This problem not only occurs at the beginning of controlling LED screen but also maybe occur after LED screen working several months or years.
Question: Why there are some parts no displaying on LED screen?
a) Power Supply Break down
Solution: Check if the power supply of cabinet is working normally
b) No input Signal
Solution: Check if the receiving card have input signal (green indicator twinkling)
c) Receiving Card break down
Solution: Check if the receiving card is working normal (green indicator twinkling, red indicator keep lighting). If the green indicator is off or keeps lighting, it means there is no signal (if the indicator is off, it may be also because its power is off). If it truly breaks off, please change the receiving card.