5. Defect Diagnosis and Repair
Phenomenon
Defect Diagnosis
Defect Mode
How To Handle
Pollution level display lamp is not on.
Contact point of micro switch is right?
Power consent voltage is right?
PCB input power(CN1) is AC 220V?
Connection between power code
and connector?
FUSE is opened?
Bad power if it is under 180V
If power is irregular or OV
Bad connection to power
connector
FUSE Open
Bad micro switch
Faulty Power
↓
YES
↓
YES
↓
YES
Check input power
FUSE change (250V ,3A)
Right contact of connector
Bad contact of consent or
power interruption
Micro switch change
Micom operation voltage is DC 5V?
LED connected cable is opened?
↓
YES
Bad LED connected Cable
Bad power circuit of Main PCB
LED Cable check and change
Main PCB check and change
NO
→
→
→
↓
YES
↓
YES
NO
→
→
51
YES
→
→
↓
NO
NO
→
→
NO
→
→
NO
→
→
