8
3-2 Fault Diagnosis by Symptom
3-2-1 When the power voltage is not available
1) Inspection items
(1) Is the power voltage is normal? (the rating voltage ±10% range)
(2) Is the power cord is correctly connected and is the contact good?
(3) Does the sound ÒtingÓ come out with the operation lamp (green) flickering when the power is
applied?
If it is not flickering, do inspect and repair in accordance with the following inspection
sequence.
2) Inspection sequence
Apply the power
Is the operation lamp of
indoor unit on when the
operation /stop button of
remote controller is
pressed?
Is the communication sig-
nal of remote controller
surely sent and received ?
Is there no problem
between the connector
of AssÕy display PCB and
the receiving module?
Replace of Ass'y display
PCB
Is the fuse (F701, 250V, 3.15A) of PCB open?
Is the voltage at Socondery side of transformer
of PCB (TN71)? (AC15V~AC25V)
Is the output voltage of voltage regulator IC
(KA 7812) DC 10V and 12V?
Is the output voltage of electrostatic voltage
regulator IC (KA 7805) DC 4.5 V - 5.5 V?
Replace the main PCB of indoor unit
Repair and replace the power source
rectifying diode (D101- D105) and
KA7812.
KA7805 is out of order - replace
Transformer is out of order - replace
Replace the fuse (250V, 3.15 A).
Is the outdoor power connected normally?
Check of the installation method and
electrical circuit
No trouble
(normal)
Check of remote
controller
Normal
Is the operation lamp flickering with the
sound of ÒtingÓ?
Y Y
N
N
Y
N
N
Y
N
Y
Y
Y
N
N
N
Y
N
Y
9-31043a(5)-TS 4/17/01 2:19 PM Page 8
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