How do you fix a broken printed circuit board?

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Steps？

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Alina 4 years 1 Answer 829 views 0

Answer ( 1 )

  1. Miki
    0
    December 31, 2019 at 10:57 AM
    How do you fix a broken printed circuit board?

    There are many reasons for PCB damage, such as the open circuit of the inner layer, etc. This kind of repair requires reverse engineering. For detailed repair steps, see this post. https://top10pcb.com/how-to-do-pcb-reverse-engineering.html

    Secondly, most of the most common PCB failures in daily life are caused by thermal damage, physical damage, and excessive component voltage.

    The components on the PCB shown in the picture above are thermally damaged.

    Although the glass fiber, copper wire, and glue coating inside the circuit board can prevent heat buildup to some extent, some PCBs are indeed more prone to delamination and other thermal damage than others.

    First, prepare the tools and materials needed to repair the PCB:
    Sharp knife or flat head screwdriver or fine sandpaper
    Copper foil tape
    Welding torch
    Hot air gun
    Scissors or craft knife
    pen
    Cotton swabs and alcohol wipes
    tweezers
    paper clip

    Then follow the steps below to repair the damaged PCB and return it to normal function:

    Step 1: Remove the damaged pad or component. First, fix the PCB on the workbench so that it will not move during operation. It is best to use tape.
    To diagnose a damaged PCB, an oscilloscope is sometimes used to detect the signal strength and waveform of each point and test the circuit continuity of the entire board. Sometimes it is as simple as finding the burned-out area, replacing the faulty component, pad or trace, and reconnecting it to the existing copper wires of the PCB.

    If you find that a component on the PCB is not working properly, you can remove and replace it with the following simple steps:

    -Pick up the hot air gun and turn on the switch. The hot air gun should be at least 6 inches from the faulty component.

    -After a few seconds, remove the component with tweezers. If it does not remove, heat for a few more seconds and try again.

    -If the PCB pad is thermally damaged, it is best to use a sharp knife to carefully remove it. Care must be taken not to damage copper wires and other nearby components when removing damaged components from the board.

    Step 2: Clean the copper wire and remove the solder. After removing the damaged pad, continue to use a sharp knife to remove the solder on it. If using a knife is not convenient for this fine operation, you can also use a pointed screwdriver or sandpaper with fine grit.
    No matter which tool is used, the copper wire should be completely exposed at the end, without any solder left, and it looks clean and shiny.

    Step 3: Attach the copper foil tape to the copper wire. After the damaged copper wire has been removed and the area is cleared, the copper foil tape can be applied to it.
    The copper foil tape should overlap the existing copper wire and cover the existing through-hole and a part of the surrounding area.

    Step 4: Weld the joint. At this time, it is necessary to carefully solder the joint of the new copper foil tape and the copper wire of the repaired PCB. Here are some related tips and warnings:
    Copper foil tape melts quickly at the soldering temperature, so it must be determined that it can be done in one go.
    As little heating as possible must be done carefully and quickly to reduce the amount of heat applied.

    Step 5: Restore the PCB through-holes. Find a hard tool with a round head, such as a pen or other simple tool. Press on the area that has just been soldered and wipe firmly to ensure that the copper foil tape is firmly fixed on the entire pad area. After the area was heated, the tape remained sticky.
    Use this technique to locate the through-holes and then use a paper clip or other similar tool to make the holes.

    Step 6: Place the components and solder them. After completing the above steps, the PCB is repaired and the new component selected can be accepted.
    The process of soldering components is very familiar to everyone. As before, heat as little as possible. The new solder joint between the newly applied copper foil tape/pad and the copper wire may not yet be strong.

    Step 7: Cut off excess tape from the repair area. Using scissors or craft knife, carefully cut the copper foil tape to the appropriate size to complete the repair. It must be noted that the newly repaired solder joints may restore the functionality of the PCB, but the pads, copper wires and connectors will no longer be as strong as previous circuit boards.

    However, this is already quite remarkable, and you have given new life to something that many others will discard as garbage.

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