Pcb Inspection Method - Samsung SH09AI8R Service Manual

6-4 PCB Inspection Method

6-4-1 Pre-inspection Notices
1. Check if you pulled out the AC power plug when you eliminate the PCB or front panel.
2. Don't hold the PCB side not to 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.
6-4-2 Inspection Procedure
1. Check connector connection and peeling of PCB or bronze coating pattern before you think the PCB is broken.
2. The PCB is composed of the 3 parts.
• Main PCB Part : MICOM and surrounding circuit, relay, room fan motor driving circuit and control circuit, sensor driving circuit,
power circuit of DC12V and DC5V, and buzzer driving circuit
• Display part : LED lamp
• Switch part : Switch
6-4-3. Detailed Inspection Procedure
NO Procedure
Plug out and pull the PCB
1
out of the electronic box.
Check the PCB fuse.
2
supply power.
If the standard lamp
twinkles at this time, the
above 1) ~ 3) have no
relation.
Press the OPER/STOP
3
button one time to enter
the TURBO mode.
But, exclude the
RESERVE operation.
4
Press the OPER/STOP
button one time to enter
the OPER mode.
1. Air Volume[High]
2. Continuous Operation
Samsung Electronics
Inspection Method
1) Is the fuse disconnected? (F701)
Checking the power voltage.
1) Is the BD71input voltage AC198V~AC242V?
2) Is the voltage between both terminals of the output
C104 on the 2 nd side of the transformer AC12V
±0.5V?
3) Is the voltage between both terminals of OUT and
GND of IC02(KA78L05) DC5V ±0.5V?
Checking the power voltage.
1) Check the voltage of the relay(RY71) coil(IC05 PIN
#10 and GND : OV, PIN#7 and GND : 5V) during
operation(3 minutes after TURBO operation).
2) Check the voltage of both terminals of
terminal block 1 and N(1) after 3 minute
operation.: AC220V
1) Is the voltage over AC180V being imposed on ter-
minal #3 and #5 of the room fan motor
connector(CN73 and CN74)?
2) The room fan motor doesn't run.
3) The power voltage between terminal #3 and #5 of
the connector(CN73 and CN74) is 0V.
Cause
• Overcurrent
• Room Fan Motor Short
• ASS'Y Main PCB AC Pattern Short
• Poor Power Cord, Fuse Disconnection,
Wrong Power Cable Wiring, Poor AC Part
• Poor Switching Trans, Poor Power Circuit
• Poor Power Circuit, Load Short
• Relay(RY71) Coil Disconnection, Poor IC05
• Poor Relay(RY71) Contact
• Poor Room Fan Motor
• Poor Room Fan Motor Connector
(CN73 and 74) Contact
• Poor ASS'Y Main PCB
• Poor Connection
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