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Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with
each other.
Indoor P.W.B.
Outdoor P.W.B.
Terminal board
Terminal board
C
D
C2
D2
D101
I/F 0V
C821
R821
C822
0V
0V
0V
0V
5V
5V
5V
0V
0V
0V
5V
0V
0V
0V
0V
I/F 0V
0V
IF transmit
output (SDO)
Indoor 2
IF receive
input (SDI)
Micro
computer
5V
12V
5V
5V
HIC
5V
R813
R812
C802
Q803
C804
R811
R810
0V
L802
L812
C815
NF COIL
C813
C814
Interface
relay
35V
(Communications from indoor micro computer to outdoor micro computer)
(Communications from outdoor micro computer to indoor micro computer)
Fig. 2-1 Indoor / Outdoor interface Circuit 2
10
11
I/F 0V
+5V
+5V
+5V
+5V
+5V
+5V
+5V
+5V
+5V
R265
R268
R823
C828
R269
R270
R271
R272
R821
R844
R805
R266
R347
R346
C217
C218
C219
R264
C822
C821
R267
R822
R273
Q803
Q203
D212
D207
IC6
Q207
C316
Y0
X0
X1
X2
X3
X
A
B
INH
Y1
Y2
Y3
Y
IC15
0V
0V
0V
0V
0V
0V
0V
0V
0V
0V
0V
17
37
38
1
1
12
14
15
11
13
10
9
6
7
5
2
4
3
8
78
M
I
C
O
N
Summary of Contents for RAM-90QH5
Page 13: ... 12 ...
Page 14: ... 13 ...
Page 15: ... 14 ...
Page 19: ... 18 BASE DRAIN PIPE A DRAIN PIPE BUSH 100 mm ABOVE 10 11 ...
Page 21: ... 20 CONSTRUCTION AND DIMENSIONAL DIAGRAM MODEL RAM 90QH5 Service space ...
Page 26: ...CIRCUIT DIAGRAM MODEL RAM 90QH5 27 ...
Page 28: ... 31 ...
Page 31: ... 37 ...
Page 32: ... 39 ...
Page 33: ... 41 ...
Page 34: ... 43 ...
Page 36: ... 45 90 23 ...
Page 42: ... 51 REFRIGERATING CYCLE DIAGRAM MODEL RAM 90QH5 ...
Page 51: ... 60 3 System power Module Circuit ...
Page 60: ... 69 Electric expansion valve thermistor NARROW PIPE 5 5 5 5 8 8 8 ...
Page 72: ... 85 ...
Page 76: ... 90 Lighting mode self diagnosis lamp Location of self diagnosis lamp 1 RAM 90QH5 ...
Page 77: ... 91 Lighting mode self diagnosis lamp 2 RAM 90QH5 ...
Page 83: ...HITACHI PM NO 0371E Printed in Malaysia RAM 90QH5 ...