Communication Error - LG LM-2421C2L/A2L Service Manual

6. Outdoor unit does not operate at all.
Items
• Power Transformer
(Outdoor unit)
- Input Voltage
- Output Voltage
• IC01D(7812) Output
(Indoor/Outdoor unit)
• IC02D(7805) Output
(Indoor/Outdoor unit)
• IC01A(KIA7036, Reset IC)
X01(8MHz)
• Check the electrical wiring diagram of outdoor side.
• Check the abnormal condition for the component of
Compressor/Outdoor Fan Motor/4-way.
• Check the "open" or "short" of connecting wires between indoor and
outdoor.

7. Communication error

• The control data can be transmitted or received between indoor and outdoor unit with one signal cable.
• If the data be disturbed by any noise level, the unit will be operated incorrectly. In this case, the indoor unit
blinks the operation and operation LED on display and indoor fan, outdoor fan, COMP are not operated.
• The unit can be reoperated by On/Off control of Remocon.
Check Outdoor Unit
PCB Board Operation Check in Outdoor
Content
- About AC220V/240V ± 10% - Check the power voltage
- About AC14 ± 3V
• DC + 12V
• DC + 5V
Turn off Main Power
- 45 -
Remedy
• Replace Trans
• Replace IC01D
• Replace IC02D
• Replace faulty parts