Pcb Inspection Method - Samsung FH070EAV Servise Manual

12-3 PCB Inspection Method

12-3-1 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 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. In case of outdoor PCB disassembly, check first the complete discharge of condenser (C103) after 30 seconds power off.
12-3-2 Inspection Procedure
1. Check connector connection and peeling of PCB or bronze coating pattern when you think the PCB is broken.
2. The PCB is composed of the 3 parts.
1. ● Indoor Main PCB Part : MICOM and surrounding circuit, relay, room fan motor driving circuit and control circuit,
1. ● Display part : LED lamp, Switch, Remocon module
1. ● Outdoor Main PCB part : MICOM and surrounding circuit. IPM and PFC circuit and control circuit.
1. ● EMI PCB Part : Line filter and Noise Capacitor, Varistor
12-3-3 Indoor Detailed Inspection Procedure
No Procedure
1 Plug out and pull the PCB
out of the electronic box.
Check the PCB fuse.
2
Supply power.
If the operating lamp
twinkles at this time,
the above 1)~3) have
no relation.
12-18
sensor driving circuit, power circuit of DC12V and DC5V, and buzzer driving circuit.
Inspection Method
1) Is the fuse disconnected?
Checking the power voltage.
1) Is the DB71 input voltage AC200V~AC240V?
2) Is the voltage between both terminals of the
C104 on the 2 side of the transformer DC12V
nd
±0.5V?
3) Is the voltage between both terminals of OUT
and GND of IC19(KA7805) DC5V ±0.5V?
Cause
•
Over current
•
Indoor Fan Motor Short
•
AC Part Pattern Short of the MAIN PCB
•
Power Cord is fault, Fuse open. Wrong Power
Cable Wiring, AC Part is faulty.
•
Switching Trans or Power Circuit is faulty
•
Power Circuit is faulty, Load Short
Samsung Electronics