Electronic Parts - LG LA090CP Service Manual

Troubleshooting Guide

Electronic Parts

2. Product does not operate at all.
(* Refer to Electronic Control Device drawing and Schematic diagram.)
Check the voltage of power(About AC 208V/AC230V, 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(ZNRI)
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
• IC2(7812) Output
(Indoor/Outdoor unit)
• IC3(7805) Output
(Indoor/Outdoor unit)
• IC4(KIA7036, Reset IC)
OSC01B(4MHz)
(Indoor/Outdoor unit)
38 Room Air Conditioner
Turn off Main Power
Turn on Main Power
Does "beeping" sound is made from the Indoor Unit?
NO
PCB Board Operation Check
- About AC208V/230V ± 10% - Check the power voltage
- About AC17 ± 3V
• DC + 12V
• DC + 5V
• Voltage of Outdoor unit Micom No. 8,
Voltage of Indoor unit Micom No. 43 and soldering
condition
(After 10 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
YES
Remedy
• Replace Trans
• Replace IC2
• Replace IC3
• Replace faulty parts