a. A couple of serial modules can’t be on, or there is other abnormity:

Check whether the flat cables of first abnormal module in the signal direction and the power cables have poor contacts. If no LED on the module is on, it indicates that no power is input. Then please check the power supply (use universal meter). If spotted images appears (bright spots with mixture color), it indicates that no signal is input. Then please check whether the input terminal of the flat cables for the first abnormal module is firmly contacted. You can plug it in and pull it out for times to test it. If the problem is not solved by that way, you can replace the flat cables.

b. Single module can’t be on:

Check whether the power supply for this module is normal, mainly whether the power plug on the module is loose. If color disorder or color inconsistency on the whole module appears (but have signal input and right image information), it is because the signal transmission flat cables have poor contacts. In this case, you should plug in and pull out the flat cables repeatedly, or replace the flat cables that have been tested. If the problem still exists even after replacement, please check whether there is any problem at the interface of PCB.

c. Single lamp can’t be on:

Use universal meter to check whether LED is damaged. If so, replace the lamp by following the descriptions in Item 5. Details for checking: Turn the pointer in the universal meter to level X1. For a pointer-type universal meter, connect the black pen to anode of LED, red pen to cathode (for a digital universal meter, connect the black pen to cathode, red pen to anode.) If LED is on, it indicates the tested lamp works. If not, the lamp is damaged.

d. Defected LED points(uncontrolled points):

If it is confirmed that LED is damaged upon the single lamp test, you can choose the maintenance method from the following based on the actual situation:

Front side operation

Use screwdriver with corresponding size to remove the cover’s screws from the front side (pay attention to properly keep the screws), then remove the cover and replace the lamp (please follow the instructions below for lamp replacement). After the replacement and sealing are completed, put back the cover and tighten the screws again (pay attention not to press the lamp). If there is any seal colloid left on LED surface, you should remove it with care.

Back side operation

Use screwdriver with corresponding size to remove the cover’s screws from the back side (pay attention to properly keep the screws). For the sack of safety, do not unplug the power line. Then carefully remove the module away from metal holes, and place it on the back of the case. After that, follow the same procedures as described in 4-1 to replace the lamp for single module (please follow the instructions below for lamp replacement), or check other parts.

d. Replacing the lamp:

Use sharp tools (like forceps) to remove the seal colloid around the broken LED, and allow LED pins to be visually exposed, use the forceps with right hand to clip the LED, use left hand to hold the soldering iron (with temperature about 40℃) and allow it to contact the soldering tin, the keep the iron on the tin for a while (not more than 3 seconds. If time is over and LED not removed, please wait till it becomes cool and then try it again) to melt the tin. Then use the forceps to remove LED. After that, insert the new conforming LED into the hole on PCBM, (long pin of LED is used as the anode and inserted into the square hole on PCB, and short pin as the cathode and inserted into the round hole). Melt some soldering tin and dip it on the iron head, use forceps to adjust LED’s direction correctly, then place the soldering tin onto the joint between LED and PCB. Use the colloid of the same type as before (PH value=7) to seal the LED properly.