Electronic Parts Troubleshooting Guide - LG LS-J0761NL Service Manual

Electronic Parts Troubleshooting Guide

❇ Refer to electronic contorol device drawing & schematic diagram.
The Product doesn't operate at all.
Trouble 1
Check the voltage of power(AC220V/AC240V, 50Hz).
• The voltage of main power.
• The voltage applied to the unit.
• The connecting method of Indoor/Outdoor connecting cable (each color)
• The P.W.B. Ass'y
(Fuse, Noise Filter, Power Transformer, Bridge Diode, etc.)
The operation check of the P.C.B. Ass'y
Procedure
1) The input voltage of power trans-
former.
2) The output voltage of power
transformer.
3) IC01D(7812)
4) IC02D(7805)
5) IC01A(KIA7036)
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Only for training and service purposes
Turn off the main power and wait to 5 seconds
Turn on the main power again.
Does "Beeping" sound is made from the indoor unit?
NO
Specification
1) AC230V ± 30V
: Check the rated voltage
2) 14V ± 3V
3) DC12V
4) DC5V
5) The voltage of micom pin 29
: DC4.5V↑
- 56 -
YES
• Primarily, the operating condi-
tion of Micom is O.K.
• Check CN-DISP1
CN-DISP2
Remedy
1) Replace
power transfomer.
2) Replace
power transfomer.
3) Replace IC01D.
4) Replace IC02D.
5) Replace IC01A.
LGE Internal Use Only