FAQ For LED display Testing LED display quality assurance

FAQ For LED display Testing
LED display quality assurance

• 1 Q: What kind of tests will you have before delivery ?
• A: Appearance test, Electricity function test, Hi & Low Temperature test, waterproof test, vibration test, aging test, etc.
• 2 Q: How would you take the Hi & Low Temperature test?
• A: We have a professional Hi & Low temperature test workshop. We take samples from a batch of products, and test them as follows:
  a. Keep the product working under the temperature of (50±2) ℃ for 8 hours, check it once an hour and record the data.
  b. Keep the product working under the temperature of (-20±2) ℃ for 8 hours, check it once an hour and record the data.
  c. Store the product under the temperature of (60±2) ℃ for 4 hours and recover it under room temperature for 4 hours, check it and record data.
  d. Store the product under the temperature of (-30±2) ℃ for 4 hours and recover it under room temperature for 4 hours, check it and record data.
  e. Keep the product working under the temperature of (50±2) ℃ and related humidity of 87%~93% for 8 hours, check it once an hour and record the data.
  f. Store the product under the temperature of (60±2) ℃ and related humidity of 87%~93% for 8 hours, then recover it under room temperature for 4 hours, check it and record the data.
• 3 Q: Would you test all of your goods or some of them?
• A: Regarding different product, testing is different. For example, all the trailer screen need to take a vibration test more than 20 hours, and all the outdoor screens need to take the waterproof test. For standard products, we test the first trial products instead of testing all goods.
• 4 Q: How would you guarantee the screen can show the same display effect when it arrives customer’s place?
• A: We recorded the best effect parameters of the software and hardware, and give it to customers. As long as customers install the screen following the steps of User’s manual, the effect would be same as it in factory.
• 5 Q: How would you know the screen will not go bad after a long time use?
• A: When we have aging test, we will put the screen in an environment similar to the final working place, such as the weather, brightness, etc.
• 6 Q: How would you take the vibration test?
• A: Put the goods onto our professional test machine, and set the vibration rate as 250RPM more than 2 hours and then check it.
• 7 Q: Which kind of problem is the most frequently occurred in aging test?
• A:  Blind LED, controller problems, some rows or columns out of control, image disorderly, etc.
  

  Phenomena	Analysis	Solution
  1.Whole screen does not show any image	a. AC power not connected well	Check main power source and power cable, test the AC voltage on power supply
  	b. Power supply is not working	a. Check the switch is on the right position b. Check the cable connected with the power supply is loosen or not c. Check if there is DC output of the power supply, otherwise changed a power supply.
  	c. Computer can’t start	a. Check the right voltage of the country: 220V, 110V. b. Check and re-install system of computer: driver for graphic card; sending card; and other software conflict with system.
  	d. No DVI output signal(from computer):the green lamp of sending card is not flashing	Change display mode into CLONE mode in graphic card setting
  	e. Main UTP cable is broken.(after the above steps, the green lamps in the first cabinet still not flashing)	Replace a new UTP cable from sending card to first cabinet
  2.Whole screen display abnormal color	a. DVI port is broken b. RJ45 connector is broken c. Sending card is broken	a. Change graphic card of computer b. Replace a new RJ45 connector c. Change a new sending card
  3.When starting LED studio, a window reminds :LED screen system not found	a. The RS232 Cable is not well connected b. the COM port of the computer is broken.	Reconnect the RS232 cable between the COM Port in computer and sending card.
  4.Can not set up RCG file	RS232 cable is broken	Change a new COM cable
  5.Whole screen blinking with high brightness and abnormal image	RCG file is not well set	Reload the correct RCG file in “software setup” of LED studio and save in receiving card
  6, Each cabinet shows the same image	CON file is not set	Reload the CON file and save on the receiving card
  7, The image on the led display is showed in a confused order	The CON file is not set correct according to the data cable connection of the display	Reset the display connection page the same with the data cable connection mode when viewing from the front of the display.
  8, The brightness of led screen is low and cannot changed	Sending cards is not stable	Replace a sending card
  9, The picture on part of whole display is flashing	Data cable is loosen	Reconnect the UTP cable or re-insert the cable in the receiving card from the first cabinet where start flashing
  10 .One cabinet does not work	a. No power input b. No signal input c. Receiving card is broken (For b & c, green lamps on receiving card is not flashing)	a. Check power input b. Check UTP input cable or the output of previous output UTP cable c. Replace receiving card with new one
  11.One cabinet display different color with other cabinet	a. Receiving card is loaded with wrong RCG file or broken b. Hub board is broken c. Power supply broken	a. Set RCG file again or replace a new one b. Replace a hub board c. check the power supply and change a new one
  12.One module does not work	a. No power input b .No signal input c. Module is broken	a. Check if the module connected with DC power b. Check input flat cable or the output flat cable of previous module c. Replace with new one
  13.One module shows abnormal picture	Some IC are broken or not soldered well	Replace a new module
  14. LED is lighting constantly or fade	LED Lamp is broken	Replace a new module

• 8 Q: How could you guarantee the accessories are all ok?
• A:  We will test all of the accessories, including system, cables, brightness sensor card, and video processor and so on before delivery.
• 9 Q: How long will you take the aging test?
• A: Not less than 72 hours.
• 10 Q: What kind of positions you have for quality control?
• A:  IQC: for material quality control
  QE: for following the producing process, record the problems and improve it in the future.
  IPQC: for checking the quality of every step.
  QA: for last check before goods delivery.