I already wrote about what to do if your phone gets wet, and among all the advice there was one about how not to harm an already wet phone – not to turn it on. Few people succeed in following this simple rule. This is one of the most common mistakes, which is difficult to avoid due to the fact that after dropping the phone into the water, the first thing you want is to check if the phone has survived bathing, and for this it must be turned on. At the moment the voltage is applied to the wet elements of the electrical circuit, an intensive process of electrocorrosion starts, which kills the electronics. Here is HERE you can see how it happens in real time.
Today, we will try to eliminate the consequences of trying to turn on a wet phone, which also broke the display when dropped.
As a patient – a device from Xiaomi model Redmi 4X, which, when switched on, fell into the shower room on the tiled floor. Well, according to tradition, after the phone was taken out of the water, they tried to turn it on to check if it survived the water procedures.
Our task is to get inside the phone in order to assess the degree of damage, assessing the feasibility of repair.
The phone is easy to disassemble – we pry the back cover with a plastic tool and snap it off around the perimeter.
After that, we are in no hurry to remove it so as not to damage the fingerprint scanner cable.
We unfasten the cable connector, and here we have an internal protective screen and a lower antenna block, screwed to the body with screws. We unscrew them and get to the boards. Please note that there are moisture indicators on the board, which are white stickers that, upon contact with water, change color to pink or red. This is the easiest way to determine if moisture has entered the phone.
Now our task is to assess the damage that the liquid has done. We disconnect all connectors and cables and carefully examine the board for visible damage and burnout.
In general, the situation is not as dire as it could be, as the owner of the phone remembered my advice and hardly tried to use the phone after it got wet. Almost, because, alas, it was not without an impulsive attempt to switch on.
Because of this, the expectedly greatest damage is visible at the point where the voltage is applied. This is the battery connector, as well as the power button connector, through which the voltage flows at the moment of pressing.
Due to the fact that there was only one attempt to turn it on, the owner was lucky that the loop of the touchscreen and display did not suffer much – the contacts remained intact, only darkened from corrosion.
We clean them with a cotton swab with alcohol, make sure that there are tracks under the dark layer, and put them aside.
We continue the inspection and see that the power button loop got very good, the tracks on which were eaten by electrocorrosion when trying to turn on the wet phone.
Let's hope that's why the phone didn't turn on then.
The part is cheap, and it's easier to buy than to bother with the restoration, but I have no choice, since the suppliers did not have this cable, and the owner needs the phone as soon as possible because of the data in memory necessary to solve current work tasks.
Since the area of damage is small, we will do without thin wires, among the masters called 'cockroach pipi..ki'. Cockroaches can sleep well. Instead, we arm ourselves only with a soldering iron, flux and solder and proceed to resuscitate the loop.
As a result, preparation took more time – the loop was restored in three minutes. Now it shines and sparkles.
We put the restored cable aside and go to the board.
In an amicable way, the board can be bathed in an ultrasonic bath filled with alcohol. However, this is an extreme measure, and, given the insignificant nature of the damage and a small amount of traces of moisture, we will manage to dry the board in a warm dry place – under an incandescent lamp (for 5-6 hours), followed by mechanical cleaning with cotton swabs and still the same alcohol. By the way, for hard-to-reach places, you can use wooden toothpicks, which also perfectly absorb alcohol. Just be careful not to rip the elements off the board.
After the main board is cleaned, we do the same with the bottom board and connectors of all cables.
After that, we dry the board again for half an hour (now from alcohol) and, hoping for the owner's luck, we assemble the phone without closing the covers and try to start it.
As a result, the phone turned on without any problems and at first glance turned out to be completely serviceable.
But it's too early to rejoice – after switching on, you need to check if there are any short circuits on the board. Ideally, this requires the use of special equipment. However, we have available equipment more abruptly and at the same time without a gram of electronics – a finger!
Yes, this is unprofessional, but it allows you to get almost the same reliable measurement result, because a faulty element that has a short circuit should get very hot. And this can be easily identified with our super-technological finger.
No overheating was found, which means that the resuscitation was successful. We collect to the end and give it to the happy owner. We'll replace the broken display later.
The owner was lucky twice. The first time was that the liquid did not flow into the display backlight, and the second time was that the power button cable saved the rest of the phone at the cost of its own life, taking the brunt of electrocorrosion upon itself when trying to turn on the wet phone.
It turns out that the owner got off with little blood – cleaning, drying and restoring the trails of the train. But it should be understood that this is not always the case. If the power button cable were stronger and more resistant to corrosion, the consequences for the phone could be much more serious. Do not ignore the advice on the need to turn off and not turn on a wet phone, and if the phone gets wet, rather take it to the service. Or, if you feel the strength and skills, disassemble and reanimate yourself, it's not difficult. And may this experience be successful.