In recent years, we began to receive cell phones filled with liquid. What do I need to know if moisture gets into the phone (water, juice, coffee, tea, etc.)? Let’s analyze mobile phone repair the example of Nokia.
1. When you fill the phone with liquid – you need to remove the back cover of the phone as soon as possible and remove the battery. This will help to stop the corrosion of the printed circuit board under the influence of electrochemical reactions (the so-called electrolysis process). And do not try to re-insert the battery into the phone and turn it on, hoping that the phone is “already dry” and, of course, do not attempt to charge the mobile phone.
The first signs of getting into the phone Nokia: on the glass there are divorces, the glass lags behind the adjacent plane of the frame, on the display substrate you see the divorce, when you press the buttons you need to press harder (the buttons do not work), badly catches the network, on the elements of logic, behind the battery, darkening, the indicator has become one-time or red, the microphone stops working in the normal mode, the phone periodically “buggy”.
2. The next step is to prevent the spread of corrosion on the board – cleaning. Your actions for de-energizing and removing the battery pack may not be enough, since a battery is soldered inside the PCB of the phone, responsible for the time and date when the phone is de-energized. Cleaning is carried out in two stages: cleaning the lines, cleaning the board.
For successful cleaning, you will need a work table with a good hood, a can of compressed air, special spray cans with traces, a set of professional screwdrivers, a bristle brush with increased bristles, an industrial dryer for soldering protective screens, a soldering station.
Even if all the components are in your possession, my advice to you is, take your phone to Nokia service. It is not enough to have tools, since one wrong move when the protective screen is soldered off and your phone can not be restored.
3. Flushing the phone. We will need an ultrasonic bath with an operating frequency of 30 kHz and an amplitude modulation of up to 90%, a purifier (medical alcohol will do).
4. Drying – deep at a temperature of 150 C. It is not superfluous to recall that the high penetrating power of water is due to the small size of the molecule relative to the capillary of the printed circuit board. When drying, the heating energy must break the physico-mechanical bond between the water molecule and the capillary.
5. Carpeting in places where the corrosion process has most progressed. We use industrial hair dryer. The temperature is selected based on the service standards for lead-free soldering.
In the case of low-quality Nokia soldering without observing the temperature and process conditions, an irreversible process of delamination of the internal layers of the board takes place.
6.Diagnostics of the phone using an oscilloscope, GSM tester, multimeter and other measuring devices.
7. Repair if a malfunction occurs.
From the practice of Nokia repair, you can confidently say that if you have exactly repeated the first item and delivered your phone to the service center as quickly as possible, then in 90% of cases, the seventh expensive item can be avoided.
8. Treatment of the entire board to prevent further spread of corrosion in new cases of moisture ingress.
The processing of the board on Nokia occurs in three layers. In addition, the loops and connectors on the cables are processed.
The cheapening of the technological process can lead to malfunctions in the operation of the phone after repair. It is also recommended to change the battery in the phone (if the battery is swollen). Repair is a rather complicated process, accompanied by constant monitoring and compliance with service standards.