Samsung Electronics
4-6 PCB Inspection Method
4-6-1 Pre-inspection Notices
1. Turn off the breaker, AC power source, before disassembling the unit because of electrical hazard.
2. Confirm the complete discharge of capacitor C102, C702, C703, C704, C705, C706, C707 on the INVERTER PCB when you touch the
PCB.Especially dischargeing speed of C702-C707 is very slow because of little load in stand-by condition. To confirm the voltae of
C702-C707, measure the DC link voltage at the IGBT module pins near C701 at which applying voltage(450-510Vdc) is marked.
To confirm discharging of C102, measure the voltage of non mounted C103 solder hole or check if all LEDs are off.
3. Don’t touch the metal body of electrolytic capacitor for avoiding electrical shock before confirming discharge.
4. To discharging the capacitor use power resistor of about 1 Kohm 10W. Soldering tool(non electronic temperature control type) can
be used as a discharging resistor.
5. Don’t pull the lead wire but hold the whole housing to disconnect or connect a housing from or to the PCB.
4-6-2 Inspection Procedure
1. Check the connection of each housing to the connector first and the peeling of PCB copper pattern.
2. The PCB is composed of the 3 part in the indoor unit.
1. ●I
NDOOR Main PCB part : Indoor unit control, MICOM and surrounding circuit, relay, fan motor driving circuit,
sensor reading circuit, buzzer driving circuit and DC power supplying circuit.
1. ●D
isplay PCB part : LED lamps, Switch,Remocon module.
1. ●I
NDOOR EMI PCB part : Line filter, Noise Capacitor and Varistor
3. The PCB is composed of the 3 part in the outdoor unit.
1. ●E
MI PCB part : Line filter for electrical noise, Varistors for surge and Fuses.
1. ●M
AIN PCB part : Refrigeration cycle controller with MICOM
1. ●I
NVERTER PCB part : Compressor driving inverter and BLDC fan controller
4-6-3 Indoor Detailed Inspection Procedure
No Procedure Inspection Method Cause
1
Open the electronic
component box and
check the PCB fuse
Turn off the power
1) Is the Fuse F701 on the EMI PCB blown?
2) Is the Fuse F702 on the MAIN PCB blown?
• Over current
• Indoor fan motor short
• PCB AC Part pattern short
2
C
heck the LEDs for
DC power and communi-
c
ation condition
Turn on the power
1) Is RED LED blinking?
1) his led means micom is running normally.
2
) Is GREEN LED blinking?
1) This means communication between Indoor and
Outdoor unit is on
3) Is YELLOW LED blinking?
1) This means communication between Indoor and
w
ired remote controller is on.
1) It may take one minute to start communication
• Communication ciucuit trouble
• Communication wire connection trouble
• wrong connection for power supply wire of
remote controller
3
C
heck the DIP and rotary
switch on the PCB
1) Is the setting of each switch proper?
• Wrong setting of switch
4
C
heck the DC voltage 1) Is the voltage of CN32 pin #1-#2 12V?
2) Is the voltage of C109 V?
• SMPS on MAIN PBA trouble
• Load short
5
F
AN operation checking
Press the ON/OFF button.
1. FAN Speed[HIGH]
2. FAN mode
1) Is the FAN motor running?
2) Is the connection of CN73 normal?
• Controller trouble inside of the fan motor
• connector trouble of CN73
4-33
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