Hitachi RAF-25NH5 Instructions De Service page 306

nspection method 4
heck the number of times LD303 blinks.
ommunications abnormally between microcomputers.
LD303A blinks
LD303A blinks once
External microcomputer
A Ð internal unit 1
communications error.
LD303A blinks twice
External microcomputer
A Ð internal unit 2
communications error.
LD303A blinks three
times *2
External microcomputer
A Ð internal units 1 and
2 communications error.
heck the internal P.W.B.
connected to the internal
unit in question. *1
The internal control P.W.B. is broken.
Replace the internal P.W.B.
LD303A blinks nine times
External microcomputer A Ð
external microcomputer B
communications error
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heck the internal P.W.B. connected
to the internal unit in question. *1
abnormally
The internal control
P.W.B. is broken.
Replace the internal
control P.W.B.
heck to see that 1-D1
and 2-D2 are not
connected in reverse.
32-37V
Normal
Measure the voltage
of the 1-D1 and
2-D2 terminal board.
Turn off the power source, and remove
the connecting cord of 1-D1 and 2-
D2. Then reconnect the power source,
and measure the voltage of the external
terminal board 1-D1 and 2-D2.
heck the switch power
source P.W.B. of the
external unit. *3
heck the external
unit control P.W.B.
Normal
abnormally
The external unit control P.W.B. is
broken. Replace the control P.W.B.
- 342 -
Normal
The external control
P.W.B. is broken.
Replace the external
control P.W.B.
Treat 1-D1 and 2-D2
as 3-D3, and check.
Normal
abnormally
The internal P.W.B.
32-37V
is broken. Reconnect
Normal
once of the internal
units, and replace
whichever of the
control P.W.B.s is
broken.
abnormally
The switch power
abnormally
source P.W.B. of the
external unit is
broken. Replace the
switch power source
P.W.B.
Normal
abnormally
The external unit
control P.W.B. is
broken. Replace the
control P.W.B.
LD303B blinks
LD303B blinks once
External microcomputer
A Ð internal unit 3
communications error.
LD303B blinks nine times
External microcomputer B Ð
external microcomputer A
communications error.