Initial Setting Circuit (Ic401) - Hitachi RAK-25NH4 Service Manual

7. Initial Setting Circuit (IC401)

When power is supplied, the microcomputer reads the data in IC401 or IC402 (E
preheating activation value and the rating and maximum speed of the compressor, etc. to their initial
values.
Data of self-diagnosis mode is stored in IC401 or IC402; data will not be erased even when power is
turned off.
1
2
3
4
IC401 or IC402 (E
0V
5V
8
C401
7
0V 0V
6
5
2
PROM)
5V 5V
Fig. 7-1
– 66 –
2
PROM) and sets the
Microcomputer
27 SCL
}
External ROM
26 SDA