Very often come across the repair of "non-charging" phones Nokia.. I want to immediately note that with increasing model Row And the improvement of charging schemes, their reliability decreased by an order. Who in his practice did not come across a problem how to understand the phone is charged or not?
Of course, this can be checked by voltage growth on the battery itself, but this method is quite slow and it is not always possible to get to the battery contacts. You can look at the running charging icon on the phone, and wait for the long-awaited message. "Charging Completed" Or constantly remove the battery and whether the cherished milqualities in it appeared ...

Personally, I basically make charging control, by current consumed from charger. For this I have cords from burnt « chinese charging» , I am sure that every wizard has plenty of them that I connect to laboratory block Nutrition with adjusting voltage and current. For phones Nokia.i exhibit the charging voltage 5,7V. and charging current from 600 Ma before 1100 Ma. Do not forget that in the modern phones of this brand, the charging current restriction controls the phone, but in previous models This task was performed by the phone and the charger itself. I think that you have come across such a problem before, when the phone completely refused to charge from "Chinese charger" Devices and with the original everything was fine.

After all, it is no secret that the stable tension and the correct current of charging of each particular battery, it is a bare time and trouble-free work phone But unfortunately, not all understand this, especially the "Mount of the Master" who completely throw out the entire goal of charging and control the current, and they put a jumper with a diode directly from the charger on the battery terminals. Remember, soDO It is impossible!

I would like to make it easy to facilitate the process of finding and eliminating a malfunction, building a small algorithm of work:

1. If you receive an uncharged phone to you, check the integrity of the contacts of the charger and system connectors, depending on where the charger is connected.
2. Make sure the serviceability rechargeable battery, about high-quality contact terminals and their not contamination.
3. Check out charging voltage, applied to phones Nokia.it is about 5.7 volts.
4. Check the integrity of soldering system and charging connectors, very often new connectors "Fall off" In places of their soldering, cracks appear, firstly from application lead-free solderingSecondly from the unfinished attachment and thirdly from a negligent relationship to the phone itself, it is usually a rough connection and disabling the charger connector.
5. Now go to K. messages that give out the phone When the charger is connected:
   • "Not charging" - As a rule, a problem with the temperature sensor, the charging controller cannot determine the battery temperature and does not allow its overheating. As a rule, it is a thermistor resistance to 47 com and is located nearby with a battery.
   • "The charger is not supported" - The problem is related to the deviation of the voltage of the voltage coming from the charger, and can be caused by the "sediment" of the voltage on the passive elements - capacitors, protective stabilids and varistors.
6. But it happens that everything is checked and the phone does not respond at all to the connection of the charger, the simplest reason for this can be a blown fuse in charge chain, but do not forget that he could overcome not only external source Power A and from Internal Fault Charging Controller or Battery itself.
7. There are cases when everything seems to be fine, the indication is the phone does not give out non-standard messages, but something is wrong, the voltage growth on the battery does not occur and consumption from the Tokan source occurs. This may be associated with a faulty current sensor which in most phones is installed on the board and on some models is made in the form of printed conductors in the inner layers of the board. Constructive - resistor with small transition resistance in tens millia Connected to negative (minus) output of the battery and installed in the maximum proximity to the battery connector.
8. Very often the problem lies in a faulty charging controller, Check it is possible, only replacing the obviously good one.
9. There are still cases of program errors when after all sorts of erasing and overwriting in the phone's memory is erased PM.in which stress calibrations are stored. You can check this too detailed information about the connected phone with the help of old good UFS.or any other type programmer MX-KEY, JAF, BEST, FENIX etc.

Of course it is not full listWhat can face when searching for a malfunction, but following this algorithm you will save a mass of time during repair. If you have your own gains in the search and troubleshooting charging in phones Nokia.i will gladly add an article and publish your methods and techniques for this

1. Lyrical retreat

Probably, there are not so many people in the world who are not known to the Finnish company Nokia. One of the main activities of which is the development, production and implementation cell phones.

Like any other company with a famous name, it is a "lackless piece" for various kinds of small (mainly Chinese) manufacturers who want to sell their products under someone else's brand. Due to which in the news, it often flashes reports about realization attempts (sometimes more than successful) fake electronic equipment. Such activities are illegal and negatively affects both the image of the original manufacturer and its financial condition.

However, in the overwhelming majority of cases, first consumers suffer from behind this, to which your humble servant belongs to. Because In the history of such falsifications, there are practically no cases when the quality of fake products was not inferior to the original. In this case, the result of the use of fake products can be not only moral or financial damage, but also harm to health.

It is no secret that most often manufacturers of "fakes" pay their attention to branded consumables and accessories. Because On the one hand, the production of such goods does not require large technical and production resources, and on the other, it allows you to get a tangible profit. As at the expense of lower costs compared with the original goods (which is negatively affected by the quality), and at the expense of the "brand", because Even with comparable capacity, the goods of famous companies are more expensive. On the device market mobile communications First place in the number of fakes, perhaps, occupy rechargeable batteries. For a long time to talk about the negative consequences of such a state of things, I think it is not worth it. The inflated battery can lead to anything, from fire to serious injuries. However, today it will be not talking about them, but about the adjacent group of goods - charging devices.

When you buy a mobile phone, in 99.9% of cases it is already equipped with a network charger. And everything would be wonderful if they had no need to use :). And since they need to use, then there is a possibility that it will fail. It can be lost, homemade favorite can blame cable, etc.

In addition, it is convenient when charger has several. One can use at home, another at work, the third is thrown into the cottage. This will charge the phone, no matter where you are. I think everyone from own experience It is known that the phone has a property to discharge at the most inopportune moment :).

I usually use two chargers, one at home and second at work. One charger is attached to the phone, and the second can be bought. There are two options here - buy an original charger and not original (not fake, but simply produced and sold under the brand name), compatible with your phone model. The original charger guarantees you full compatibility with a mobile phone and quality, but it is not always possible to be found on sale. And besides, it can cost significantly more than the original (although not always). If on sale there is both the original and not the original charger, then the buyer's choice. You can save some money, and you can support the financial "favorite" manufacturer :). I am with rare exceptions (it does not apply to mobile phones) Select the original charger.

2. Facts

Currently I use the Nokia E50 mobile phone. Almost immediately after buying a phone, I took care of the purchase of a second charger. Complete with the phone, the AC-4E model charger was attached. Using the services of one of the numerous online stores that implement mobile phones and accessories, I ordered a similar charger, pre-clarifying on the phone that the charging devices are original and sold in the appropriate package. When buying, I externally examined the device, the box corresponded to the image on the Nokia website, and the charger itself exactly was suitable for accuracy. I left him at work and used from time to recharging the phone. The charging process took place slower, but because The difference was insignificant (~ 75 minutes against 50), then I did not focus on this. Onemost moment (through ~ 3.5 months) This charger burned (with appropriate noise and smoke effects). There was a sharp click, and smelled with a burning plastic.

Because warranty card I could not find yes and time for implementation warranty obligations Then there was no, I decided to buy a new charger, and this from curiosity opened. By the way, to disassemble the Nokia charger - the task is not simple, although, unlike the overwhelming majority of chargers of other manufacturers, it provides for the possibility of disassembly. It's all about using the screws with the original head. Neither an ordinary screwdriver nor the cross-person nor an asterisk or a hexagon will help you.

For sale, such screwdrivers have not yet come across, perhaps in a specialized store selling spare parts for mobile phones, they are. As a result, putting serious physical efforts, I unscrew the screws with a flat screwdriver of a suitable size, but the screws of the screws were very damaged. So talking about the possibility of painlessly disassemble the charger does not have to. That, in general, well, because On the one hand, it allows you to perform operational repair of the device, and on the other hand prevents the end user to disassemble it to avoid injury. I imagined the spectacle unpleasantly struck: the charger's printed fee was partially covered with soot from the burnt resistor, one of the tracks on the printed circuit board burned. And most of all struck the low quality schemechnical solution, it resembled the cheapest Chinese chargers, the so-called "Know Name".

Because Time was pressed, I looked at the list of accessories on the Nokia website and chose new model Charger, AC-5E compatible with my phone. It attracted me exceptional compactness, which is important if the charger needs to take with you on a business trip or vacation. Then I turned to the nearest communication salon to me the company Euroset and acquired the above charger there.

It was sold in the original packaging with the Nokia logo and externally corresponded to the image on the company's website. The "Rostt" certification logo was also present on the housing. In the evening I returned home from work and set the phone to charge, after 20 minutes the story repeated. Running a click, smelled with a burning plastic. Charger failed. I have already started doubting, is everything in order with a mobile phone, perhaps, is he the reason for these fireworks? But I did not pay attention to it. In the end, all devices are divided into two categories - those that have already failed, and those with which it is about to happen :). The next day I returned to the salon and replaced the failed charger for a new one. After that, put the phone for charging with the old (complete) charger. Charging went as usual, I did not notice any anomalies. A few days later I set the phone to charge, using the new AC-5E charger. The phone battery was almost completely discharged, usually the charging process in this case takes about 50 minutes. An hour later I checked the phone, the charging process was still continued. The charger itself is noticeably heard, which I did not observe in the case of using a complete AC-4E.

Because I was not going to go anywhere, I decided not to turn off the phone and wait until it was fully charged. When the charging process ends, the phone publishes a short beep, and the battery indicator stops at the top point. This beep rang out 3.5 hours after I connected the phone to the charger.

Curiosity won, and I disassembled a new charger. The scheme implementing solution used in it also reminded me of the AC-4E charger and its alleged cheap Chinese counterparts in the non-existence. Then I could no longer tolerate and disassembled the Charger of the AC-4E, which my phone was equipped. I must say that I saw me on one side pleased - the quality of this device was very good, and on the other - it was upset, because This meant that all chargers acquired by me are most likely fakes.

Let's look at the chargers closer.

Note: Currently battery charging function mobile phone It is assigned to the phone itself and partially on the battery. In connection with which the charger is a conventional power supply with the input / output characteristics necessary in each particular case.

3. Original Nokia AC-4E Charger

Marking

Power connector

At the bottom of the case, you can see the name of the model, characteristics, barcode and serial number Devices. All inscriptions are printed clearly, plastic has a pleasant rough to the touch surface. On the inner surfaces of both parts of the housing, you can see the Nokia logo.

Printed circuit board

Printed circuit board

The one-sided circuit board is neatly, all parts are present, the voltage regulator is used (a small chip on the underside of the board). Apply both ordinary and SMD components. There is a "FRIWO" marking on the board, this is the name of the company that produced data charging devices by order of Nokia.

Judging by the information on the site, it is a fairly large company specializing in the production of power supplies and chargers. In order to compare the two "versions" of my AC-4E charger, I photographed the charger body from the outside and inside, the marking present on the housing, the printed circuit board and the power connector. I will do the same for the remaining two devices.

4. Nokia AC-4E Charger

Nokia AC-4E Charger, general form

Marking

The inner surface of the top

The inner surface of the lower part

Power connector

As you can see, it is impossible to distinguish this charger from the previous one. The same coating, exactly the same connector, the same marking on the bottom of the case, barcode and number. The same screws with the original head. In general, it is not for what. A somewhat different impression is formed if you look inside. The lower part of the housing is almost similar to the original charger. The upper part does not contain the Nokia logo on the inside.

Printed circuit board

Printed circuit board

The printed circuit board is generally accurate, but the circuitry solution is more primitive. SMD elements are not used, the manufacturer label is missing. In fact, it is one of the simplest options for the pulse power supply.

5. Nokia AC-5E Charger

Nokia AC-5E Charger, General View

Marking

Top cover

Power connector

Neat I. compact housing, exactly the same power cable as the original AC-4E, with the velcro clamp for fixing the cable in the folded form. All inscriptions are clearly applied - the model name, the Nokia logo, characteristics and barcode with the number. Inside, we see the fee, a very reminisant "budget" version of the AC-4E adapter. The same lack of manufacturer labeling, the same primitive circuitry solution (however, in this case, there are differences, which will be talked below).

As for the lack of labeling of the manufacturer, it is extremely strange, because On the case of the device you can see a small inscription ASTEC. This is the name of a large company producing diet blocks by order of many manufacturers of mobile phones. ASTEC is included in the Emerson Group of Companies.

6. Chargers of other manufacturers

In order to be able to compare ASTEC products with the available Nokia AC-5E charger, I disassembled two more of my original charging devices, one of them was supplied with telephone Siemens. C65, and the second is complete with the Motorola V3 RAZR telephone.

Charging circuit board siemens devices, view from above

Siemens charger printed circuit board, bottom view

Characteristics of the Siemens charger - 5 V, 350 mA.

Motorola charger printed circuit board, top view

Motorola charger printed circuit board, bottom view

Characteristics of the charger Motorola - 5 V, 550 mA.

Both of these devices are manufactured by ASTEC, which says marking both on the chargers themselves and on the device printed boards. As you can see, the boards are made very carefully, SMD elements are used. There is a manufacturer marking.

7. Field Tests

Let's return to the Nokia AC-5E charger. The only reason why charging the phone with its use could last so long - the inconsistency of the claimed characteristics, namely the small current. The case of the device is indicated that it provides a current of 800 mA at a voltage of 5 V. We will check with a multimeter, which current consumes the phone during the charging process when using the original AC-4E charger and this AC-5E.

To begin with, measuring the voltage in the network, as you can see, it corresponds to the standards - 225 V.

We measure the voltage in the network

For reference: On the ASTEC website, you can view the specifications of the charging devices of a similar group, they provide compliance with the specified characteristics at the network voltage in the range from 85 to 265 volts.

We measure the current consumed when using the original Nokia AC-4E charger. As you can see, the current consumed is 910 mA.

Characteristics declared for this device - 890 mA. The charger works stably and does not heat, which means some current in the current still exists.

And now I measure the current consumed when using the "budget" version of the Nokia AC-5E charger. As you can see, the current consumed is 330 mA.

Testing a fake charger AC-5E

In this case, the device is strongly heated during operation. So it works at the maximum of its capabilities. What is not surprising, taking into account the primitive circuitry and the denominations of the parts used. From here and the increased time full charge phone

8. Original Chargers Nokia AC-4E / AC-5E

In order to place all the points over "I", I decided to order two more Nokia charger, AC-4E and AC-5E models in the online store of Ultra Electronics. Let's start with the Nokia AC-5E charger, because I have not seen its original version.

Because It is not possible to distinguish the original from the fake on external features, then I immediately deal with the charger.

Nokia AC-5E printed circuit board (orig.), Top view

Printing fee of Nokia AC-5E (orig.), Bottom view

As you can see, the filling of this charger in quality is very different from the "fake" for the better. The elements of the scheme occupy almost all free space inside the charger case. The circuitry solution is enough "complex", SMD elements are used. On the board there is a marking of the manufacturer "ASTEC". You can confidently say that this is an original product.

Original Nokia AC-5E Charger, General View

Nokia AC-5E power connector (Orig.)

Marking Nokia AC-5E (Orig.)

The appearance of the original charger, marking and power connector - all exactly copied in its fake version.

Let us turn to the remaining Nokia AC-4E charger.

Nokia AC-4E printed circuit board (Orig.), Top view

Nokia AC-4E printed circuit board (orig.), Bottom view

The charging device is on the "FRIWO" manufacturer labeling. The circuitry solution differs from the original charger discussed earlier, it was simplified. This is an ordinary tendency for almost all electronics manufacturers.

Nokia AC-4E Charger, General View

Marking

The inner surface of the lower part

Power connector

The appearance of the charger has not changed.

Despite the fact that this Nokia AC-4E charger is undoubtedly original, the quality of the instance that has fallen to me is unpleasant. However, let's talk about this in the second part of the "field tests".

Exterior of the original packaging of Nokia AC-4E and AC-5E charger packaging

9. Field Tests, Part Two

We will test the two remaining chargers, the "updated" version of Nokia AC-4E and Nokia AC-5E.

On the AC-5E case, it is indicated that the charger provides a current of 800 mA at a voltage of 5 V. We measure the current consumed.

Testing the original charger AC-5E

As you can see, it is 880 mA. In the process of operation, the device is slightly heated. In this case, the real characteristics of the device are even better than the stated. This charger can be recommended as a more compact replacement of the AC-4E model.

Unfortunately, with the testing of the "updated" version of the AC-4E charger is not so smooth. Let's start with the fact that when connected to the phone, the charger began to publish a low-frequency hum, and the phone itself did not even think to charge. I disassembled him and decided to check the output voltage directly on the contacts pCB. It turned out to be 5.8 in, which is quite normal for work without load. At this point, I drew attention to the charger cable, it consists of two lived in the isolation of black and white color, respectively. However, the wire of the black color, contrary to my expectations, was soldered to the contact "+" of the printed circuit board (what could be judged by the indications of the multimeter). So it turned out, the wires were soldes incorrectly.

In this case, we are dealing with a defective product. Apparently, the quality of the output control of products from the company "FRIWO" has worsened.

After I soldered the wires properly, the phone began to respond to the connections of the charger, and it was possible to measure the current consumed during the charging process.

Testing the original charger AC-4E

The result is 400 mA at the stated 890. Interpret such a result, in general, it is meaningless, because The device is obviously defective and subject to replacement.

10. Conclusions

Conclusions disappointing. Even when buying an "original" charger in the cabin of a well-known company you are not insured against fake. Moreover, appearance The devices are copied as well as, even knowing this problem, it is almost impossible to distinguish it from the original. Is that coming to the store along with a multimeter.

And a bit of positive: as the practical experience has shown, the phone itself, both in the case of the use of a fake charger, and in the case of using a defective copy of the original charger with incorrect polarity, remained alive. The inconvenience is delivered: the increased charging time, frequent cases of the output of fake chargers of the order and the fact that the fake had to be paid as the original charger.

With an increase in the fleet of mobile phones, the number of chargers that are included with telephones are growing proportionally. Given the poor quality of our power grids, these devices often fail. This is especially true of models of unknown manufacturers purchased on radio rolls due to their low cost.

As a rule, to preserve profitability, such manufacturers use cheaper components in their devices, which inevitably entails a decrease in their reliability.

After, without worrying and the week, a similar charger for the Nokia phone bought on the radio storage failed on the radio machine, it was decided to find out the cause of the fault that had arisen and make the necessary changes in the scheme to increase the reliability of the device as a whole.

It should be noted that, comparing two chargers - a certified and "gray", the difference is not so easy and easy (photo 1). The device of the device of an unknown manufacturer (see photo 1, from above) is characterized by a less deep embossed of the Nokia logo inscriptions and technical characteristics Devices and lack of a silk-shaped icon regulating the method of disposal of the device at the end of its service life. In photo 2 and 3, the device is disassembled respectively and its mounting board.

The schematic diagram of the device was restored on the circuit board and as it can be seen is a classic pulse converter Return (Fig. 1). Similar simple schemes widely used in pulse blocks Power and chargers with a capacity of up to 25 W with appropriate use of more powerful parts.

The declared characteristics of the device - the output voltage of 5.7 V, current 800 mA.

And now briefly consider the description of the work of the scheme

The network voltage is fed through a current-limiting resistor R1 to the input of the rectifier, made on diodes D1-D4. On the transistor Q1, the autogenerator is assembled, the frequency of which is mainly determined by the characteristics of the applicable pulse transformer TF1. Resistor R3 sets the mode of operation of the transistor Q1. Stabilization of the output voltage occurs due to the use of the winding feedback Pulse transformer TF1 and chains D7, C4, ZD1. The Q2 transistor and the R2 resistor serve to limit the current of the transistor Q1 at the time of starting the autogenerator, as well as in the case of overload or short circuit At the output of the device. The circuit contains the simplest rectifier of the output voltage on diode D8 and C5 condenser. The R6 resistor serves to discharge the C5 condenser after turning off the device.

As a result of the inspection, a faulty transistor Q1 was found with marking 1003 and a burnt resistor R3. The burnt coating of the resistor did not allow to determine its resistance. In order to increase the reliability of the scheme as a transistor Q1, more powerful and widespread was used domestic transistor CT 940A (photo 4). The resistance R3 indicated in the scheme was selected in relation to a specific transistor to ensure the stable operation of the autogenerator and obtaining the necessary output current. It should be noted that due to the large variation of the characteristics of CT 940A transistors, in some cases, it may be necessary to change the resistance value of R3 specified in the diagram.

It should be noted that on the board in the space provided for this place there is no oxide capacitor, which must be connected at the output of the diode rectifier D1-D4. In this case, the auto-generator of the device actually operates in modulation mode with a straightened network voltage. For this reason, in many cases, such devices may not provide the declared output current required to charge the mobile phone battery consequence this may be, for example, an increase in total charging time. In some cases, the insufficient output current can lead to wrong work Battery charging schemes in a mobile phone, which ultimately can lead to a decrease in the battery life. If necessary, this missing condenser can be sought - its container can be no more than 10 μF per work voltage At least 450 V. I advise you to immediately with the installation of the capacitor, you solder in parallel with its mounting from the mounting resistor with a resistance of about 300 com for the discharge of this capacitor after disconnecting the device from the network. In addition, it is desirable to replace the R1 resistor to the resistor with a greater dissipation power, as it limits the charging current of this capacitor at the time of the device is turned on to the network. The board provides a place for the LED designed to indicate the operation of the device, and if necessary, it can be installed on a plate through a current-limiting resistor with a resistance of 680 ohms.

After repair, this charger works reliably for more than a year without comments. Given that the converter scheme used is widely used in many chargers, the described method of repair and improve reliability can be recommended for other similar devices.

• Micah / 04/19/2017 - 16:31

Maybe someone comes in handy schemes of the Charger Avalanche ATCH-S Nokia 6101, 5230 and others with a thin plug. The diagram drew himself from the printed circuit board. Here is the link

alexander / 20.12.2014 - 11:40

is it possible to pick up USB instead of the plug?

Zhenya / 27.11.2014 - 20:24

Explain the novice - what does 1 ohm resistor mean? Moreover, at a voltage of 220 V? If you throw a jumper there, the difference will be at all?

Andes / 12.07.2014 - 14:02

About the interference to the network and the big risk of fire agrees. In order not to repair the charging devices, the branded manufacturer makes them in an uncalate design. Further read for especially gifted. :) We look at the body of any charger. It says: Output: DC57V. There are a lot of old chargers including Nokia, Samsung, including Nokia, Samsung. Cut from such a good wire and solder + and _ wire with a connector from the burnt one. Isolate. Repair completed. People, why do you need the rest of the "hemorrhoids". Please do not be offended, but even if there is no one good, on the "for the bottle" on the radio machine :) You can dial a bunch, and do what is written above. Take care of people around you. Good luck!

Sergey / 05.22.2014 - 02:58

Chukchi is not a reader - Chukchi writer. Please note this, when that is a popular promotion. Now the problems are not with the repair of charging, but with merciless-giving ether with the interference of the simplest charging. And other crafts of playful handles of all stripes.

alex / 08.12.2012 - 12:28

artem / 21.02.2009 17:21 In general, after reading the posts here a little here and realized that the majority should not be understood in the schemes, and go to school syntax and spelling))))) Does people really be so difficult to erase! So here. Words not "the majority" and "most" not "learning" and "learn", since the word answers the question to what to do. "Will weighing!" You need to write so "write competently" to clarify here - and it's hard for you to write correctly ?? Teacher.

vGZIK / 12/07/2012 - 03:07

when combining the transistor, together with diodes and resisters, in most cases, trance is closed, so you still do it, if you can't buy a good one. I just liked the experience of 40 years old - I didn't drop it for a long time, I didn't turn around it, I didn't turn around 40 years old.

Mikhail / 03.11.2012 - 15:04

Hello read the article, but I have little questions for which you could give an answer. If it is not difficult for you - give me a little time. I will start with a small pre-history. On the this moment I can't find this situation that I can't go shop, in service center also. I can get radioetal only from those devices that have already been worked out (and there are many of them and every day arrived). I have only a mobile phone, the memory (very weak and does not care about the charging of my phone), a soldering iron, a device such as checklist (battery, diode and two wires). And many broken chargers and some broken phones. So the essence of the question: I would like to repair at least some of these chargers and increase the power of at least some. Various breakdowns - the nutrition on the phone goes, and does not charge (most common), it simply does not charge, the coil burned down, the coil burned, they closed something and so on. If you don't make it difficult to write me in more detail how it can be repaired in my conditions such things, maybe something else needs to get (I will immediately say not to lack the multimeter). The biggest problem is low-power chargers. I have very little knowledge but they are quite scarce. If not difficult, describe how and that. Regards, Mikhail

Sergey Dykyvich / 02.10.2012 - 11:48

Hello. I, author of this article on repairing a charger. After 4 years, I am surprised to discuss this topic with surprise. With different power supplies (and not only) I have for more than 25 years. Based on his many years of experience, I can say that, of course, CT940A (only with the letter a) here is not the most successful choice and this transistor works at the limit of its voltage capabilities. But. but. Then the task was to repair this cheap Chinese Go @ but quickly and literally for a penny (and another one was to buy on the market. There was no desire - then it was better to take a normal branded charging in the store two times more expensive). CT940A I had a lot of rolling and attaching his parameters I decided to "risk". Thus, the repair of this block cost me actually for free. This was the calculation. If you do more reliably, it is certainly better to put higher-voltage transistors - they have already mentioned (13003, 13005 and similar). And increase the reliability of the scheme with the CT940A, if you additionally add parallel primary winding RC transformer chain to reduce voltage emissions. RC Chain - the value is calculated, depending on the frequency of the conversion and some other parameters. Now it's not a lot of time, and desire, but, on the dressing, it can be something like - with 2200pf (by 300V), and R 100 ohms. It is advisable to see the voltage of emission oscilloscope with a dividing head 1: 100. Another option - instead of RC chains, you can put a chain of the connected successively high-voltage diode (reverse voltage of at least 400volt, for example, SF4007) and the suppressor 1.5K (special restrictive diode To suppress emissions with an operating voltage somewhere on 100 or 120 volts). Both diodes are included with the cathodes, and then the anode of the suppressor of the + power supply 300V, and the anode of the second diode to the CT940A collector. Good luck to everyone in repairs.

Sergey / 04/18/2012 - 14:45

Alex / 03/27/2012 - 10:36

Tell me how from charging Mobile., Which gives 5 in the post. Make the power output 3.7V post. Well, that you need to go there at the output to the diode, condenser or resistor, if yes, tell me the details parameters, the principle of connecting ??

enerjik / 03/20/2012 - 23:09

thank you for the article. Very helped.

Sanya / 03/10/2012 - 19:44

Yes, I agree, so this CT 940A instead of 13001 of the results of the result, the charger earned, but the joy was short, loading the device with an ammeter KT940 IMG burned out, it's good that through the lamp included the CZ happened. I think that if I deliver 13003 this will not happen, but I will not have a question. Do you put another resistor when you put a more powerful transistor?

serg81 / 13.02.2012 - 15:01

Excellent article! Thank you so much.

Olim / 07.02.2012 - 02:35

repair Nokia Charge

Maxim 444734111 / 01/21/2012 - 23:09

I don't know how with the reliability of KT940, but when I immediately charged, put 13003 in them from Energy Saving. Of the five fixed charges, two reinforced with sound-light effects when connected to 220. Usually fly in china charging: 13001, 1N4007, 2.2 ohm stenus in the chain 220, the stenus of 30 ohms in the base chain, and Stabitron by 6.2-6 , 8-7.5-10 volts. In the secondary chains, almost always everything.

Bobi61 / 11/10/2011 - 07:58

1. Tell me how to make an ACP-12E charger output voltage 5 volts, instead of 5.7 volts? 2. You can choose the watches 5B such a charger. 400ma?

pE [/ 28.06.2011 - 12:30

deputy District Transistor and Samemi-Thyristorn (Phase) Regulator!

Alexey / 08.11.2010 - 20:32

Is it possible somehow to force such a charge for a long time to give 5V with a current of 250mA? I tried to load the 22 ohm resistor unit and the voltage fell to 2.8V, I tried to put a complete bridge at the outlet of the stem diodes (SK14), the voltage rises almost one and a half times. LM7805 implanted on the yield, but at current 200mA, the stabilizer and the transistor begins to warm much, and at the entrance from the bridge, the voltage is set as far as 6V. I tried to put the Stabilitron on 15V (with one diode after the trance), the voltage rises to 11V, but at a load current of 250m After all, it is stated that it should be easy to keep such a load? :(

albert / 01.11.2010 - 11:06

Power Supply

Repair and refinement of cell charger phones Nokia.

With an increase in the fleet of mobile phones, the number of chargers that are included with telephones are growing proportionally. Given the poor quality of our power grids, these devices often fail. This is especially true of the models of the chargers of unknown manufacturers purchased on the radio rolls due to their low cost.

As a rule, to preserve profitability, such manufacturers use cheaper components in their devices, which inevitably entails a decrease in their reliability.

After, without worrying and the week, the similar charger for the Nokia phone bought on the radio launcher, it was decided to find out the cause of the fault that had arisen and make the necessary changes to the scheme to increase the reliability of the device as a whole.

It should be noted that, comparing two chargers - a certified and "gray" difference is not easy to find (Fig. 1). The body of the device of an unknown manufacturer (from above in Fig. 1) is characterized by a less deep embossed of the Nokia logo inscriptions and the technical characteristics of the device, as well as the absence of the silk screen of the icon regulating the method of disposal of the device at the end of its operation. In fig. 2 shows the device mounting board.

The schematic diagram of the device was restored by the circuit board. It is a classic reverse switching converter (Fig. 3).

Similar simple schemes are widely used in pulsed power supplies and chargers (up to 25 W).

The declared characteristics of the device - the output voltage of 5.7 V and load current 800 mA.

And now briefly consider the principle of operation of the power supply on concept (Fig. 3).

The network voltage is fed through a current-limiting resistor R1 to the input of the rectifier on D1-D4 diodes. An autogenerator is performed on the transistor Q1, the frequency of which is mainly determined by the characteristics of the TF1 pulsed transformer used here. Resistor R3 sets the mode of operation of the transistor Q1. Stabilization of the output voltage occurs due to the use of the feedback of the feedback of the pulse transformer TF1 and the chain D7 C4 ZD1. The transistor Q2 and the R2 resistor serve to limit the current of the transistor Q1 at the time of starting the autogenerator, as well as in case of overload or short circuit at the device output. The scheme contains a single-alpidative output voltage rectifier on Diode D8 and C5 condenser. The R6 resistor serves to discharge C5 condenser after turning off the device.

As a result of the verification of the charging device described above, a faulty transistor Q1 was found with marking 1003 and a burnt resistor R3. The burnt coating of the resistor did not allow to determine its resistance. In order to increase the reliability of the scheme, a more powerful and widespread domestic transistor Kt 940A was used as a transistor Q1 (Fig. 4). It should be noted that due to the large variation of the characteristics of CT 940A transistors in some cases, it may be necessary to change the resistance value of R3 specified in the diagram.

It should be noted that on the board, in the place provided for this, there is no oxide capacitor C, which must be connected at the output of the diode rectifier D1-D4. In this case, the auto-generator of the device actually operates in modulation mode with a straightened network voltage. For this reason, in many cases, such devices may not provide the claimed output current required to charge the mobile phone battery. The consequence of this may be, for example, an increase in total charging time. If necessary, you can set this missing condenser - its container can be no more than 10 μF for working voltage at least 450 V. It is recommended immediately with the installation of the capacitor soldered parallel to its legs on the installation side resistor with a resistance of about 300 com (for the discharge of this capacitor after disconnecting the device from network). In addition, for reliability, it is desirable to use a R1 resistor with a greater dissipation power, as it limits the charging current of the above capacitor at the time of turning on the device to the network. The board provides a place for the LED intended to indicate the operation of the device and, if necessary, it can be installed on a fee through a current-limiting resistor resistance of 680 ohms.

After repair, this charger works reliably for more than a year without comments. Given that the converter scheme used is widely used in many chargers, the described method of repair and improve reliability can be recommended for other similar devices.