Hello sir thank you for taking the time to read my email and give instruction. To be honest I am looking for the basics and some advice. Maybe some specials tools if you use them or techniques you have. From a video I seen you just pour water in the ultrasonic cleaner and put the board in, but I have also heard put alcohol in the water also. So just anything you can offer is helpful. Thank you.
Electrolytes dissolved in the water conduct electricity, and this causes water to become a liquid conductor of electricity. Increase the electrolyte concentration and you increase the conductivity of the water. Once this liquid conductor of electricity is inside your phone, circuits kept separate by insulators (mainly the fiberglass PCB, or printed circuit board) are now in contact with each other. This, as you can imagine, can cause all sorts of problems as electricity flows through pathways not designed for higher voltages. In addition, when you have two or more dissimilar metals (there are at least 10 of these inside your phone), an electrolyte (the water), and electricity (the battery), you get galvanic corrosion, which begins immediately and continues until one of those three things is removed. However, long after the water is gone, the corrosion remains.
This is where you’ll use water to repair water damage. You need to get the corrosion off the board. Some people simply soak the board in IPA (isopropyl alcohol). This alone is silly. IPA should NOT be your first choice of solvents to clean electronics unless you’re rinsing off flux residue. If your circuit board has BGA (ball grid array) microchips on it and it got wet, then there is a high probability that water is underneath the BGA packages and gets there by means of capillary action. Capillary action is the same process that glucometers use to check blood sugar. A test strip is inserted into the meter, and the end of the strip is held to a drop of blood. If you’ve ever witnessed this for yourself, it “looks” like the blood is magically sucked into the test strip opening. Feel free to Google “capillary action” for further explanation. Capillary action allows water (and other liquids) to actually flow against the force of gravity under the right circumstances, and unless the BGA chip is surrounded by underfill (a protective epoxy coating), if water is in the phone, then it’s also likely that water is under the BGA chips. No amount of IPA and a toothbrush will remove water from under a BGA chip. Furthermore, there are anywhere from four to over a hundred solder points under a BGA package. Solder contains various metals as an alloy. These metals become one of the ingredients for corrosion. Thus, it is reasonable to assume that if corrosion is on a logic board surface, then it is also under one or more BGA packages, causing short circuits. This can account for why certain microchips feel hot while others don’t. An over abundance of heat on a circuit board is almost ALWAYS a short circuit. Left unchecked, the short burns out and becomes an open circuit – both are bad.
So how does water “fix” water damage?
Ultrasonic cleaners work by a principle of physics known as cavitation. Cavitation is the rapid formation and collapse of bubbles within a liquid in region of very low pressure. Below is a drawing of what's occurring on a microscopic level to the tune of millions or billions of times throughout the ultrasonic cleaning solution. The yellow burst of the bubble is what removes corrosion from water damaged boards. You cannot actually "see" this process, but you can see its effects.
This is not the perfect solution to repairing water damage, but it is the best tool someone working on water damage can use, aside from a microscope and tiny soldering iron. Indeed, not even ultrasonic cleaning can save burned out components, and sometimes removing and replacing those tiny SMD packages is required when working on water damaged devices.
In another post, and future blog link, I'll answer the other part of your question Joseph and post some of the tools used to clean and restore wet phones. Someone else asked the same thing, so hopefully this week I can get around to doing that.
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