P3.91 series Circuit Paper，Double-sided solder pads, fully covered with large holes ,Used for repairing damaged PCB pads

1、How to choose a circuit paper?

1）The pixel pitch of the original LED module needs to be consistent with the circuit paper;

2）The original LED bead specifications need to be consistent with the circuit paper;

3）Some products have differences between vertical and horizontal lamps (vertical lamps are more common, while horizontal lamps are less common); If the original LED module is a vertical lamp, the circuit paper for the vertical lamp should be selected.

2、Measurement method for the pixel pitch of LED module

1) Measure the horizontal dimension(W) of the LED module using a caliper ;

2) Count the number(N) of LED lamp beads in the horizontal direction ;

3) Calculation: Pixel pitch (P)=The module size (W)/The number of lamp beads (N)

【Numerical accuracy to 0.000】

3、Measurement method for LED bead specification

1) Measure the horizontal dimension (X) of LED beads using a caliper;

2) Measure the vertical dimension (Y) of LED beads using a caliper ;

3) Calculation: LED bead specification=SMD (X) (Y);

4、The difference between vertical and horizontal lamp (as shown in the figure)

5.What is the Circuit Paper?

Circuit Paper is a kind of double-layer flexible circuit board。Its thickness is only 0.08-0.1mm。

6.Composition of the Circuit Paper?

Circuit Paper is composed of screen printing,base material, pads,holes, wires and cutting line ect.

7.Where is the Circuit Paper used?

The collision of LED display during installation, disassembly and transportation can easily lead to PCB pad falling off. At this time, you need to use the Circuit Paper to repair PCB.

8.How to use the Circuit Paper?

First step, you need to prepare the following maintenance tools and consumables: anti-static bracelet, soldering iron, hot air gun, multimeter, tweezers, tin wire, solder paste, scissors, screwdriver, lamp beads, Circuit Paper, IC, etc.

The second step is to clean the damaged pad, scrape the damaged PCB pad with a knife blade, and wipe it with alcohol to prevent short circuit with the Circuit Paper.

The third step is to cut different sizes of Circuit Paper and tin on both sides of the pad, so that the short circuit of the lamp foot can not be caused by too much tin.

The fourth step is to adjust the soldering iron temperature to about 320 ℃, clamp the tin-coated Circuit Paper with tweezers on the left hand, align it with the position of the soldering pad of the PCB lamp tube, press it gently on the pad, and then heat it with soldering iron or hot air gun to make the Circuit Paper and the PCB pad fully fuse, pay attention to the common poles to be aligned;

The fifth step is to light up the module, display in full white, adjust the brightness to the acceptable range for naked eyes by sweeping obliquely, weld the qualified beads to the Circuit Paper, pay attention to the polarity direction of the beads, and test whether the pins are connected with the multimeter before welding；

Step 6: after the module test is qualified, the lamp beads in the maintenance part need to be filled with glue. (indoor module does not need glue filling)；