Hitachi RAD-25NH7 Service Manual page 48

6. Initial Setting Circuit (IC401)
When power is supplied, the microcomputer reads the data in IC401 (E
G
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; data will not be erased even when power is turned off.
G
1
2
3
4
2
IC401 (E PROM)
0V
7. Temporary Switch
INDICATION P.W.B.
5V
Temporary
Switch 1
Temporary Switch 2
The temporary switch is used to operate the air conditioner temporarily when the wireless remote control
G
is lost or faulty.
5V
8
C401
7
0V 0V
6
5
Option
5V
C1 1
C2 2
M1
3
M2 4
CN9
CN11A
7
5V 5V
Fig. 6-1
R601
R701
C601
R602
0V
Fig. 7-1
– 58 –
2
PROM) and sets the preheating
Microcomputer
27
SCL
}
External ROM
26 SDA
Micro computer
48 HA input
HA output
33
0V