LED display play when there is a bright line?

LED display is a complex screen LED lamp bead polymerization. Composition including unit board, control card, power supply, housing and bracket, etc. Recently a friend of screen play when the bright line. Have not been able to solve, and finally I contacted the powerful giant colour technicians to be able to think. Here is to share the solution. First determines the power if there is any damage, still can normal use. Because of a power unit controls a few board at the same time. Whether can measure the output voltage in 4. 9 to 5. Between 5 v. Is beyond the scope of the word, is likely to be the power supply is broken. Then check that the control card is the normal use. Turn on the power supply first, look at the control card whether indicating light; If not bright, inspect whether there is 5 v voltage power supply, LED electronic screen can display content, if we can display content, control card display function is good; Then search control card with control card software, if we can find the words, explain the function of the control card to send content good; If not find, have to check the communication lines connected, if ok, it is likely to be card is out of question. As long as the two function is good, the control card is ok, otherwise will replace the control card. Finally, look at the led unit board is good. LED display of the signal from one plate to another board input. So there is a plate out of the question, will affect the back of the plate. So one by one to check whether the unit board is normal. Even if you can check out the problem, damage to the unit board, should contact the supplier for repair in time, to ensure the normal use of LED electronic display screen.