You may have poor connections on you LCD screen leads. I would first determine if the blinking is being caused by a loose connection or by something happening within the CB circuitry. The best way to do this would be to try to push and hold the LCD screen to stop the blinking if this works then your trouble is a loose connection. If it does not work then you may have some kind of internal problem. One such problem would the the IC driving the LCD screen you will need to have a schematic to troubleshoot this. The schematic will show you the voltage readings that should be on the pins of the LCD driver IC, and by measuring the voltages you should be able to determine which components are defective. You may also want to use a logic probe if the schematic contains a truth table of the states the pins sould be in under test conditions.
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