LG LAN121CNM Service Manual - Page 50

Troubleshooting Guide Electronic Parts 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 115V, 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) 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) 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 PCB Board Operation Check Content Remedy - About AC115V±10% - Check the power voltage • Replace SMPS - About DC15V±3 Module • IC01D(7812) Output (Indoor/Outdoor unit) • DC +12V • Replace IC01D • IC02D(7805) Output (Indoor unit) • DC +5V IC03D(7805) Output (Outdoor unit) • IC01A(KIA7036, Reset IC) Indoor : 16MHz Outdoor : 8MHz • Voltage of Outdoor unit Micom No. 18, Voltage of Indoor unit Micom No. 43 and soldering condition • Replace IC02D(Indoor unit) IC02D(Outdoor unit) • Replace faulty parts 50 Room Air Conditioner