LG LSC27931SB Service Manual page 34

1-11. Communication circuit and connection L/Wire between main PCB and display PCB
The following communication circuit is used for exchanging information between the main MICOM of the Main PCB and the
dedicated MICOM of the LED Display PCB.
A bi-directional lead wire assembly between the two boards is required for the display to function properly.
Poor communication occurs if a continuous information exchange fail to continue for more than 2 minutes between main
MICOM of main PCB and LED dedicated MICOM for LED control of display PCB.
Main PCB L/Wire FD/H(4-wires) Display PCB
DC 12V
Main MICOM LCD(LED) dedicated MICOM
GND
Transmission (error status)
Reception (notch status)
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