Diagnostics, Troubleshooting and Repair of Cell Phones

Hello, in this article we tell how to fix and diagnostics cell phone. Like any complex technique, cell phones often fail when used actively. This can happen for a variety of reasons, such as factory marriages, long service lives or the careless handling of the owner with the phone. The main reasons for the breakdown are frequent falls, water entering the phone, bathing the phone in water (fell into the river, got into the washing machine), non-observance of the rules of operation of a particular model or simple negligence, because many phone models are very fragile in circulation. For example, clamshell models are often broken by carelessness.

If the phone breaks down, the owner begins to look for a repair location for cell phones and comes to the service center to a repairman for help. And in this situation, the master must quickly and skillfully conduct a primary diagnosis of the cell phone and repair it if necessary.

In general, the diagnosis of malfunctions is a kind of art, based, first of all, on a deep understanding of the operating principles of the device. Without this, it is impossible to master the art of repair perfectly. Below we give a general approach to the repair procedure using the example of the Nokia 6020 phone, and training in our courses, as well as your patience, accuracy and attentiveness will allow you to gain experience and polish your skills.

Malfunctions of mobile phones can be conditionally divided into three types:
– mechanical damage;
– failure of electronic components;
– Incorrect operation of the phone software.

Mechanical damage
Mechanical damage is detected by visual inspection, including by means of optical instruments – a magnifying glass and a microscope. It should be noted that even small external damages that appear after the impact or fall of the phone, as a result, can lead to the formation of a microcrack in some contact track, which in turn leads to a total inoperability of the phone. Most often, the chips suffer from the chips of transmitters and antenna switches assembled on a ceramic base.

Failure of electronic components
Universal Test
The failure of electronic components, as a rule, is accompanied by a change in the current consumed by the phone. There are so-called rapid tests, which are based on the measurement of the current consumed. Some manufacturers, such as Nokia, in the technical manuals give algorithms for such tests. However, as a result of the test, we can only talk about the probability of failure of one or another element, although this probability can be quite high. For testing, it is necessary to take out the battery and connect an external power supply with a voltage of 4.2 V to the battery contacts of the phone, preferably it is a stabilized power source, with indication of the current output.

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The phone is switched off.
The current consumed by the switched off phone is 0. In the phones, two chips are directly connected to the battery – a power amplifier (transmitter) and a power controller. A faulty power controller consumes approximately 300 – 400 mA, and a faulty power amplifier may give a short-circuit (short circuit). That is, if the phone immediately consumes 300-400 mA when it connects to the power source (we do not press the power button at the same time), then the power controller is likely to be faulty and it needs to be replaced, in this model the power controller is called UEM. And if, when connected, the power supply stabilizes and stops feeding current to the phone, and the multimeter in the continuity mode shows a low resistance and “peeps”, it is possible to remove the power amplifier and check the phone for activation. If the phone is switched on, then we install a new power amplifier.

The initial current is 0.
Push the power button. If the current is still 0, then either the breaker, the closing circuit, or the power controller is faulty. You can check this chain by disassembling the phone.

Start disassembling the phone
Next, you should visually inspect the power button. Then you need to measure the voltage on it, if the voltage on it is (about 4 volts) and when you press it it drops to zero, then the switching circuit is working. In this case, the UEM power controller is likely to be defective or undamaged.

The UEM power controller can be soldered with a thermo-foam from a Lukey-702 soldering station. We will put on the microcircuit a little flux-free flux.

Let’s install the thermofan to a temperature of about 280 ° C. Carefully warm up the microcircuit. After warming up, it is necessary to clean the board with a spray-cleaning board, for example, FLUX-OFF

After that, the phone either turns on, or it can drive as follows.
If the current is approximately 50 mA when the button is pressed and disappears before the button is released, the program in the FLASH memory is faulty. In this case, the phone must be reprogrammed. To do this, we need a UFS programmer with HWK and an f-bus cable to connect the phone to the programmer.

Also we will need a firmware for this phone with the latest version.

We connect the programmer to the computer, install the latest drivers, the latest version of the program for this programmer, perform an update for it (if required). Open the program DCTxBB5, click on the button Connect, so we connect the program with the box (programmer). Next, choose the platform, in our case it’s DCT-4, and select the model you want.

Then click on the Check button to check the cable’s contact with the phone, and also send the loader to the processor. If the processor and flash memory are healthy, then we will see information about this in the program window, if an error is displayed instead of the information, then, probably, we need a replacement or restoration of the processor and / or flash memory mounting.

If the information about the processor and flash memory is displayed, then let’s try to flash the phone. We select in the corresponding windows the firmware files of the main program code (MCU), the language package (PPM), in our case with the Russian language (about the letter “K” at the end of the file name) and the content (CNT) (naturally, also with the Russian language). Versions of MCU, PPM and CNT must match.

Then click the FLASH button to start the firmware process.
If errors occurred during the firmware process, then hardware repair of the processor part and further flashing are necessary.
At the end of the firmware process, we try to turn on our phone. If the result is negative, then hardware repair and more subtle diagnostics are required.

In this article, we talked about the very first steps in the surface diagnostics and repair of telephones. For a deeper diagnosis, additional equipment, electrical circuits, the ability to read and understand them are required.

Battery replacement in iPhone

If the battery life in your iPhone is getting worse, or if it does not hold a charge at all, then you can easily replace the iPhone battery with your own. Before you start, remember that after you open the phone, it will no longer be covered by a warranty.

What will be required to replace the iPhone battery (visit our official website)

During the repair you will need:
– actually iPhone;
– crosshead screwdriver;
– A new battery for your device;
– One special screwdriver (so-called “star”);
– A sharp plastic tool that allows to ensure safe contact with the case of the communicator.

Next, we will discuss the items about replacing the iPhone battery.

1. Turn off the iPhone

Even before the beginning of the repair work to replace the iPhone battery, you must turn off your device.

2. Remove the rear cover

With the help of a screwdriver “star” it is necessary to unscrew the screws and set aside. They are exactly the same, so if you confuse them – it’s okay.

Next, you need to gently move the back cover of the device up with your thumb, slightly pressing it with your thumb. After that, it remains only to remove the back cover and set it aside.

3. Remove the battery and earthing clamp

Using a Phillips screwdriver, you need to unscrew a pair of screws that hold the battery in the casing. These are different cogs, so you need to remember where one of them was. The one that is bigger is the main cog.

Near the first screw you can see a small earthing clamp. You will need to use a sharpened tool to remove the clamp. If you do not do this, the clamp can fly away, after which it will be difficult to find. Using a thin sharp tool, gently lift the connector near the bottom of the battery.

Next, you need to remove the battery from the side of the case, where the volume buttons are located. It should be borne in mind that the battery is fixed with glue. And it can sit tight in the case, so you need to be careful, do not press hard on the edges of the case, and do not bend the battery. If one side remains stationary, it is necessary to try to pick it up in other places, while try not to go too close to the keys or to the power connector.

After you get the old battery, you can move on to installing a new one.

4. Replace the battery and install a grounding clamp

You should pay attention to the way the wires are bent, which is located near the battery connector. If in a new battery it has a different shape or is bent differently, then it is necessary to make it identical to the one that is installed in the old battery. Next, you need to install the grounding clamp you removed earlier.

Then you need to install a new battery in the case, then you need to press it down with moderate force to make sure that it is stuck. After that, you need to twist a couple of screws holding the battery with a Phillips screwdriver. It is absolutely necessary to make sure that the earthing clamp remains in the correct position. It is likely that during the tightening of the top screw you need to hold the clamp so that it does not come off. Then it remains to tighten the main screw.

5. Install the rear cover

To install the back cover when replacing the iPhone battery, you need to attach it so that the hinges can engage with the body and slide it down. The lid should be exactly in place. After the back cover has precisely become in place and is on the same level with the actual body, it remains to screw the two screws on each side with a screwdriver in the form of an asterisk.

Once the iPhone battery is replaced and the device is fully assembled, it can be turned on. If the phone does not activate, you should try to connect it to the charger and see if the battery indication is visible. It’s possible that your new battery is simply dead.

Troubleshooting iPhone | How to fix iPhone

The first and most important is a visual inspection. Take the device in your hands, examine it, are there chips, bends, a whole glass of the display, what is inside the charging connector? Then the most frequent problems that the primary diagnosis reveals:

IPhone does not turn on, there is no reaction to charging: see the lightning port, often there is a millimeter of three stuffed dust, the connector does not come to the end, the phone does not charge, and so on.

It turns on, there is a vibration, there is a welcome sound, but there is no picture; if the display is broken, then everything is clear, if the display is visually intact, but the picture still does not exist, while turning on the phone, look carefully at the center, is there an outline of the apple? If the apple is barely visible, then the problem is with the backlight. Either the backlight driver, or the display backlight.

In the case of the backlight driver (in fact, it can be a backlight diode, or simply a short-circuit of the 25V backlight capacitor), prepare for a not very pleasant BGA soldering hairdryer or infra, if it flies out the backlight on the display, then simply replace him.

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It turns on, does not charge, to replace the bottom cable, if it does not help, put a known good battery and try again, it will not help, change TRISTAR, on iPhone 6 and on, you need to change the tigris (TIGRIS). These operations are also not the most pleasant, you need to work carefully, remove the chips immediately, as soon as you realize that the solder under them swam, do not pull, it is likely to overheat the underside of the board (at 5S under three hundred, for example, a modem, you do not want IMEI is gone after the repair charge).

At this point, you can also include all sorts of suspicious charging modes, charging with too little current or too much, charging with jumps, the iPhone is charged only when turned on. Remember, if the problem with charging, you always need to dig in the direction of TRISTAR and its attendants. Tristar, by the way, is engaged not only in charging, but also in input-output via USB bus and in lightning.

Any problems of non-working accessories.
No sound, no camera, no vibration, or other vital non-essential functions. Most of it is a faulty binding (speakers, vibration, microphones, camera loops, front sensors), change it, if it does not help, open google, a lot of useful information can be obtained on gsmforum, or on the English Internet for iphone 5 no camera solution and pr. Important: do not run jumper over the board, if someone wrote on the Internet just make a jumper, think with your own head before taking the soldering iron into your hands. Finished solyushki from the Internet tend not to work.

The body is a brick. Everything works, except the board
Excellent! You have a full set of spare parts for an iPhone, but seriously, start with the schemes. Schemes for apples are searched here iphone schematic boardview first – PDF files pages per hundred, second – very convenient graphical schemes, click on the item, and the program can tell what it is and what is connected. If you are not superman and do not have x-ray vision, then a boardwire, in general an indispensable thing.

You never know where the next condenser’s leg goes. Before opening the circuit, it is possible for luck to walk through the multimeter-wire through the largest capacitors on the board (MUST DISCONNECT THE POWER BOX BEFORE THIS), find what is ringing; on this line, the closure, open the borderview, the circuit, and look for what could go into the closure. Microcircuits are closed rarely, in all as a rule the condenser is guilty, which you evaporate last.

Make a measurement of the resistance on the main board power lines, write them down, try to turn on the board, apply 4V voltage from the laboratory PSU to the battery contacts, run the board with a USB stick or button.

Pay attention to power consumption. During the load, for example, 5 / 5S / 5C can consume from 200 mA to 900 mA, this is its normal currents. If you saw that there is a huge current somewhere, immediately disconnect the circuit from the power source, feel touch the board for hot items. Prepare pure ethyl alcohol (99%), lower the voltage of the power source to 3V, pour alcohol on one side of the board and apply voltage to it, pay attention to the current, the current in 1A is enough to allow alcohol around the first heated element.

Once you have found the culprit, unplug the power and start replacing. Attention! This method only deals with abnormally heated elements, the phone’s processor can operate at a temperature above the tolerance threshold of a person, it does not need to be soldered
Have you changed the behavior of the board for the better? She began to turn on, but something is wrong? Try to run it until the lock screen appears, tell the client about the successful start and specify if you need to back up the data, always make backups, even if you are sure that everything will go 100% good.

Where can I get schemes for iPhones?
For a deep diagnosis, you need a motherboard circuit, without it you can very long guess the function of the elements and their modes of operation. Where to get the schemes? Schemes for iPhones have long been found on the open spaces of the network, despite the fact that the distribution of schemes is an illegal act. Unfortunately, we can not tell you where exactly you can take the scheme for iPhones.
Is it possible to repair iphone from you?
Yes, you can. We are in Cincinnati, find the address and contacts of our repair shops for iPhones on the contacts page. We do not accept repair of the device by mail (yet), you need a personal presence of the owner of the phone when transferring to repair and receipt.

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The price of diagnostic iPhone
In our service, the diagnosis of iPhone is free in all cases, except for devices that come into contact with water. The fact is that the phones are rather difficult to diagnose and repair after the water. Diagnosis after water means cleaning the device from moisture, its traces, oxides. In fact, to diagnose an iPhone after the water is to do half the work. Therefore, for the diagnosis of drowned people, we take money. The cost can be specified by phone (it varies from the current download of the masters)

Professional repair of Samsung mobile phones


The main types of breakdowns must be known to every user. Self-repair devices can lead to significant financial costs. Re-flashing the phone (for example Samsung) is not a method of restoring the device. The best solution in case of breakdowns of mobile phones is the services of professionals in service centers.

Ordinary users perceive the phone as a sophisticated high-tech device. Therefore, in case of any breakdown, they use the services of workshops that repair phones with a warranty. The service center in Kiev offers low prices for repairing phones of different brands.

Mobile phones are devices that can have both simple breakdowns and more serious ones. In any case, it is recommended to contact only the services of professionals.

Major breakdowns of mobile phones:

moisture ingress;
mechanical damage;
damage to the display;
battery failure;
processor failure;
damage speaker.
In some cases, it is impossible to accurately diagnose and determine the cause of the device failure. For example, the phone does not turn on and has an incorrect functioning. In the absence of visible damage, many users resort to a service such as phone firmware.

Most mobile phone owners prefer to give the phone for a flashing instead of qualitative repair in the service center. Many are absolutely sure that the correct flashing is a guarantee of the phone’s recovery.

Masters-amateurs who offer flashing services according to the instructions, guarantee the restoration and high-quality operation of the phone. On the Internet, there are special portals and themed sites that advertise mobile firmware services.

Users read the information on the Internet and turn to such professionals. However, in many cases, such a procedure does not bring positive results. What can I advise an ordinary user? Trust the professionals who perform high-quality repair of Samsung Galaxy A5 mobile phones with a warranty.

The service center can not always repair the phone. It is important to establish the original cause of the device failure. Re-flashing is done, and the cause of the failure may be in another. For example, as a result of light mechanical influences, the soldering under the microcircuit is broken.

Re-flashing performed by a master craftsman can aggravate the situation. You can not blindly trust the wonders of the Internet. Especially if it concerns the repair of mobile phones. Incorrect firmware can destroy the phone, and minimize the chances of its recovery.

The user is not advised to repair the mobile device on his own. Masters in the centers perform from 10 phone repairs and more. The speed of repair depends on the cause of the failure of the device. On  our official website electronicsrepair.site you can order quality phone repair.

Service centers in Kiev conduct diagnostics and repair of Samsung mobile phones, including Galaxy S6 with a warranty. Come to us and trust the phone professionals!

Broken glass in the iPhone / iPad

iPhone – one of the most popular “apple” devices. It is attractive for its functionality, convenience, reliability and respectable design. For all its advantages, this device, unfortunately, can break. Most often the screen beats. But the case can suffer as well. Even a protective glass and a cover do not help.

Why does the glass break the iPhone?
There are a lot of reasons that cause the iPhone to break glass. But most often the following situations occur:

iphone screen repair

“Apple” device fell on the asphalt, curb, a ladder of stone, etc .;
On the screen inadvertently put a heavy object. From this he just burst;
The glass cracked due to a sharp temperature drop. This usually occurs in winter;
The iPhone hit the dog’s mouth;
The device was in the hands of children who began to throw it like a ball;
The smartphone is operated under extreme conditions.
Broken glass: what to do?
Do not panic. Any malfunction can be eliminated. Broken glass is no exception. Just need to find an intelligent wizard. It will replace both the glass and the display. These two elements are assembled.
This breakage is not a warranty case, so it will not be possible to replace the damaged iPhone with a whole one. However, if you have a desire to get a new device, you should know that a good discount can be provided in the company’s service center.

Preparatory work before changing glass
Before the broken glass of the “apple” device is replaced with a new one, the following manipulations are performed:
1. The screen is removed. It removes the cable, acoustic speaker, frame, button “Home”.
2. The plastic frames are removed, by means of which the display and the body of the device are interlocked.
3. Remove the suspension.

Thinness of glass replacement for iPhone
The fragments are separated from the sensor part by a special device called a separator. The operating temperature is 80 degrees. Then the disassembled screen is connected to the phone and its operability is checked. If it works, then the dried sticker is removed from the display. For this, a special liquid and a scraper are used.
Further on the matrix is ​​applied ultraviolet adhesive. After it spreads a little, a new oleophobic glass is installed on the matrix. At the final stage, the frame is glued and the backlight is installed.

Whom should I entrust to replace the glass?
At first glance, it may seem that replacing the glass in the “apple” smartphone is not difficult. However, in fact, this process has some peculiarities. Each of our master knows them perfectly. Therefore, ask for help specifically to him. It will return your iPhone’s original functionality and luxurious appearance. He has all the equipment, tools and spare parts needed for this.

The glass broke the iPad
The glass installed on the iPad is made using a special technology. It can withstand more than 200 million clicks. However, some users even break this glass.

Why can the glass break in the iPad?
In most cases, the glass in the iPad is broken as a result of the following reasons:
• The “Apple” device fell from a height, it was hit or subject to some other mechanical damage.
• The iPad was heavily deformed. For example, you put it in the back pocket of trousers, forgot about it and sat down on a chair. As a result of such actions, a large transverse crack usually appears.
• Careless handling of the machine. In some cases, the sensor works even when the screen is broken. However, this is extremely inconvenient and ugly.

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What should I do if the glass is broken in the iPad?
If the glass on the iPad crashed, do not get discouraged. This is not the worst thing that could happen with your “apple” apparatus. A similar problem is solved. The main thing is to contact the master, who has all the necessary equipment, tools and original spare parts.

Stages of replacement of glass in iPad
The process of replacing broken glass on the iPad proceeds in several stages:
1. Carefully remove old damaged glass. For this special thermo equipment is used. It is important not to damage the plumes of peripheral components and the antenna of Wi-Fi.
2. The correctness of the device is checked. It is important to know how all buttons work, the camera, whether there is a sound, an image, etc.
3. The inside of the body is scrupulously cleaned. Remove the old glue and apply a new adhesive layer (around the perimeter of the iPad in places where it contacts the glass).
4. A new glass is put. Compressed air is used. It is thanks to him that it is possible to prevent dust from getting between the glass and the display. To ensure that the new glass adheres well to the body, heat treatment is carried out.

If the housing is damaged
If the case of the iPad is damaged (dents or chips in the places where the glass is attached), then before the glass is replaced, the device is completely disassembled and the metal body is straightened. If you do not perform this manipulation, then the new glass will not “stand” in the case.