Very often, equipment breakdowns are so elementary and easily removable that sometimes you don't even want to take on repairs, it is not of interest, but you have to. Recently, a friend of mine turned to me for help, who had not lived well before, and recently, due to the crisis, has also lost his job.
Shows universal charger type Frog for lithium batteries from phones, with the fasteners of the pressing part broken off, and asks if anything can be done. Says that they sat on it. The first thought was to offer him to throw it away and buy a new one, but looking at his face upset by the breakdown, he changed his mind and decided to help.
There were two new crocodiles in isolation, 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 an outlet to make sure that it worked at all, and my efforts would not be in vain, and began to disassemble.
First, 2 screws were unscrewed, fastening the antennae to the part holding the battery, the antennae were intact. Often, during work, these antennae break off, and it becomes impossible to use, therefore, he left the antennae in reserve. If someone does not know how to use such a charger, I will explain: we take a 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 signed on the battery, and we press the battery to the charger body, due to 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 options for the circuit diagram:
Charger circuit
Let's go back to our repair, having unscrewed two screws, disassembled the frog's body. It remained to determine which of these wires leading to the antennae is plus and which is minus. Such a check is rather arbitrary, because on such chargers there is either automatic polarity detection, and then there are no buttons, or there is a polarity reversal button.
But all the same, I wanted to assemble so that the red probe was a plus, and the black one was a minus. Then I removed the board and found a common wire connected to one of the wires, it was connected to a polygon on the board. It was decided to count it as a minus. Further a matter of technology, beautiful wires were needed to connect with the wires coming from the antennae. I just had such wiring from a computer speaker. The speaker itself and the connector were cut off, I decided to take the length of the wires sufficient for convenient connection to the battery contacts.
Recently, I have gotten into the habit of following the aesthetics of connections in the device, no matter if I make it to myself or to people, for money or for purely symbolic gratitude. Therefore, I bought myself heat shrinks with a margin, of different diameters, for all occasions, and decided to abandon the snot on the joints in the form of electrical tape. Which, by the way, not only does it look ugly, but also strives over time to crawl off the wire connection and expose it. What this is fraught with, I think there is no need to explain to anyone.
So here, too, before soldering the wires, I put two pieces of heat shrink on the wires, and after soldering I warmed up the lighters on fire. The result is a 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 pack everything that remains for long-term use only in heat shrinkage. Before soldering the wires, out of habit, I tied the wires in a knot, so that it was impossible to forcefully pull the wires out. To do this, it will not allow just the node, the size of which is larger than the hole into which the wire is passed in the charger case.
It remains only to assemble the charger in the case and test it by plugging it in and connecting it with the crocodiles to the battery contacts. Everything worked as it should, the LED began to blink, indicating that the battery is charging. And as it turned out, with the polarity and color of the crocodiles, when soldering the wires, I was not mistaken. Happy repairs to everyone! The author of the article is AKV.
Causes of mobile phone charger malfunctions
The most common reason for the failure of a charger is a careless attitude towards it 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 jack not by the wire, but by the plug body.
2. Failure of the elements of the electronic board of the charger. Very often the charger is left plugged in and is not removed from the socket. In this case, the entire electronic board of the charger is constantly energized, which reduces the service life of the radio elements of the board.
The wrong order of switching on and off the charger also leads to premature wear of the unit elements.
If the phone is disconnected from the charger while energized, sudden voltage surges occur that exceed the maximum permissible operating voltage of the cells. This is due to transient processes that occur in the memory when the load is removed (disconnecting the phone) under voltage. If the charger is used correctly, the phone is connected and disconnected with the charger turned off.
DIY phone charger repair technique
You do not need to be a great specialist to find and fix a broken wire from the charging unit to the plug. Wire damage can be detected with the phone connected. Having connected the phone to the charger, bend the wire at the plug u of the base of the unit, while simultaneously observing the continuity of the battery charging process.
In these places, wire breaks most often occur. If a break is found at the very base of the plug, then the wire is cut at a distance of 5-7 mm from the plug. This is necessary in order to be able to solder the whole part of the wire. The soldered wires are insulated separately with a thin heat-shrinkable tube.
When the soldering points of the wires are insulated, a thicker heat shrink tube is put on the plug to stiffen the soldering point. 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 the audible dial mode or visually. The found place of wire breakage is cut with a small margin on both sides. Peel the top insulation off the wire. Then it is cut off, stripped of insulation, twisted and soldered, after putting on a thin heat-shrinkable tube on each wire, and a thicker tube on the common wire.
After soldering, they put thin tubes on the wires and upset them, heating them with a soldering iron. At the end, a thicker tube is put on in place of the upset thin tubes so that the thick tube overlaps them in length. When soldering wires, observe the polarity according to their color. You can purchase a new cord with a plug for your brand of phone from specialized stores. Then phone repair comes down to a simple replacement of the faulty wire.
Type of faulty capacitors
Another common malfunction of a phone charger is a loose contact between the pins of the power plug. The spring-loaded pins of the mains plug often extend from the contact pads on the PCB. To eliminate such a malfunction, it is enough to bend these contacts 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 cut a slot around the entire perimeter of the cover with a hacksaw blade with fine teeth. After fixing the malfunction, the lid is closed and fixed with tape 1 cm wide.
More complex, but quite affordable for an electrician are device breakdowns associated with the repair of elements of the phone charger board. First of all, they open the memory and take out the board. Repair begins with a visual inspection of the elements of the printed circuit board and the condition of its tracks.
Pulse charger circuit for phone
When examining the elements, attention is paid to the swelling of the upper part of the capacitors, darkening and violation of the integrity of the resistors. Darkening of the resistors and the tracks under it indicates that the operating temperature is exceeded. In this case, the resistor itself is checked for resistance and the diodes and transistors are ringed.
The pinout of the transistors and the memory circuit for your phone brand can be found on the Internet. If it was not possible to visually detect a malfunction, 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 case of a breakdown.
First, the block needs to be disassembled. Judging by the seams on the case, this unit is not intended for disassembly, therefore, the thing is disposable and there is no need to pin high hopes in the event of a breakdown.
I had to literally raskurochit the case of the charger, it consists of two tightly glued parts.
Inside is a primitive board and a few details. Interestingly, the board is not soldered to the 220V plug, but is attached to it with a pair of pins. In rare cases, these contacts can oxidize and lose contact, and you think that the block has broken. But the thickness of the wires going to the mobile phone connector pleased me pleasantly, you don't often find a normal wire in disposable devices, usually it's so thin that it's scary to even touch it).
There were several details on the back side of the board, the circuit was not so simple, but still it is not so complicated that you would not be able to 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; an ordinary resistor plays its role. Then, as usual, a couple of rectifying diodes, a pair of capacitors for rectifying the current, then a choke and finally a zener diode with a capacitor complete the chain and output the reduced voltage to a wire with a connector to a mobile phone.
The connector has only two pins.
Now, as never before, the number of gadgets per person has reached the maximum value.
Phones, tablets, laptops, various wireless headsets - all this abundance of technology has a power source and, accordingly, a charger for it.
My phone won't charge from the charger - what should I do?
Chargers are often carried with them in a bag or pocket, and so that they take up a minimum of space, their cords are twisted with a bend and a stretch.
This, in turn, leads to an almost imperceptible wire break and inoperability of charging. Just break in the cord - this is the most common breakdown in such types of devices, and, frankly, it is a pity to throw it away because of this.
Yes, you can certainly buy a new one and not suffer, but if the device is non-standard, for example, an old model phone, then it is not always possible to find such a charge. And at the "flea market" you can slip a block with the same problem, and no one needs extra spending.
Therefore, repairing a charger is useful and worthwhile.
How to fix a charger for a phone, smartphone, tablet with your own hands
Below, in this article, a simple repair method that does not require special equipment will be described, which will give your charge a second life.
In the photo - charging with a problem in the cord.
The cliff is not always visible with the naked eye. It can be hidden under the thickness of the main (top) insulation and remains almost invisible.
But, as practice shows, the fracture occurs most often near the entrance to the block or at the base of the plug.
To locate the break, just connect the included charger to the phone and wiggle the cord in a suspicious place.
As soon as you see that the charging "went" for a moment, then there is a break in the place where you were moving at that moment.
In this case, looking closely, the break and cliff were visible even without movement. It just turned out at the entrance to the power supply.
The main problem in the repair of such blocks is that it is not collapsible. Therefore, to get to the electronic board, you need to be careful and some effort.
Using a screwdriver and a knife, pry off the base of the rear cover and remove it.
Pry should be at the point where the cord enters the device. If the entry is too tight, you can cut the rubber strap slightly.
This must be done carefully so as not to cut the wire at all.
Having poked it up with a screwdriver, we try to lift the cover up.
It may happen that it cracks in half, but more often, as in this case, the cover was removed entirely, without damage.
It was even seen that it had latches, and in the charger case there were recesses for them.
This means that it is possible, after repair, 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 to get it out. Leaning the blade of the screwdriver against the body and hooking it with the end of one of the soldering points, we pull the board out.
The structure of the case is such that when the board is inserted inside, its input contacts are connected to the terminals of the pins of the power plug. 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 "guts". 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 where the damage is. But it is very important to remember which wire is "+" and which is "-". In some cases, the wires are color coded, red is positive and black is negative.
With color marking, you can safely cut, and then just solder the wires, observing the polarity.
In our case, the wires are one-color, but since the cord is flat, you can trace from which side of the cord the wire goes to minus, and from which to plus. Mark, and then crop.
Without losing the label, strip and tin the wires on the cord.
Solder them one by one to the board, observing the polarity.
The PCB usually has polarity markings at the soldering point.
To prevent the cord from dangling at the outlet, we wind a bandage of black electrical tape around its entrance part. The thickness of the band should be such that it fits into the slot for the wire and locks into it.
Before installing the cover, we check the operation of the device. We turn it on and connect it to the phone. If the phone is not with you at the moment, 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 tube of the internal contact, we connect the probes of the measuring device to it and the external output of the plug.
The voltmeter shows that voltage is present, which means that the breakdown has been repaired.
Now we snap the back cover.
We connect the phone and enjoy the results of the work done.
Greetings radio amateurs !!! Looking through old boards I came across a couple of switching power supplies from mobile phones and 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 of 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 acts as an indicator of the presence of voltage at the output of the block. First of all, you need to deal with the breakdown, below in the photo I outline the details which most often fail:
And we will check all the necessary details using a regular DT9208A multimeter, which has everything you need for this. Continuity mode for diodes and transistor junctions, as well as an ohmmeter and capacitor capacitance meter up to 200μF. 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 to check and repair the switching power supply. Let's start checking the block to identify visible damage, in my case there were two burnt resistors with cracks on the case. I did not reveal any more obvious shortcomings, in other power supplies I met swollen capacitors, which also need to be paid attention to in the first place !!! Some details can be checked without soldering, but if in doubt, it is better to unsolder and check separately from the circuit. Do the 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 defective parts, do the first turn on through a light bulb, I made a special stand for this:
We turn on the charger through the light bulb, if everything works, then we twist it into the case and rejoice at the work done, if we are not looking for other disadvantages, also after soldering, do not forget to wash off the flux, for example, with alcohol. If all else fails and nerves are in the balance, discard the board or solder and select live parts in stock. Everyone is in a good mood. I also suggest watching the video.
