LG LSN090CE Service Manual page 53

Electronic Parts (18k model)
Product does not operate at all.
(* Refer to Electronic Control Device drawing and Schematic diagram.)
Check the voltage of power(About AC 208V/AC 230V, 60Hz)
• Main power's voltage
• Voltage applied to the unit
• Connecting method of Indoor/Outdoor connecting
cable
• Check PWB Ass'y(Outdoor unit)
- Fuse
- Pattern damage
- Varistor(ZNR01J)
Check the connection housing for contacting
• Connector related to CN-POWER
• Connector related to CN-FAN
• Connector contacting of Outdoor Fan/Compressor
• Display PWB Ass'y Check
• Connector related to CN-DC/DC
Items
• Power Transformer
(Outdoor unit)
- Input Voltage
- Output Voltage
• IC01D(7812) Output
(Indoor/Outdoor unit)
• IC02D(7805) Output (Indoor unit)
IC04D(7805) Output (Outdoor unit)
• IC01A(KIA7036, Reset IC)
OSC01B(4MHz)
(Indoor/Outdoor unit)
Turn off Main Power
Turn on Main Power
Does "beeping" sound is made from the Indoor Unit?
NO
PCB Board Operation Check
- About AC 208V/AC 230V ± 10%
- Check the power voltage
- About DC15V ± 3
• DC + 12V
• DC + 5V
• Voltage of Outdoor unit Micom No. 18,
Voltage of Indoor unit Micom No. 43 and
soldering condition
(After 20 seconds)
Primarily, the operating condition of Micom is OK.
Check each load(Indoor/Outdoor Fan Motor,
Compressor, Stepping Motor) and contacting
condition of related connector(including connecting
cable of Indoor/Outdoor Unit)
Content
Troubleshooting Guide
YES
Remedy
• Replace SMPS
Module
• Replace IC01D
• Replace
IC02D(Indoor unit)
IC04D(Outdoor unit)
• Replace faulty parts
Service Manual 53