I have observed that computers (phones, laptops, desktops, etc) with water damage do not always completely stop working. They can have intermittent issues such as freezing, random shut downs, etc.

I understand that corrosion is caused by impurities in water and that is what causes the actual damage to the hardware.

What I do not understand is how they are able to function at all when there is corrosion.


Obviously the corrosion is what causes the random reboots and shutdowns.
Explain technically what is going on and why it is able to function at all. What is the reason for it to randomly shut down and reboot.

"Just because of corrosion" is not the answer I'm looking for. Give a technical explanation in your answer.

Image below is just a random example of corrosion.

enter image description here

  • 3
    Most devices damaged by water, are damaged by short-circuiting pathways, in a way that damages the pathway or components attached to it by failing to observe the electrical specifications of the hardware (ie Amperage, etc) . Jan 23, 2018 at 17:37
  • @FrankThomas That seems like an answer not a comment. Care to elaborate and explain that a little more? Jan 23, 2018 at 17:51
  • The reason is that it isn't all or nothing. It's just like why don't you die if you get burned? It depends on where, how much, and how severe. Corrosion can have no effect at all, it can be fatal, it can cause intermittent problems, it can affect an area that isn't in frequent use, etc. It all depends on what was affected, how it was affected, how badly it was affected, etc.
    – fixer1234
    Jan 24, 2018 at 11:49
  • @fixer1234 Yeah obviously. I'm familiar with water damage. I wanted a technical explanation. Not a metaphor. Jan 24, 2018 at 14:48

1 Answer 1


Comment: I'm not a native English speaker and I'm not working in the electronics industry for quite some time, so excuse if some technical terms are not on the spot or grammatically properly written.

Why do they still work?

Well, simplistic said, because for the electric all seems normal. The water might not be in areas where it can cause havoc (because of measures taken not explained here). However, for simplicity lets assume, we have an area with corrosion that might potentially create issues.

The majority of parts - in view of their count - on a PCB (Printed Circuit Board) are usually passive ones. For example these are resistors and condensators. Almost all rectangle shaped parts on your example picture should be condensators (size 1206 down to 0402 Imperial, I assume - more on Wikipedia). As you can see, there are open solder points (they don't seem to be lacquered). If water comes in this area and corrosion happens, you might get either a electrical bridge between these contacts or the solder point might corrode, resulting in a reduced electrical conductivity.

Resistors are often used to prevent other circuits - often controllers - from getting too high voltages at their inputs. Condensators then are commonly used to "smooth out" the voltage or to work as a buffer of some sort. There are (way) more use cases for both of them, but I want to emphasize these because they're important for our context.

Now, the actual "heart" of almost every electronic device is of course a microcontroller of some sort. We want to protect them with all reasonable effort because if they fail, the device might get unusable (or even destroyed). So all other parts (way more than I stated above) around trying to supply them with the required signals, so they can execute the code that's running on them in the expected way.

Shutdown reason 1: Unsteady voltage supply

Now, assume for example, we have a corrosion issue in an area that's responsible for the voltage supply of some of our micro-controllers (i.e. in a phone). Also assume, condensators are affected that should supply controllers with a clean, smooth direct current. However, because of the corrosion they don't work as expected anymore. They might still have contact but not as the manufacturer expected it. The result will be a more unsteady voltage supply for the controller. If the voltage drops are big enough, the controller might be forced to switch down and subsequently the phone might get turned off.

Shutdown reason 2: Overvoltage protection

Extend the thought from the example above, but this time assume the affected parts are resistors. The effect on the electrical connectivity is the same. However, we assume that the electrical circuit is designed in a way (resistor network) that a voltage greater than expected comes to the controller. Ideally, the controller will be able to handle the full operating voltage at least for a short time. To prevent further damage, it might turn off itself and the device after that (ofc good design recommends there should be something logged then, although you as customer might not able to get to it).

Shutdown reason 3: Overcurrent protection

Similar to overvoltage in principle. However, now assume we have a "classical" short circuit between two or more pins of a controller. Often, that's not necessarily an issue because some pins might not even be connected for example. However, if you're connecting the "right" two pins - most notably the power supply - you should hope, the controller has a proper overcurrent protection. Most likely it will turn off itself when noticing a short circuit there and turn the device off after that. Or you might have luck and a fuse gets tripped fast enough to prevent further damage (unfortunately, not a lot of consumer devices have changeable fuses).

Shutdown reason 4: Overtemperature protection

Again, the assumption is similar to the previous ones. A temperature is often derived with specific resistors that change their resistance when the temperature changes. With old computer power supplies this was often done with NTCs for example, actual ones are more sophisticated. Anyway, we're calculating the temperature in some way or another. Now, when electrical connectivity issues are happening, we might get wrong or implausible signals. To prevent further damage (and because the controller usually will go the safe route), the device might shut down. Of course, there also might be real temperature issues in such cases, but you should find that out relatively easily (at least with phones).

I would go on and explain what are commonly used techniques to avoid these failures but I feel for the moment, it should suffice as an answer to your question.

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