As Woland once said: “The trouble is not that a person is mortal, but that he is suddenly mortal.” The same can be said about our electronic friends - smartphones and tablets. Just half an hour ago it was mysteriously flickering on the screen and pumping bass in the headphones, but now it lies black, cold and does not react in any way to your attempts to revive it: it does not turn on, does not charge. The same problem can occur when purchasing a used device. And devices purchased at promotional prices on sales can unpleasantly surprise the owner. Why a smartphone goes into a deep coma and how to get it out of this state is the topic of our short instructions on providing emergency care.
Why doesn't the device turn on?
The problem of a device showing no signs of life is perhaps the most common problem in the world of digital gadgets. As with most emergency situations, a correct diagnosis is 99% successful.
The smartphone or tablet may not turn on due to software problems, hardware failures or malfunctions battery. The reasons why the device does not turn on are a carriage and a small cart.
Charger fault
Chargers are compact, operate in severe thermal conditions and therefore often fail. The most correct way to check is to use a voltmeter to make sure that there is a constant voltage of 5 V at the output of the power supply. If this is not possible, you need to connect another working smartphone to this power supply and check if charging is taking place.
USB cable damage
Cables fail much more often than power supplies. The wire becomes kinked and the charging plug becomes loose when connected/disconnected multiple times. At some point, the electrical contact is broken and current no longer flows through the cable. No current - no charging. The cable is tested by connecting it to a known-good power supply and a working smartphone.
Battery deep discharge
The problem of deep discharge is typical for devices that have been left for a long time without use/charging or have been in storage. The reason is that even when the smartphone is turned off, the battery is discharged due to self-discharge and current consumption by standby circuits. The operating voltage of a lithium-polymer battery is 3.6–3.7 V. If the battery voltage drops below 3.2 V, the smartphone charge controller will not be able to charge it due to the operating algorithm. To verify the problem of deep discharge, you need to remove the battery from the device and connect it to a voltmeter.
Battery failure
The original battery is designed for approximately 500 charge/discharge cycles. During its service life, its capacity decreases. At one point, the battery capacity becomes so small that it can no longer be charged. Such a malfunction is easily monitored, since as the battery capacity decreases, the operating time of the device also decreases.
As a separate item, we will consider battery failure due to overheating. Most often, this affects unpackaged lithium-polymer batteries in tablets and some smartphones with a non-removable battery. Due to the high temperature, gas formation begins in a sealed battery and it swells. If it is not replaced in time, the consequences can be dire.
If the battery loses its seal, it will catch fire or explode; in addition, by increasing in size due to gases, the battery can damage the inside of the smartphone. Screens and sensors crushed from the inside are not uncommon.
Malfunction of the charge controller in a smartphone or tablet
Part electronic circuit smartphone is designed to charge the battery when connected network device. The charge controller monitors the remaining battery capacity, charges it when the level is low and stops charging when it reaches 100%. If you connect a non-original charger, a short-circuited cable, or a power surge, the charge controller may be damaged. After this, the smartphone will not be able to charge the battery, although it will work fine from a charged battery or from a power supply.
Repairing the power controller on a tablet board is not a cheap pleasure. If your device is older, it would be more advisable to power it via the Micro-USB port using external battery(PowerBank), as repairs may exceed your pet's resale value.
Troubleshooting power issues
The mains charger and cable have been checked. Now we know for sure that the problem is in the device. Our first task is to try to charge the battery.
If the smartphone’s battery is removable, a charger, popularly called a “Frog,” will help us.
Connect the battery to the Frog and charge for 2-3 hours. Then install it back into your smartphone. If the smartphone starts up, connect its original charger and monitor the charge. Does not charge - the charge controller is faulty. You happily walk with the device to the service center.
If the battery is deeply discharged, the algorithm of actions will be somewhat more complicated. If you do not know how to hold a soldering iron in your hands, it is better to contact a service center or buy a new battery. Are you determined to do everything yourself? Let's get started:
Video: how to charge the battery using the Frog
The device starts downloading, but does not complete it
Your electronic friend turns on, displays the splash screen and even begins to boot. Then it goes out and everything repeats again. This malfunction can have two causes: software and hardware.
There can be many reasons for a software failure: viruses and damaged file system user section, and thoughtless use of serious system utilities. The fix algorithm is simple - boot the smartphone into Recovery mode and reset to factory settings:
A hardware failure could be that the battery controller has locked it at, say, 10-15% charge. The smartphone sees when loading low level charge and turns off. The treatment recipe is the same as in the case of a deep battery discharge: remove the battery, unsolder the controller from the “can”, charge the can with a charger to 3.7–4 V. But this solution is palliative. A battery that has gone through a deep discharge has already irreversibly lost a fair portion of its capacity. The best solution I will buy a new battery if possible.
The smartphone vibrates but does not turn on
If the smartphone vibrates but does not boot, this indicates that the battery is discharged to 0%. In this state, the smartphone will not be able to charge the battery on its own. It must be removed and charged using a universal charger, as described above. When removing the battery, assess its condition. If there are signs of swelling or loss of tightness, be sure to replace it.
Don't charge universal charging the battery lasts longer than 1.5–2 hours - this can damage the battery, because temperature control and overcharge protection universal device No.
The smartphone does not turn on after firmware or update
The firmware was unsuccessful. Was it software glitch or the battery goes out in the middle of the process - it doesn’t matter anymore. You need to put your smartphone into emergency (download) mode, repeat the firmware process or restore it. All user data will most likely be lost. Let's consider this operation using the example of a Samsung Galaxy smartphone:
- Switch your smartphone to Download mode: simultaneously press the power button, volume up and the center key.
- Connect your smartphone with a cable to USB port the computer on which you run Samsung program Kies.
- Go to the Tools tab and then select Disaster recovery firmware".
- Select your smartphone from the list. If it is not displayed, you will not be able to restore it using this method.
- Enter the emergency recovery code.
- Click the "Restore" button.
The device is charging but does not turn on
In this case, there may be several reasons:
Of course, buying new smartphone, you need to check it thoroughly in the store. But when shopping on online platforms, this may not be possible. And returning a problematic unit is often not easy. The fact is that a new smartphone can lie in a warehouse for many months, all this time its battery is discharged and may well reach such a lower threshold when it is blocked by the charge controller.
The first step is to connect the smartphone to its factory charger and allow it to charge for 7–9 hours. If this does not help, follow the algorithm for working with a deep-discharge battery: remove the battery and try charging it with a universal “Frog” charger. If this charging mode, as well as charging the “can” bypassing the controller, did not help, the only option left is to replace the battery with a new one.
Buttons, sockets and contacts
Let us briefly mention several common mechanical failures:
- The power button on the smartphone is broken. Of all the buttons, it is pressed most often, since it also serves as a screen blanking button. Its resource is not infinite, and at some point it breaks. And without a power button, you cannot turn on your smartphone. This is such a tautology;
- The USB socket in the smartphone is broken. By carelessly connecting and disconnecting the cable, you can damage not only it, but also the USB socket in the smartphone itself. And if you can simply buy a new cable, then the socket will have to be changed by service center specialists;
- The battery connection contacts are oxidized. Most often, this problem occurs after “bathing”, when the smartphone gets into liquid. You can try to clean the contacts yourself using a medium-hard eraser, but it is better to contact a service center, because the liquid has penetrated much deeper than the battery connector.
Video: what to do if your phone freezes or won’t turn on
Prevention is cheaper than repair
To prevent your pet from getting caught operating table to service engineers, but your wallet has not become noticeably lighter, you should follow a number of simple rules:
- Charge your smartphone only with an original charger and original cable;
- carefully connect the charging cable to the device, avoiding side loads on the socket;
- Once every one and a half to two months, inspect the battery for damage and swelling;
- do not drop your smartphone and keep it away from water;
- Avoid heating the device too much, do not leave your smartphone in the open sun.
If your device won't turn on or won't charge, the first step is to try to find the problem yourself and fix it. And although some malfunctions are guaranteed to make you a customer of the service center, simple reasons will allow you to get by with simple ones. inexpensive solutions, protecting your wallet and boosting your self-esteem.
And then my thoughts immediately run wild. The fact is that the cause of this malfunction can be something as small as a dead phone battery, or very serious damage to both the software and the phone board. Or even damage that is generally incompatible with repairability. Diagnosis of this malfunction can be either easy or very labor-intensive and extensive. Each master has his own algorithm (sequence) for carrying out inspection operations and control measurements. Someone immediately gets into the weeds (for example, fill the entire board with flux and solder all the chips, or immediately start flashing the phone). The main thing is to understand how to distinguish software faults from hardware ones.
Any diagnostics must begin with checking the power source. If you plan to turn on the phone for testing using a standard battery, you need to measure the charge level. It must be at least 3.6V. If the battery is discharged, it must be charged to the required level using the standard method (if the current state of the phone allows it) or using a universal charger. It is preferable to use a power supply to power the phone, which provides an output voltage of at least 4V with an indicator of current consumption. Read more about choosing PSU and Universal Charger discussed in the equipment and materials section.
Having set the required power supply voltage, observing polarity, connect the alligator clips to the contact terminals of the phone battery:
Without pressing the power button, we immediately look at the ammeter arrow of the power supply. If it stands inviolably at the initial (zero) position or deviates slightly and immediately returns to its original position (the process of charging the capacitors to power the phone has occurred), then everything is in order in the primary power supply circuits of the phone. This means that there is no short circuit and increased consumption when it is turned off and you can try to turn on the phone with the power button.
If the ammeter needle deviates noticeably and shows not very high consumption (tens of milliamps), this most often indicates that moisture has gotten inside the phone. Moreover, this does not necessarily mean complete or partial flooding of the phone with liquid. Sometimes it's enough to talk on the phone during the rain or pick up the phone with wet hands. Read more about diagnosing phones after exposure to moisture.
In the case of high consumption (hundreds of milliamps, and more often 0.5 Amps and higher - up to the maximum possible) - a clear sign of a short circuit in the primary power circuits (battery circuits). As a rule, with such consumption, the “culprit” immediately heats up to a high temperature (you can barely hold your finger or not hold it at all). This fact helps to find the fault well. In 99% of cases, it is the faulty element that heats up. ATTENTION! Such a high percentage is typical for elements in the primary power supply circuits. There are other features for elements in secondary power circuits!
In the primary, as a rule, GSM Power Amplifiers, power controllers, power converters (just for secondary power circuits), power converters for the display and keyboard backlight, power converters for memory cards, cameras, audio power amplifiers, separate battery charge controllers and separate capacitors parallel to the power supply. According to my statistics, all of the listed elements, except for the GSM power amplifier, in 90% of cases fail again due to exposure to moisture! As for amplifiers, they like to short out after the phone falls and hits. It is much less common.
If the ammeter readings are normal, press the power button and look at the consumption again.
It should be remembered that in order to normally turn on NOKIA brand phones from the power supply, you need to connect the middle contact of the battery connector to the negative one (look at the photo above!).
Under normal conditions, switching occurs with the simultaneous execution of several operations (starting secondary power supplies, initializing and executing software, self-test, etc.). In this case, the ammeter readings fluctuate very quickly within the range of 30 - 50 mA, until the phone’s backlight and other modules are activated. Consumption increases to 100 - 300mA (for different phones differently; mainly for phones with large diagonal color displays). As soon as the phone is registered on the network, the consumption can briefly increase to 400mA. Read more about current consumption in different modes.
We press the power button, but there is no result - the ammeter needle stands still. There are several reasons:
1. The power button is faulty. We find the power button on the phone board and, depending on its design, proceed as follows:
If the button is made separately from the rest of the keyboard and, as a rule, is placed on the top or side edge of the phone and has a body of this type
Then we check the functionality of the button by pressing and simultaneously measuring the resistance. It happens that over time, the internal contacts of the button oxidize or wear out and, accordingly, such a button, when pressed, gives a lot of resistance instead of a good closure. If the button is normal, check the quality of soldering contact pins on the board. Sometimes a soldering failure is visible to the naked eye, and sometimes there are invisible microcracks that instantly oxidize and contact is almost impossible;
If the button is located on the general matrix of the keyboard under an elastic adhesive film that holds springy steel plates - membranes (round or elongated) strictly in place
then carefully peel off the film with the buttons and examine the surface of the contact pads of the button on the board and the steel round membranes for the presence of oxides. If there are any, they must be removed. It is best to do this with an eraser - a pencil with a brush or a regular eraser.
2. The power button circuits are faulty. The phone's power button is most often connected to the power controller through the interlayer connections of the board. Often these circuits contain discrete elements (resistors, varistors, capacitors), which are located in close proximity to the power button, although the exact location must be looked at in the diagram. If the track that connects the power button to the power controller is broken, the phone will not turn on. This mainly happens when the phone falls. At the moment of impact, the board and all elements of the phone experience severe overload. Soldering failure occurs, especially on large BGA chips. In such cases, soldering these chips or complete dismantling with rolling (reballing) of the leads and subsequent installation helps. Sometimes impacts are accompanied by breaks in contact pads and board tracks. In such cases, the board should be replaced with a new one.
As for discrete elements. If there is a resistor in series in the switching circuit, it is worth checking its presence and the integrity of the soldering. Sometimes they come off at the moment of impact, but most often they are torn off by the users themselves when they begin to press the power button with passion and it certainly comes off and demolishes everything in its path. Or the torn button falls out of the phone body and “advanced” users begin to turn on the phone by shorting the contact pads using improvised means (the tip of a knife, scissors, etc.). Accordingly, both the elements and the board suffer.
In addition to resistors, varistors and capacitors are common culprits. Only when they malfunction, another, completely opposite defect appears - the phone turns on itself when power is applied or as soon as the battery is inserted, since the varistor and capacitor are parallel to the power button. When moisture gets into the phone, these elements (especially the varistor) begin to shorten. The phone perceives this as a button press.
Don't forget about phones - flip phones, sliders and the like. If the power button is not on the main board, the fault may be the same inter-board cable. This defect occurs quite often and can be eliminated by replacing the cable.
Checking the power button circuits is done by checking the continuity tester or by measuring the voltage at the contacts of the power button. With a working gearbox, the voltage of the power button of the majority cell phones is about 4V. For Siemens phones of the C65, CX65 series and similar ones, the power button voltage is about 1.95V.
3. The power controller is faulty or its soldering is faulty. Gearbox failure is a fairly rare occurrence. Usually in such cases, consumption, on the contrary, is very high and is accompanied by characteristic heating of the chip. Soldering failures are much more common. As mentioned above, soldering or rolling the BGA chip helps.
If there is voltage at the power button, but there is no response to pressing it, you should use an oscilloscope to check the generation of the clock generator built into the power controller (or processor) with a frequency of 32 kHz. The diagram shows this:
On the phone board, the quartz resonator looks like this:
The case design of quartz can be varied. In addition to what is shown in the photo, phones also contain:
These elements are quite fragile and, when the phone is dropped, are often destroyed, although outwardly they look absolutely intact.
Having set the appropriate parameters of the oscilloscope (TIME/DIV. = 20uS, V/DIV. = 500mV), we measure the generation. We should see the following signal on the oscilloscope screen:
If this signal is absent, it can be assumed that the quartz resonator is faulty and must be replaced. However, before replacing, you need to make sure that there is a constant supply voltage to the quartz, usually 0.3 - 0.5V. Otherwise, you need to solder/replace the power controller (processor).
4. Secondary power supplies are faulty- power supply for processor, memory and other equipment. devices. In more simple phones supply voltage data (2.8V, 1.8, etc.) are implemented using the same power controller. In more complex ones (smartphones), with several processors and types of memory, as well as a variety of built-in devices, secondary power supplies are made in the form of separate (most often pulsed) DC/DC converters. The most common failure is failure due to moisture. Less often - impacts and short circuits. They are checked by careful visual inspection and measurement of the corresponding voltages according to the diagram.
Examples of secondary power supplies:
These fragments of the circuits indicate the input voltage VBAT (phone battery supply voltage) and the output voltage - VCORE, VDDR_APE, VIO.
5. Software problems mobile phone . If, when you press the power button, the phone's consumption increases to 20 - 30 mA and immediately drops and no further action occurs, then we can assume that the malfunction lies in a malfunction of the phone's software. This fact is carefully verified by testing or restoring the software using a programmer.
A very common defect cell phones and other digital mobile devices"does not turn on" Note that this is the most insidious defect, which does not allow us to immediately objectively assess the prospects for restoring a device that does not turn on.
The device may not turn on due to a discharged battery, but if you still tried to charge the device and it did not give the desired result, then the problem is most likely a fault in the power circuit. Of course, in this case, the malfunction can be caused by a number of other reasons.
Most often this malfunction is caused by a failure power controller– a microcircuit responsible for the distribution and consumption of power. Most often, the controller is a BGA chip, which is a key element of a digital device.
Reasons for failure of the power controller
This problem is most often a consequence of mechanical damage. There are also options for its failure due to liquid getting inside the product. In any of these cases, replacement of this component is required. Replacing a BGA chip is a complex and responsible process that is beyond the power of amateurs. It is worth especially noting that the professionalism of the person changing cell phone power controller or any other digital device, the further performance of the device directly depends. This process requires not only professionalism and endurance, but also enormous practical skills in replacing BGA chips.
Repair of power controllers
This technological operation is performed by highly qualified service engineers. You will receive a quality guarantee for the work performed and components replaced, which will allow you to evaluate the quality of the work performed and test your device in everyday use.
Know that a service center that carries out hardware repairs at the level of replacing and re-rolling BGA chips is worthy of sincere respect. For example, in authorized (branded) service centers they try not to carry out this type of repair, changing it if necessary motherboards entire devices.
Parts 1 and 2 relate to RF and here it is much more difficult to identify common features for all phone models, but something can be done. So, if we consider part of the board 2 (Fig. 3), then here, as a rule, there is an RF controller chip (1), which is responsible for the frequencies in the telephone, as well as a master quartz resonator 2 (13 or 26 MHz) and a controlled oscillator voltage 3. In part 1 (Fig. 4) we can highlight operational amplifier (OP-Amp) 1, which amplifies the phone signal and transmits it through the antenna switch 2 to the emitter (antenna). Ceramic filters 3 and 4 are 900 and 1800 MHz filters. Of course, this scheme is very simplified, but to find 50% of the faults that occur in the phone, this is quite enough. More details below
The phone does not turn on:
Power chain:
1) Troubleshooting should begin by checking the battery. The voltage at the battery terminals should not be less than its nominal value of 3.6V, otherwise the power controller (Power Supply IC) considers the battery to be faulty or does not respond to it at all . If everything is in order with the battery, then it is further recommended to connect from an external regulated source via a milliammeter. It should be noted that Nokia phones will not turn on normally with such a circuit, you will have to supply logical signals to additional power terminals (either 0 V or the supply voltage through a resistor with a resistance of 1...10 kOhm). the main task such a connection, measure the current consumption of the phone when turned on.
The following options are possible:
When turned on, the phone's current consumption is zero. This is the simplest case. Most likely the power circuit fuse has blown (you need to look for it by specific
diagram), or the power button has failed (easy to check with a tester), or the power controller has failed (2). It is also possible that the conductive paths are broken, for example, from the power button to the power controller. In any case, all these faults are easy to identify and correct.
When you turn on the power it goes very high current, for example, about 1 A. In this case, it is necessary to determine what will heat up on the board. As a rule, the heating element will be defective. However, some rules need to be highlighted: firstly, if a large current flows immediately after turning on the power and at the same time microcircuit 2 heats up (Fig. 2), then it definitely needs to be changed; secondly, if the current starts flowing only after pressing the power button and the same microcircuit heats up, then it most likely has nothing to do with it. Let me remind you that chip 2 is a power controller and it can get warm if
Any other microcircuit that is powered through the controller is defective. I can suggest the following way to find a faulty microcircuit: use a tester to check the resistance on the secondary power capacitors. Most likely, one of the capacitors will have a resistance of about 0 ohms. If you don’t have a circuit diagram for this phone model at hand, you will have to unsolder chip 2 from the board (so as not to damage it with further actions) and apply an external voltage of about 3 V to the suspicious capacitor from the power supply, observing the polarity, and again evaluate the temperature of the chips on the board. A hot chip will already be 100% defective.
When turned on, a current of about 10-20 mA flows. In this case, the phone's operating program in the FLASH chip is most likely damaged.
2) We begin the test in diode continuity mode using a tester (see.NET 2) yellow capacitors. If the plus and minus of the capacitors ring, then we check the chain: one end of the tester is always on the + terminal. (See!!! in NET 2). On the plus we measure for the plus - one plus on the battery, and the second on the capacitor. Should ring on the edge of the resistor R 22, then ring all capacitors from 1 to 6 in turn (see diagram). If it doesn't ring - straight from!!! we forward the MGTF postings (from the part from which it does not ring).
If everything is in order with the track, we apply voltage from the power supply to the capacitor instead of the battery. We measure the voltage on the upper leg of the power button (see. NET 2). Should be 3.6 V . When you press the button, the voltage should drop to zero. If this does not happen, you need to change the power button.
Attention:The power button must not be soldered with flux! The flux gets inside, the button begins to live its own life, the phone begins to turn on by itself.
If there is no voltage on the button, but there is voltage on the other side of the board, then this means that the adapter sleeve is rotten. In this case, we pass the wire through and solder it on both sides.
If the voltage still does not appear on the button, then measure on the capacitor - 3.8 V (see NET) - measure on the left, because right part- on the ground". If there is voltage on the capacitor, but not on the button, then solder the CCONT (Power Supply IC) chip (see NET). If this does not help, you need to change this microcircuit.
If voltage appears on the button, measure points 1, 2, 3. When you press the power button, 2.5 V should appear and disappear at these 3 points (before this, solder the Power Supply). If voltage appears and remains on all three, you need to program the Eeprom. If it appears and remains on the top right, you need to program Flash. If the reason is an electrical fault, the phone will not turn on.
When turned on, a small current of about 1-3 mA flows. This indicates that the power controller is working, but not
The RF controller is working (chip 1 Fig. 3) or the ceramic plates are broken quartz resonator 2 (Fig. 3). Replacing these components usually results in positive result.
After turning off, it turns on only after the battery is juddered: Warm up/Replace CCONT.
Charging is in progress, but does not turn on: If there is no voltage at the power button, then
warm up/replace CCONT. If there is voltage at the button, change V202 (see figure).
Phone won't charge:
For charging device, see NET.
The plus goes to the fuse, then to the coil, the coil should ring at 0, from the coil down to the Charging Control IC, and then to resistor 3 (R22). The tester should ring the fuse and coil. The reading should be 0. Otherwise, the fuse and coil must be replaced.
When charging is connected (the phone is turned off), the charging indicator blinks, when the phone is turned on, the message “not charging” appears: clean the battery contacts and check the transistor and resistor near the contacts.
Constant charging: Warm up/Replace CCONT.
3310 Not charging: Check F200 (see picture).
"Not charging" with Li-ion battery, Ni-MH - everything is fine: software reset.
Rapid battery drain when making a call: Warm up/Replace CCONT, change PA.
"reconect charger": 1. Place jumper R204 - R200 (see figure); 2. Warm up/Replace CCONT.
8210 "Not charging": Remove V 100 (see picture).
8210 Does not respond to charging:Check F101 (see picture).
8210 Charging is in progress, but does not turn on:If there is no voltage at the power button, then warm up/replace CCONT. If there is voltage at the button, change V116 (see figure).
8310, 6510 Does not respond to charging: Check F100 (see picture).
Attention: In Nokia interchangeable chips inside the platform DCT 3 (3210, 3310, 3410, 6151, 8210, 8850, 2110, 6110, 5110, 5210, 5510, almost all models before 2000). The same is true for platform models DCT 4 (3510, 65**, 72**, etc.) Exception – 8310, 7650.
Net
The most common hardware defect is the failure of the "antenna switch", usually this is manifested by the absence of a network, or the inability to obtain registration in the network, as well as the floating of the network voltage indicator. The ceramic substrate of the antenna switch (as well as the transmitter) is very fragile and when the phone is dropped, it is these elements that most often fail. Diagnostic methods are shown in the figures.
The above solution can only be used to diagnose functionality of this node, because The phone only works in the 900 MHz band.
In order to determine the reason for the lack of network, you need to go to the Settings menu - Network selection - Manually. If the message “No available networks found” pops up. This means that the phone has no reception, there is a problem with the receiver. If available networks are detected, the transmitter does not work.
Malfunctions associated with the inability of the phone to work correctly on the network. These faults can be divided into three types:
The phone shows the network level, but when I try to make a call it says something like “call ended.” The most common cause of such a malfunction is that the operational amplifier 1 fig. does not work. 4. In most models, this amplifier is part
circuits on a ceramic substrate and if phones fall, this substrate can very easily break. Therefore, before looking for something more complex, it makes sense to unsolder the operational amplifier from the board and visually assess the integrity of the substrate. Second
the reason is a broken antenna switch 2 Fig. 4. It is also assembled on a ceramic substrate, but is much smaller in size than an operational amplifier, and therefore breaks much less often. It is tested in the same way as an operational amplifier. If replacing these components does not lead to a positive result, then it is necessary to change microcircuit 1 Fig. 2. Let me remind you that this chip is responsible for exchanging phone data with base station. RF controller 1 chip may also fail
Fig.4. For different models phones, the probability of failure of the listed components is different. There are models where you need to start troubleshooting, for example, from the RF controller.
The phone cannot find the network at all. In this case, troubleshooting must begin by checking the antenna and antenna socket Fig. 1. Broken connector external antenna may also be the reason for the missing network layer. If the simplest reasons have been exhausted, then we can then consider the failure of microcircuit 1 in Fig. 1, the loss of parameters of the quartz resonator and generator 3 in Fig. 4, and check whether filters 3 and 4 in Fig. 3 are working.
Jumping network indicator/No network: Change cobba, ccont, pa, change the 1st and 2nd IF filters. Network loss, slow playback of melodies: Replace 32KHz quartz.
The phone shows a low network level or the network periodically disappears. Troubleshooting in this case is practically no different from the case described above.
No network: HAGAR, c508, L511(delete), PA (N702).
8210 No network when infrared port is active: replace C153 (see figure).
Repairs should begin by checking the speaker, microphone or vibration alert, respectively. Then sequentially check the contacts of these parts with the board and the integrity of the conductive paths to the amplifier switches or control chip and, finally, the operability of the chip itself. This type of fault is best considered specific models phones.
Display:
There are lines on the display, or missing lines, etc.: Replace C409 and C410 (see picture).
No call:
Broken track on the board (see picture).
Audio Distortion (RX):
Warm up / Replace COBBA.
Incorrect button recognition: Change R414 and/or R415.
8310, 6510 One or more buttons do not work:
Replace Z301 (see picture).
"Insert Sim": Clean/change SIM card contacts, warm up/replace CCONT.
Battery drain in standby mode less than 1 day: replace PA (N702). : Remove L511 (see illustration).
Spontaneous shutdown (irregular):
1. Shutdown when finding a network: "Reset Software".
2. Without SIM it works, with SIM it turns off when a network is found: Replace PA.
3. Check the battery contacts, check the battery contacts on the board.
4. Random shutdown: remove L511.
5. Random shutdown: change R301.
Addition:
If Nokia 7370, 3650 (with camera), 7650, 6100 is stuck due to memory overflow (i.e. when you turn it on, only Nokia writes), when turning it on, you need to dial *#7370# before Nokia appears. The phone will turn off, then turn on, and will work, however, everything that the user entered will disappear.
The power controller is one of the important microcircuits of any phone, without which you simply cannot turn on the device. Regardless of the complexity of the breakdown, it is not recommended to carry out repair work yourself; it is best to contact a specialized workshop. The Re:Store service center has been replacing phone power controllers since 2009. All work is carried out by highly qualified professionals with a guarantee for a period of 1 to 6 months. Don't know who to turn to for help? Our service center is the best choice!
The main reasons for the failure of the power controller:
- Mechanical damage to integrity as a result of falls and impacts.
- Incorrect operation.
- Liquid and dirt getting inside the device, increased humidity.
- Voltage drop in the network.
- Using non-original power supplies.
Signs that urgent repair of the phone power controller is needed:
- The smartphone is not charging.
- Automatic shutdown or reboot of the device.
- Liquid, dirt, or dust getting inside the smartphone.
- The computer does not detect the phone when connected.
- The device does not turn on.
Is it possible to determine the problem yourself?
If you do not have a special tool, you do not have professional skills and experience in repairs mobile technology, then the chance to determine the real cause of the breakdown is reduced to a minimum. In 60% of cases, Re:Store service center clients tried to disassemble the device themselves in order to find out the cause of the malfunction. This method of solving the problem is incorrect and very dangerous, because you risk aggravating the situation, which will greatly complicate its further repair.
The sequence of replacing the smartphone power controller
- You provide the device to one of the branches of our service center.
- Hardware and software diagnostics are carried out to determine smartphone malfunctions.
- The manager agrees with you on the cost and timing of the repair.
- We are replacing the power controller.
- We inform you when your smartphone is ready via SMS message.
- You pick up the finished device along with the sales receipt and warranty card.
Advantages of the Re:Store service center:
Our service center is equipped with modern professional equipment that will allow us to carry out repair work of any level of complexity. Free diagnostics will identify any type of malfunction, technical or software. You haven't decided yet service center? By contacting us, we can restore functionality and attractiveness. appearance Your device. You can submit a repair request by calling any of the numbers listed on our website.
- Our service center technicians have extensive experience and practical skills in restoring the functionality of smartphones.
- We give preference to modern equipment.
- Minimum deadlines for completing assigned tasks. In 80% of cases, we complete restoration work in just 1-2 days!
- 100% guarantee of the quality of work performed and components.
- Service mobile devices various models, regardless of the complexity of the situation.
- Free diagnostics.
- Availability of courier delivery.
- Restoration work is carried out in strict accordance with the regulations of the manufacturing companies.
- Lowest prices and optimal pricing policy!
Equipment: mounting hair dryer, digital oscilloscope, meters, tweezers, plastic spatula, trinocular microscope, set of professional screwdrivers, Soldering Station, laboratory block nutrition.
Accessories: original spare parts, as well as their high-quality analogues.
Dates: 2-3 days (depending on the complexity of the breakdown and the features of the model).
Guarantee: 6 months.
Prices for repairing a phone power controller are presented in the table:
*These are approximate prices; to find out the exact cost of repairs, please select your phone model in top menu site
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