Samsung MH18ZC1(C2)-09 Service Manual page 31

Troubleshooting
5-4-2 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 "ting" 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
Is the operation lamp
Y
of indoor unit on when
No trouble
the operation /stop but-
(normal)
ton of remote controller
Is the communication
N
Check of remote signal of remote con-
controller
troller surely sent and
Is there no problem
Y
between the connector
Normal
of Ass'y display PCB and
the receiving module?
Replace of Ass'y dis-
5-8
Y
Is the operation lamp flickering with the
is pressed?
N
Is the outdoor power connected normally?
received ?
Y
Is the fuse (F701, 250V, 3.15A) of PCB open?
N
play PCB
Is the voltage at Socondary side of trans-
former of PCB (TN71)? (AC15V~AC25V)
Is the output voltage of voltage regulator
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
Apply the power
sound of "ting"?
N
Y
N
Y
IC (KA 7812) DC 10V and 12V?
Y
Y
N
Check of the installation method
and electrical circuit
Y
Replace the fuse (250V, 3.15 A).
N
Transformer is out of order -
replace
Repair and replace the power
N
source rectifying diode (D101-
D105) and KA7812.
N
KA7805 is out of order - replace
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