Very often, equipment breakdowns are so basic and easily fixable that sometimes you don’t even want to take on repairs, it’s not of interest, but you have to. Recently, an acquaintance of mine turned to me for help, who had previously lived poorly, and recently, due to the crisis, also lost his job.
Shows universal type charger Frog for lithium batteries from phones, with broken fastenings of the pressing part, and asks if anything can be done. He says they sat on her. The first thought was to suggest throwing it away and buying a new one, but looking at his face, saddened by the breakdown, I changed my mind and decided to help.
There were two new crocodiles available in insulation, only the tip protruded, and it was decided to solder to the wires going to the antennae and connect to the battery with crocodiles. I plugged the charger into the socket to make sure that it worked at all, and my efforts would not be in vain, and began to disassemble it.
First, 2 screws were unscrewed, securing the antennae to the part that presses the battery; the antennae were intact. Often during work these antennae break off and it becomes impossible to use, so I kept the antennae as a reserve. If anyone doesn’t know how to use such a charger, let me explain: we use lithium ion battery, from cell phone, camera and other similar equipment. We combine the antennae of the charger with its plus and minus contacts, they are labeled on the battery, and press the battery against the charger body using the spring of the pressing part. The LED on the charger should light up, indicating that there is contact between the antennae and the battery contacts. For those who may need to send a similar charger, with a more serious breakdown, I will give one of the circuit diagram options:
Charger circuit
Let's return to our repair, unscrewing two screws and disassembling the frog body. It remained to determine which of these wires going to the antennae is positive and which is negative. Such a check is rather arbitrary, because such chargers have, or automatic detection polarity, and then there are no buttons, or there is a polarity reversal button.
But still, I wanted to assemble it so that the red probe was a plus and the black probe was a minus. Then I removed the board and found a common wire connected to one of the wires; it was connected to the polygon on the board. It was decided to count it as a minus. Then it was a matter of technology; we needed beautiful wires to connect with the wires coming from the antennae. I just had the same wiring from the computer speaker. The speaker itself and the connector were cut off; I decided to take the length of the wires sufficient for easy connection to the battery contacts.
Recently, I have acquired the habit of paying attention to the aesthetics of connections in a device, no matter whether I make it for myself or for people, for money or for purely symbolic gratitude. Therefore, I bought myself a supply of heat shrink, of different diameters, for all occasions, and decided to abandon the snot on connections in the form of electrical tape. Which, by the way, not only looks ugly, but also tends to slide off the wire connection over time and expose it. I don’t think I need to explain to anyone what this entails.
So here, too, before soldering the wires, I put two pieces of heat shrink on the wires, and after soldering, he heated them over a fire with lighters. The result is beautiful, reliable insulation. By the way, in the West, judging by the insulation of LEDs and buttons, computer cases, they have long abandoned the use of electrical tape and package everything that remains for long-term use only in heat shrink. Before soldering the wires, out of habit, I tied the wires in a knot, so that it would be impossible to pull out the wires by using force. A unit whose size is larger than the hole into which the wire is inserted in the charger body will not allow you to do this.
All that remains is to assemble the charger in the case and test it by plugging it into the network and connecting it with crocodile clips to the battery contacts. Everything worked as it should, the LED began to blink, indicating that the battery was charging. And as it turned out, I was not mistaken with the polarity and color of the crocodiles when soldering the wires. Happy repairs everyone! The author of the article is AKV.
Now, more than ever, the number of gadgets per person has reached its maximum.
Phones, tablets, laptops, various wireless headsets– all this abundance of equipment has a power source and, accordingly, a charger for it.
The phone is not charging from the charger - what should I do?
Chargers are often carried with them in a bag or pocket, and so that they take up minimal space, their cords are twisted with a bend and tension.
This in turn leads to an almost invisible wire break and charging inoperability. Just break in the cord- this is the most common breakdown in these types of devices, and, frankly, it’s a pity to throw it away because of this.
Yes, you can, of course, buy a new one and not have to worry, but if the device is non-standard, for example, an old model phone, then it is not always possible to find such a charger. And at a flea market they might give you a block with the same problem, and no one needs the extra expenses.
Therefore the repair charger- it’s a useful and worthwhile thing.
How to fix a charger for a phone, smartphone, tablet with your own hands
Below, this article will describe a simple repair method that does not require special equipment, which will give your charger a second life.
The photo shows a charger with a problem in the cord.
A cliff is not always visible to the naked eye. It can be hidden under the thickness of the main (top) insulation and remains almost invisible.
But, as practice shows, a fracture most often occurs near the entrance to the block or at the base of the plug.
To find the location of the break, just connect the switched-on charger to the phone and move the cord in a suspicious place.
As soon as you see that charging “started” for a moment, it means that there is a break in the place where you were moving at that moment.
In this case, upon closer inspection, the fracture and break were visible even without movement. It just happened to be at the entrance to the power supply.
The main problem in repairing such blocks is that they are not collapsible. Therefore, to get to the electronic board, you need to be careful and some effort.
Using a screwdriver and a knife, you need to pry up the base of the back cover and remove it.
You should pry where the cord enters the device. If the entrance is too tight, you can trim the rubber clamp slightly.
This must be done carefully so as not to cut the wire at all.
Using a screwdriver, we try to lift the lid up.
It may happen that it cracks in half, but more often, as in this case, the lid was removed entirely, without damage.
It was even clear that it had latches, and in the body of the charger there were recesses for them.
This means that after repair it is possible to put the cover in its place without using glue.
When the cover is removed, you need to pull the printed circuit board out of the case. Since it “sits” tightly, a screwdriver will help you get it out. By resting the blade of the screwdriver against the body and hooking its tip into one of the soldering points, we pull the board out.
The design of the case is such that when the board is inserted inside, its input contacts are connected to the clamps of the power plug pins. Therefore, when installing the board back into the case, you need to take this point into account.
The photo below shows the board with all its “internals”. The wires are soldered at the bottom.
View from the opposite side.
And here in the photo are the tracks for the input contacts.
The wire will have to be cut below the place where the damage is located. But it is very important to remember which wire is “+” and which is “-”. In some cases, the wires are color coded, with red being the positive wire and black being the negative wire.
When marking with color, you can safely cut it, and then simply solder the wires, observing the polarity.
In our case, the wires are the same color, but since the cord is flat, you can see which side of the cord the wire goes to negative and which to positive. Mark, and then cut.
Without losing the mark, strip and tin the wires on the cord.
We solder them to the board one at a time, observing the polarity.
There is usually a polarity marking on the printed circuit board at the soldering point.
To prevent the output cord from dangling, we wrap a bandage of black electrical tape around its input part. The thickness of the bandage should be such that it fits into the slot for the wire and is fixed in it.
Before installing the cover, check the operation of the device. We turn it on and connect it to the phone. If the phone is on at the moment If you don’t have it with you, we use a DC voltmeter.
Since the internal contact in the socket has a very thin tube, and the probe of the device does not go into it, you can use a piece of thin copper wire to check.
Having inserted it into the internal contact tube, we connect the probe of the measuring device to it and the outer terminal of the plug.
The voltmeter shows that voltage is present, which means that the fault has been fixed.
Now we snap the back cover.
We connect the phone and enjoy the results of the work done.
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. In this case, the entire electronic board of 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 transition processes that appear in the memory when the load is removed (the phone is turned off) under voltage. At correct operation The phone charger 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 observing 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. New wire with a plug for your phone brand can be purchased in 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 board. First of all, they open the memory and take out the board. Repairs begin with visual inspection 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 that the operating temperature has been exceeded. In this case, the resistor itself is checked for resistance and the diodes and transistors are tested.
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 measure output voltage block.
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 values 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. Necessary element, the blocking oscillator 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.
Greetings, radio amateurs!!! While going through old boards, I came across a couple of switching power supplies from mobile phones and I wanted to restore them and at the same time tell you about their most frequent breakdowns and elimination of shortcomings. The photo shows two universal schemes for such charges, which are most often found:
In my case, the board was similar to the first circuit, but without an LED at the output, which only serves as an indicator of the presence of voltage at the output of the block. First of all, you need to deal with the breakdown; in the photo below I outline which parts most often fail:
And we will check all the necessary parts using a conventional DT9208A multimeter. It has everything necessary for this. A mode for testing diodes and transistor junctions, as well as an ohmmeter and a capacitor capacitance meter up to 200 µF. This set of functions is more than enough.
When checking radio components, you need to know the base of all parts of transistors and diodes, especially:
Now we are completely ready for inspection and repair pulse block power supply. Let's start checking the unit to identify visible damage; in my case there were two burnt resistors with cracks on the body. I didn’t find any more obvious shortcomings; in other power supplies I came across swollen capacitors, which also need to be paid attention to first of all!!! Some parts can be checked without desoldering, but if in doubt, it is better to desolder and check separately from the circuit. Do soldering carefully so as not to damage the tracks. It is convenient to use a third hand during the soldering process:
After checking and replacing all faulty parts, do the first switching on through a light bulb, I made a special stand for this:
We turn on the charger through the light bulb; if everything works, we screw it into the case and rejoice at the work done, but if it doesn’t work, we look for other shortcomings; also, after soldering, do not forget to wash off the flux, for example, with alcohol. If all else fails and your nerves are on edge, throw away the board or unsolder it and take the live parts to stock. Good mood to everyone. I also suggest watching the video.
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