A mobile phone or other device that uses a charger to charge its battery. The main reasons why failure may occur charger the following:
Broken wire;
Failure of the charging unit;
Broken contact connection between the wire and the plug or charging unit.
Very often, the cause of failure of the charger is a break in the wire or a violation of the contact of the wire with the structural elements of the charger - the plug and the block. In this case, you can repair the charger yourself. Let's consider the principle of eliminating damage to the charger wire using a specific example of repairing a charger mobile phone Nokia (with thin plug).
To repair the charger we will need:
Multimeter;
Soldering iron and everything needed for soldering;
If the device shows a voltage value, this indicates that the charging unit and wire are not damaged. In this case, the device showed 7 volts - this is the nominal output voltage of this charger. On at this stage we can conclude that the charger does not work due to poor contact between the conductors at the point where they are connected to the plug. You can verify this by ringing the plug with the device.
To do this, which come from the plug, insert a thin wire into the inside of the plug (this is necessary for contact with the inner contact part of the plug).
Take a multimeter and select the dialing mode. With one probe we touch one of the stripped conductors, and with the other, first to the outer contact part of the plug, and then to the inserted wire. If the device shows a contact (presence of a sound signal), this indicates that the contact between this wire and the plug is not broken.
We move the probe of the device to another stripped conductor, with the other we touch the outer part of the plug, and then the wire. If, when you touched both contact parts of the plug, the device did not emit a signal, then there is no contact. That is, one of the wires is torn off from the plug.
In this case, there are two ways: you can purchase a new plug, or you can repair the old one. The first method is simpler and more reliable. A new plug can be purchased at mobile phone repair shops or at the radio market. You may have an old charger that does not have a damaged plug.
In this case, it is enough to solder the new plug to the charger, while observing the polarity. How to check if the wires are connected correctly (polarity)? As a rule, each cord has a. If it does not match, then you need to make sure the wires are connected correctly.
To do this, plug the charger into a power socket and the new plug into your mobile phone. Connect the plug leads to the charger cord. If charging has started, then you have connected the conductors correctly. If the phone is not charging, swap the wires. The check must be performed in any case, even if the color markings of the connected cords are the same, since the markings of the cords may not match.
The next step is connecting the two cords. If you have heat shrink tubing, place part of it on one of the cords to be soldered before soldering. Solder the conductors, observing polarity. Insulate both wires with insulating tape and put on heat shrink tubing. Check the functionality of the charger.
If you do not have the opportunity to purchase a new plug, but still want to restore the charger, then the second method of eliminating the damage will suit you - repairing the plug.
Remove the rubber (plastic) covering from the plug with a knife. In this case, be careful, do not rush, as you can damage the plug itself.
The next step is to solder the charging cord to the plug.
We check the functionality of the charger. If everything is normal, insulate the conductors and put a heat-shrinkable tube on the plug. The charger is ready for use.
We examined the case of contact failure at the point where the cord is connected to the plug. There may also be another reason. Let's consider one more case.
You cut the wire, checked for voltage at the output of the charger, there is none. We cut the wire near the charger, moving 7-10 cm away from the charger block. We strip the wire that comes out of the charger block and check for the presence of voltage at the output. The presence of voltage at the output indicates that the charger is working properly. We ring the plug using the above method. In this case there is no contact failure.
Testing the charging cord showed that one of the conductors was broken. No damage is visible visually. The best option is to purchase a new wire. Then solder it to the plug and the charger block, observing the polarity.
To avoid mistakes (especially if the wires have the same color code), before soldering the wires, connect them and plug the charger plug into the phone. If charging has started, connect the conductors by soldering. Insulate the wires at the soldering site and put on a heat-shrinkable tube (it must be put on the wire before soldering). The damage has been repaired.
If the wire is intact and the contact connection of the plug is not broken, then the charging unit is damaged or one of the wires inside the unit is torn off.
Unscrew the charger unit and look at the wire connections. If all the wires are connected normally, then the memory unit itself is damaged.
If your charger unit is damaged, then, without having any skills in electrical engineering, you will not be able to find the reason for its failure, much less eliminate it yourself. Repairing the charger in a specialized service will cost you more than a new charger.
As a rule, repairing such an inexpensive device is not economically profitable.
Especially in non-poor countries. average price 5 dollars.
But it happens that there is no extra money, but there is time and spare parts.
There is no store nearby. Circumstances do not allow. Then it's not about price.
In my case, everything was simple - one of my two chargers broke Nokia AC-3E, friends brought a bag of broken chargers. Among them were a dozen branded Nokia chargers. It was a sin not to take it.
The search for the circuit did not lead to anything, so I took a similar one and converted it to the AC-3E. Many chargers for mobile phones are made using a similar scheme. As a rule, the difference is insignificant. Sometimes the denominations are changed, a little more or a little less elements, sometimes a charge indication is added. But basically the same thing.
That's why this description and the diagram will be useful for repairing not only the AC-3E.
The repair instructions are simple and written for non-specialists.
The scheme is clickable and of good quality. 
THEORY.
The device is a blocking oscillator operating in a self-oscillating mode. It is powered by a half-wave rectifier (D1, C1) with a voltage of approximately +300 V. Resistor R1, R2 limits the starting current of the device and acts as a fuse. The blocking oscillator is based on a transistor MJE13005 and a pulse transformer. A necessary element of the blocking generator is a positive circuit Feedback formed by winding 2 of the transformer, elements R5, R4 C2.
The 5v6 zener diode limits the voltage at the base of the MJE13005 transistor to within five volts.
Damper circuit D3, C4, R6 limits voltage surges on winding 1 of the transformer. At the moment the transistor is turned off, these surges can exceed the supply voltage several times, so the minimum permissible voltage of capacitor C4 and diode D3 must be no lower than 1 kV.
PRACTICE.
1. Disassembly. Self-tapping screws holding the charger cover in this device They look like a triangular star. As a rule, there is no special screwdriver at hand, so you have to get out as best you can. I unscrewed it with a screwdriver, which, over the course of its use, had become sharpened into all sorts of crosses.
Sometimes chargers are assembled without bolts. In this case, the body halves are glued together. This indicates the low cost and quality of the device. Disassembling such a memory is a little more difficult. You need to split the body with a non-sharp screwdriver, gently pressing on the joint of the halves.
2. External inspection of the board. More than 50% of defects can be detected through external inspection. Burnt resistors and a darkened board will show you the location of the defect. A burst case or cracks on the board will indicate that the device was dropped. Chargers are used in extreme conditions, so falls from anywhere are a common cause of failure.
In five out of ten memory systems that I had the opportunity to do, they were trivial contacts bent through which 220 volts are supplied to the board.
To fix it, just slightly bend the contacts towards the board.
You can check whether the contacts are at fault or not by soldering the power cord to the board and measuring the voltage at the output - the red and black wires.
3.
Broken cord at the output of the charger. It usually breaks at the plug itself or at the base of the charger. Especially for those who like to talk while charging the phone.
Called the device. Insert the lead of a thin part into the center of the connector and measure the resistance of the wires.
4.
Transistor + resistors. If there is no visible damage, first of all you need to unsolder the transistor and ring it. It must be borne in mind that the transistor
MJE13005 the base is on the right, but it also happens the other way around. The transistor may be of a different type, in a different housing. Let's say MJE13001 looks like a Soviet KT209 with the base on the left.
Instead I installed MJE13003. You can install a transistor from any burnt-out lamp - a housekeeper. In them, as a rule, the filament of the bulb itself burns out, but the two high-voltage transistors remain intact.
5. Consequences of overvoltage. In the simplest case, they are expressed in a short-circuited diode D1 and a broken resistor R1. In more complex cases, the MJE13005 transistor burns out and inflates capacitor C1. All this simply changes to the same or similar details.
In the last two cases, in addition to replacing the burnt conductors, you will need to check the resistors around the transistor. With the diagram this will be easy to do.
Causes of mobile phone charger malfunctions
The most common cause of memory failure is negligence during operation.
Phone charger repair
Possible causes of breakdowns of the mobile phone charging unit
1. Broken wire at the plug and at the base of the charging unit. You can break the wires when charging is on during calls.
You need to pull the plug out of the phone socket not by the wire, but by the plug body.
2. Failure of elements of the electronic board of the charger. Very often the charger is left plugged in and not removed from the outlet. At the same time, all electronic board The charger is constantly under voltage, which reduces the service life of the board's radio elements.
Incorrect order of turning on and off the charger also leads to premature wear of the unit elements.
If you disconnect the phone from the charger under voltage, sudden voltage surges occur that exceed the maximum permissible operating voltages of the elements. This is due to transient processes that occur in the memory when the load is removed (the phone is turned off) under voltage. If the charger is used correctly, the phone is connected and disconnected with the charging switched off.
Do-it-yourself method for repairing a phone charger
You don’t need to be a big specialist to find and repair a broken wire from the charging unit to the plug. Damage to the wire can be determined when the phone is connected. Having connected the phone to charging, bend the wire at the plug u of the base of the unit, while simultaneously monitoring the continuity of the battery charging process.
These are the places where wire breaks most often occur. If a break is found at the very base of the plug, then cut the wire at a distance of 5-7 mm from the plug. This is necessary in order to be able to solder an entire part of the wire. The soldered wires are insulated separately with a thin heat-shrinkable tube.
When the places where the wires are soldered are insulated, a thicker heat-shrink tube is placed on the plug to make the soldering area rigid. Sometimes a wire break occurs at the very base of the plug, then the plug is completely freed from the plastic seal and the wires are soldered directly to the plug.
Do not reverse the polarity of the plug wires. The break point is also found with a multimeter in audio testing mode or visually. The found location of the wire break is cut off with a small margin on both sides. Clean the wire from the top insulation. Then it is cut, stripped of insulation, twisted and soldered, having previously placed a thin heat-shrink tube on each wire, and a thicker tube on the common wire.
After soldering, put thin tubes on the wires and deposit them, heating them with a soldering iron. At the end, a thicker tube is put in place of the deposited thin tubes so that the thick tube overlaps them in length. When soldering wires, observe the polarity according to their color. A new cable with a plug for your phone brand can be purchased at specialized stores. Then repairing the phone comes down to simply replacing the faulty wire.
Type of faulty capacitors
Another common malfunction of a phone charger is a failure of contact between the pins of the power plug. The spring contacts of the power plug often move away from the contact pads on the printed circuit board. To eliminate such a malfunction, it is enough to bend these contacts located inside the block.
Open the block cover. It is good if there are screws securing the charger cover, and if they are soldered. In this case, you need to use a hacksaw blade with fine teeth to cut a slot around the entire perimeter of the lid. Having eliminated the malfunction, close the lid and secure it with 1 cm wide tape.
More complex, but quite accessible to an electrician, are device breakdowns associated with repairing elements of the phone charger circuit board. First of all, they open the memory and take out the board. Repairs begin with a visual inspection of the elements printed circuit board and the condition of its tracks.
Scheme of a pulse charger for a phone
When inspecting the elements, pay attention to swelling of the upper part of the capacitors, darkening and damage to the integrity of the resistors. Darkening of the resistors and tracks underneath indicates an excess operating temperature. In this case, the resistor itself is checked for resistance and the diodes and transistors are checked.
The transistor pinout and memory circuit for your phone brand can be found on the Internet. If the malfunction cannot be visually detected, turn on the device and measure the input mains voltage. If the mains voltage is present and a faint sound of the pulse transformer is heard, then the output voltage of the unit is measured.
I wonder what the Siemens charger (power supply) consists of and whether it is possible to repair it yourself in the event of a breakdown.
First, the block needs to be disassembled. Judging by the seams on the body, this unit is not intended for disassembly, therefore it is a disposable item and you don’t have to place much hope in the event of a breakdown.
I literally had to tear apart the body of the charger; it consists of two tightly glued parts.
Inside is a primitive circuit board and several parts. The interesting thing is that the board is not soldered to the 220V plug, but is attached to it using a pair of contacts. In rare cases, these contacts may oxidize and lose contact, leaving you thinking the unit is broken. But I was pleasantly pleased with the thickness of the wires going to the connector for the mobile phone; you don’t often see a normal wire in disposable devices; usually it is so thin that it’s scary to even touch it).
There were several parts on the back of the board; the circuit turned out to be not so simple, but still not so complicated that you couldn’t fix it yourself.
Below in the photo are the contacts of the inside of the case.
There is no step-down transformer in the charger circuit; its role is played by an ordinary resistor. Next, as usual, a couple of rectifying diodes, a pair of capacitors for rectifying the current, then comes a choke and finally a zener diode with a capacitor completes the chain and outputs the reduced voltage to a wire with a connector to the mobile phone.
The connector has only two contacts.
Increasingly, people are having problems with the charger failing, which leads to unpleasant consequences, since it becomes impossible to charge the phone if there is no other alternative to the charger. In today's article we will look at all types of charger breakdowns and repairs.
And so, first, let’s determine the main reasons for the failure of the charger, it could be:
- Break in the power supply wire of the device;
- Damage to the charger unit;
- Broken contacts, connections or wires in the plug or power supply;
Most often, the cause of charger failure is a break in the internal wires or damage to the connections between the plug or block. In such cases, the device can be taken to service centers or repaired yourself. In this article we will look at the second option; as an example, we will use a charger with a thin plug from Nokia.
To repair the charger we will need:
- Regular multimeter;
- Knife for cutting wires;
- Soldering iron and solders;
- Electrical tape and heat shrink tube, if available;
- A roll of thin copper wire for connecting contacts or damaged parts;
The first thing we will do is look for damage in the wire or contact connections. It is quite easy to determine the place where the wire broke; this is facilitated by the non-standard color or smaller diameter of the wire itself.
If you were unable to visually determine the location of the break, then the damage may not be a break in the wire, but a defect in the connections between the device unit or the charging plug.
Let's start repairing the charger. First of all, we cut off the wire in the area of 7-10 cm from the plug; if a break is not detected, we can connect the plug back to the power supply. Therefore, it is not advisable to cut the wire close to the plug or power supply, since after that we will not be able to solder it back.
Next, we clean the wire from the insulation (the one on the power supply side). We take a multimeter and set the maximum permissible voltage to 20V. (You can find out more about how to use a multimeter in). We connect the contacts of the multimeter to the broken and cleaned wires and insert the charger into the network.
If the multimeter shows any value, it means there is no damage to the power supply and wire. In our case, the multimeter showed 7V - this means that the power supply is working properly, since the rated output voltage of the device is equal to the same value.
We do the same action with the charger plug. We clean the wire from the insulation and insert a thin wire into the inner part contact wire, this will be needed for precise measurement multimeter for the nominal value of the plug.
In the multimeter, select the continuity mode and touch one end of the probe to one of the protected wires, and the other, first to the plug, then to the inserted wire. If the multimeter emits sound signal, then this will mean that there is voltage between the plug and the wire and that the plug itself is working.
If the device does not emit a sound alert, it follows that the plug is faulty and there may be damage to its contacts. In such cases, you can go to the store and buy a new charger or replace only the plug, but you can also repair it, which is what we will do now.
If you have another working plug, you can replace it by simply soldering the new one to the old power supply, but it is important to observe the polarity; for this, each cord is color-coded; all wires must be soldered in the corresponding colors.
But sometimes it happens that the color marking is missing, in such cases you need to plug the charger into the network and connect the new plug to the phone. Next you need to connect all the plug wires to the wires charging block. If the phone will switch into charging mode, then you did everything right. If not, then change the wire connections until the phone goes into charging mode.
After this we proceed to soldering. If you have a heat-shrink tube, then before soldering, put it on one of the wires, then solder both ends, observing the polarity, then wrap the joint with electrical tape and put on the heat-shrink tube again.
But if you do not have an additional plug, then you will have to repair the old one. To do this, you will need to carefully remove the rubber coating from the old plug with a knife, while trying not to damage the connections of the plug itself.
After this, we check the functionality of the plug. We plug in the charging unit and connect the cord to the phone. If everything works, isolate all connections and attach heat-shrink tubing to the plug. After which the charger is ready for use.
But it happens that when cutting the wire and checking the voltage, it turns out that there is no voltage, then in this case you will also have to cut the wire opposite the charging unit, retreating about 7-10 cm. It is necessary to protect the wire coming out of the power supply from damage, after which you need to measure the presence of output voltage. If there is voltage, this indicates that the charging unit is working properly.
In our case, it turned out that one conductor of the plug was broken. This is difficult to detect visually. The best option may be to buy a new wire and solder it instead of the old one.
In this case, you also need to observe the polarity, and before soldering, check the wire contacts by connecting the charging unit to the network and the plug to the phone. If the phone begins to accumulate charge, then you can start soldering the wires, and then insulate them.
If the charger wire and plug are in good condition, then the damage is most likely in the charging unit. Perhaps the problem could be a broken contact inside the charger. To fix the damage, you need to disassemble the charger unit and check all wires and contacts for breaks. If everything is fine with them, then the problem lies in the charger unit itself. At the same time, without having electrical engineering skills, you will not be able to repair the charging unit. In this case, you will have to buy a new charger or take the old one to a service center.
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