Sharp ER-A450 Service Manual page 25

Receipt feed motor: The motor rotates counterclockwise.
Step No.
A
1 ON
2 ON
3 OFF
4 OFF
Journal feed motor: The motor rotates clockwise.
Step No.
A
1 ON
2 ON
3 OFF
4 OFF
Note 1: ON = Conducting
OFF = Not conducting
Note 2: Step No. is performed by the internal process of TPRC1.
·
When the motor is locked, the circuit is connected to the CPU
through MPCA6.
3) Print circuit
STRB1~STRB5
LATCH
SO
TPRC 1
PB
SI
RAM
CLOCK
VHCOM
VRES
8. Drawer drive circuit
VRESC
51 DR0
52 DR1
CPU
TD62308F
50
DOSP
R163
C105
47K
1000P
The drawer is directly supported by the CPU. No action starts when
the power supply is not steady as the output stage of the driver is
pulled VP by VRESC signal.
Drawer open and close is sensed with the microswitch provided in the
drawer whose signal is level converted with R161 and R162 and di-
rectly read by the CPU.
Phase
B C
OFF ON
OFF OFF
ON OFF
ON ON
Phase
B C
OFF OFF
OFF ON
ON ON
ON OFF
Thermal
printer
head
VH
+24V
+24V +24V
DRAW0
IC9
DRAW1
R161 22K
R162
4.7K
Fig. 8-1
9. Key, display, time buzzer controls
D
MPCA7
OFF
ON HTS1
STH1
ON
SCK1
OFF
RESET
INT2
POFF
D
ON
CPU
P11
OFF
P10
OFF
P12
RES
ON
RES0
ST0~ST7
KR0~KR7
KR10,KR11
Key board
G1~G10
a~g,DP
Display
VCC
1) Power on sequence
During service interruption, the CKDC8 senses POF within 500msec.
When service interruption is cancelled by turning on the power, the
CKDC8 cancels resetting of the CPU in the command mode. After
initializing each port, the CPU reads the start condition (1 byte).
POF
Drawer
RES1
solenoid
SHEN
LDRQ
After sampling POF High, the CKDC8 performs mode scan and key
scan at 1 , then cancels resetting of the CPU. After being cancelled,
the CPU initializes each port at 2 and reads the start condition.
After being cancelled, the CPU reads the start condition without fail to
set the sift mode. If, however, the first starting is made in other than
SRV mode after the CKDC8 resets the CPU without request from the
CPU, the CKDC8 sets the start condition supposing that starting is
made in SRV mode.
4 – 18
HTS
STH
SCK
RESET
LDRQ
ERC
SHEN
P-OFF
VDD
RES0
Driver
Driver
2
B
BUZZER
Fig. 9-1
1 2 Start condition
Fig. 9-2
HTS
STH
SCK
RES1
LDRQ
ECR
SHEN
POFF
RESET
ST0~ST7
KR0~7,KR10,KR11
T0~T9
a~g,DP
CKDC 8
Next command