Serial Signal Diagnosis - Fujitsu AS*9LSACW Service Instructions Manual

Serial Signal Diagnosis

[Check Point] Check and find out if the cause is at Indoor unit or Outdoor unit.
* Remove the side cover of Outdoor unit for testing the Outdoor unit connection terminals with a meter.
* Turn on the power and press [TEST] button of Remote control.
[Checking Flow Chart]
CAUTION: Do not touch the terminals or electrical components to avoid electric shock.
[Check Indoor Unit]
Is AC220V/AC230V applied to the terminals N-L on
the Outdoor unit terminal plate?
Measure the voltage between terminals N-3 on the
Outdoor unit terminal plate.
Refer to Fig.1 for Measuring Method.
Judge the result based on Table 1.
Outdoor unit terminal
plate
3
Red
L
Black
Power supply
AC220V/230V
N
White
Table 1: Judgement table
Measurement 1
voltage value
0 5V
30 60V
YES
Measurement method 1
Serial
Black
signals
White
Measurement method 2
Black
White
Fig.1 Selial Signal Measuring Method
Measurement 2 Indoor unit
voltage value trouble display
30 60 V
0 5V
NO
3
Red
L
N
3
Red
L
N
Outdoor unit
operation
Display No operation
Display No operation
07-08
Connecting cable wiring defect
In correct wiring
Main PCB defective
Diode
(Dielectric voltage : Higher than 600V)
+
-
(Normal : DC30
+
-
(Normal : DC30
Defective point
Indoor unit control PCB defective
Outdoor unit fuse open (input)
Inverter defective
Range DC
60V)
Range DC
60V)