Hitachi RAS-25WX8 Manuel De Maintenance page 116

6-2. Reset Circuit
The reset circuit initializes the microcomputer program when Power is "ON" from "OFF"
Low voltage at pin
Fig. 6-7 shows the reset circuit and Fig. 6-8 shows waveform at each point when power is turned on and
off.
When power is turned on, 12V line and 5V line voltages rise and 12V line voltage reaches 10.9V an
reset voltage input to pin
Reset voltage will be hold "Hi" until the 12V line voltage drops to 9.90V even though the power shuts
down.
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MAIN P.W.B.
12V
R287
R284
0V
0V
0V 0V
resets the microcomputer, and HI activates the microcomputer
48
of microcomputer is set to Hi.
48
10.9V
6
0
6
0
manuals search engine
5V
D208
8
0V
-
2
1
R252
+
3
IC5(1/2)
R288
Fig. 6-7
12V line
5V line
Reset voltage
12V line
5V line
Reset voltage
Fig. 6-8
– 115 –
Microcomputer
56
RESET OUT.
48
RESET
0V
Time
9.9V
Time