LG Electronics Troubleshooting Tips for Your LS120CP Air Conditioner

Troubleshooting Guide

ElectronicParts(18k model)

Product does not operate at all.

(* Refer to Electronic Control Device drawing and Schematic diagram.)

Turn off Main Power

(After 20 seconds)

Turn on Main Power

Does "beeping" sound is made from the Indoor Unit?

NO

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

YES

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)

PCB Board Operation Check

Items		Content	Remedy
• Power Transformer
(Outdoor unit)
- Input Voltage	- About AC 208V/AC 230V±10%		• Replace SMPS
- Output Voltage	- Check the power voltage		Module
• IC01D(7812) Output	- About DC15V±3
	• DC +12V		• Replace IC01D
(Indoor/Outdoor unit)
• IC02D(7805) Output (Indoor unit)	• DC +5V		• Replace
IC04D(7805) Output (Outdoor unit)			IC02D(Indoor unit)
• IC01A(KIA7036, Reset IC)	• Voltage of Outdoor unit Micom No. 18,		IC04D(Outdoor unit)
OSC01B(4MHz)	Voltage of Indoor unit Micom No. 43 and
(Indoor/Outdoor unit)	soldering condition		• Replace faulty parts

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