Hitachi RAM-18QH5E, Service Manual

Page: 61 / 78

– 67 –
LD304 b
links once
.
Comm
unication error
.
Is DC v
oltage of about 35V
being output to C
, D ter
minals?
(DC33v~38.5V is output nor
mally
.)
Ye
s
No
Interf
ace rela
y
Coil ter
minal
Contact ter
minal
Is v
oltage of about 35V being output
to both ends of R713?
Is DC 12V being applied to both ends of control side (coil ter
minals)
of interf
ace rela
y?
Is a v
oltage (10V or more) being
gener
ated between the contact
ter
minals of interf
ace rela
y?
Chec
k the interf
ace curcuit.
Ye
s
Ye
s
No
No
No
Ye
s
D707 and C710 could be def
ectiv
e
.
There ma
y be def
ectiv
e par
ts betw
een
12V output of s
witching po
w
er supply on
control P
.W
.B
. and interf
ace rela
y.
(Also
be care of solder-touch, etc.)
Repalce the interf
ace rela
y.
No
Ye
s
C
, D (Indoor 1)
C2, D2
(Indoor 2)
Which is
brok
en, C1, D1 (Indoor 1) or
C2, D2 (Indoor 2)
Switching po
w
er circuit f
or indoor 2
P
.W
.B
. could be def
ectiv
e
.