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The big problem here is not just that you should clean the obvious green corrosion away from the area, but that it needs to be neutralized chemically to protect the board from further corrosion inside. What you may not be aware of is that most motherboards are what we call 4 layer boards. Besides the printed circuit traces on the top and bottom - the printed wiring we see here as a gold or copper color, there are two more layers of similar traces inside the board. Like a sandwich with four slices of bread and meat in-between each slice, we have 4 layers of copper with three thin layers of fiberglass inside. First copper, then fiberglass, then copper then more fiberglass and then more copper and a last layer of fiberglass topped with copper.

While the copper traces in the two internal layers are usually less complex in design, they don't have to be. Corrosive chemicals get into a connection that goes through the board or just connects to the internal layers, and it will start to eat away the copper - even inside. Scraping the corrosion off on top stops that visible corrosive effect, but may do little on the part that is eating away at the copper inside or under a layer of paint on top. Most batteries use chemicals that can be either acidic or base - and the corrosion can be stopped by using the opposite material. For an acid leak, we can use a paste of baking soda and a bit of water applied with a old toothbrush. Scrub the area gently but thoroughly, and allow the paste to stay on for a bit. Then rinse off with distilled water if available - or bottled water if not. If the battery leakage is alkaline - a base, then we can use an acid to clean and stop the reaction. Vinegar is good for that purpose. Again leave it on a bit - then rinse well with distilled water.

A word of caution - the problem with liquids and circuit boards is that the capillary action of liquids will draw the liquid up under parts - especially integrated circuits, sockets, and similar parts. So if you don't have to get the cleaning solutions - acid or alkaline, under these parts, don't. If you did not have chemicals under the part then try to avoid getting the rinse water under the parts - as it will be harder to get out than you might think. If you do get corrosion under a part - it may be that you will need to remove that part to clean under it, or if minor you might be able to put the opposite chemical solution under the part and then rinse it out. Once it is wet you must be sure to get it dry - and that will often take warm air drying or dry air pressure. Standard compressed air will often have moisture in it and that can prevent you from drying the part well.

When you have some corrosion on a copper trace, you can use a razor knife to scrape gently on the top of that trace, removing the coating till you see bright copper. If your copper is very dark or mostly erroded away - you can replace that trace using some small gauge wire - or in some cases insulated wire (I often use wire-wrap wire with that thin clear colored insulation).

Computer circuits are often very delicate not only in size but in signal with low voltages - often 5 volt or 3.3 volt and just millionths of an amp in current flow. Any resistance can cause these delicate signals to be weakened or lost. And... you guessed it, the corrosive chemicals are conductive and resistive enough to cause some unpredictable results. So when you see a slight green cast to an area and you don't clean it off - it could cause all sorts of problems from nothing to preventing your board from booting up.

It is my sincere hope that this page and the information here will help you avoid some problems and fix others. It can take a board that might be useless, and allow it to live again. While I have done this for many many years and learned much of it from doing, from my studies and from trial and error - I do not claim to be the grand wizard of this. If you have a different view - I would be glad to hear it. If it's better or helpful to this work - I would be glad to correct or amend as needed if you approve sharing it here. The goal of this site is to be helpful and I am glad to share others ways of doing something if its better. 

I started building electronics, soldering kits with delicate parts over 50 years ago, and I am still sure that I have more to learn each day. 

 

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