4-4 PCB Inspection Method
4-4-1 Pre-inspection Notices
1. Check if you pulled out the AC power plug when you eliminate the PCB or front panel.
. Don’t hold the PCB side not impose excessive force on it to eliminate the PCB.
3. Don’t pull the lead wire but hold the whole housing to connect or disconnect a connector to the PCB.
4-4-2 Inspection Procedure
1. Check connector connection and peeling of PCB or bronze coating pattern when you think the PCB is broken.
. The PCB is composed of the parts.
1.
Indoor Main PCB Part : MICOM and surrounding circuit, relay, room fan motor driving circuit and control circuit, sensor driving
circuit, power circuit of DC1V and DC5V, and buzzer driving circuit.
1.
Display part : LED lamp, Switch, Remocon module
4-4-3 Indoor Detailed Inspection Procedure
No
Procedure
Inspection Method
Cause
1
Plug out and pull the PCB
out of the electronic box.
Check the PCB fuse.
1) Is the fuse disconnected?
•
Over current
•
Indoor Fan Motor Short
•
AC Part Pattern Short of the MAIN PCB
2
Supply power.
If the operating lamp
twinkles at this time,
the above 1)~3) have
no relation.
Checking the power voltage.
1) Is the BD71 input voltage AC00V~AC40V?
•
Power Cord is fault, Fuse open. Wrong Power
Cable Wiring, AC Part is faulty.
) Is the voltage between both terminals of the
C109 on the side of the transformer DC1V ±0.5V?
•
Switching Trans or Power Circuit is faulty
3) Is the voltage between both terminals of OUT
and GND of IC0(KA7805) DC5V ±0.5V?
•
Power Circuit is faulty, Load Short
3
Press the ON/OFF button.
Checking the power voltage.
1) Is the voltage over AC180V being imposed on
1)
terminal #3 and #5 of the fan motor
connector(CN7)?
•
Fan Motor of the indoor is faulty
) Check the voltage of both terminals of
terminal block 1 and N(1) after 3 minute
operation.: AC0V
•
Relay(RY71) Contact is faulty
4
Press the ON/OFF button.
1. FAN Speed [High]
. Continuous Operation
1) Is the voltage over AC180V being imposed on
1)
terminal #3 and #5 of the fan motor
connector(CN7)?
•
Fan Motor of the indoor is faulty
) The fan motor of the indoor unit doesn’t run.
•
Fan Motor Connector(CN7) is faulty
3) The power voltage between terminal #3 and #5
of the connector(CN7) is 0V.
•
ASS’Y Main PCB is faulty
•
Connection is faulty
Samsung Electronics
4-11