Reset Circuit - Casio PCR-255 Service Manual

A
A
Power ON 9.65 VAC 10.52V
Plug out 0
Voltage level is measured at the following condition.
1. Plug the power cord in AC outlet.
2. Mode switch position : REG, display 0.00
3. Put in the memory protection batteries.
4. Plug out : Plug out the power cord , the memory protection batteries in.

6-2. Reset circuit

RESET
B
B C D
5.76V 10.45V
0 0 0
VDD
S-80728AN
GND
Pin No.17
— 5 —
C
D
F
E F
0.78V 0.12V Pulse
0 4.13V
When the voltage level at the pin No.17 of CPU is
not stable, CPU does not work properly.
To make a stable voltage, the reset IC(S-80728AN)
is used for this circuit.
In case the voltage level of VDD becomes down
output terminof reset IC is out the stable voltage.
G
I
H
GND
E
G H I
5.07V -23.9V
0 4.30V 0