified level, the circuit opera-
tions are started. Before the power voltage falls below the specified
level, the circuit operations are stopped to prevent against malfunc-
tions.
CPU
P34
/RES
VCC3
R114
11kF IC104
1
NC NC
2
IN VCC
3
NC OUT
4
GND Cd
R117
M51957BFP
10kF
The CPU converts the inputted analog voltage into a digital signal level
and compares it with the set value of the simulation to control on/off the
heater lamp according to the level, maintaining the heat roller surface
temperature at a constant level.
FTH (5-B2)
IC205
1
I1 O1
2
I2 O2
3
I3 O3
4
I4 O4
5
(3-3B) HL I5 O5
6
HT EMP I6 O6
7
I7 O7
8
VCC3 COM NC
D103 TD62503F
2
1
DA204K
R170
100J
RTH (1-A3)
C198
0.1u
THOPEN (4-A3)
[High temperature protect circuit in case of CPU hung up]
For IC120 3pin (reference voltage), +3.3V is divided by the resistor.
The thermistor terminal voltage is inputted to IC120 2pin.
When, the voltage at 2pin becomes lower than the voltage at 3pin
(when the heat roller temperature is about 220 – 230° C), IC120 1pin
becomes HIGH, and the HL signal is lowered to the GND potential
through IC124, stopping generation of the heater lamp ON signal.
(IC120 1pin is normal LOW.)
Reset _OUT (ASIC Reset)
VCC3
R115
10kJ
8
7
6
5
C124 C125
0.1u 22000p
SW5V
D103
1SS133
GND
Q205
DTA143XKA
IN
OUT
16
15
14
13
12 /HL
11
10
9
To AC circuit
(Heater lamp
Control)
CPU
AN0
ASIC
HLOUT (10-3A)