In detail: do-it-yourself hp laptop charger repair from a real master for the site my.housecope.com.
When buying a laptop or netbook, or rather calculating the budget for this purchase, we do not take into account further associated costs. The laptop itself costs, say, $ 500, but another $ 20 bag, $ 10 mouse. The battery when replaced (and its warranty life is only a couple of years) will cost $ 100, and the same will be the cost of the power supply if it burns out.
It is about him that the conversation will go here. One not very wealthy friend recently stopped working the power supply for an acer laptop. You will have to pay almost a hundred dollars for a new one, so it would be quite logical to try to fix it yourself. The PSU itself is a traditional black plastic box with an electronic pulse converter inside, providing a voltage of 19V at a current of 3A. This is the standard for most laptops and the only difference between them is the power plug :). Immediately I give here several diagrams of power supplies - click to enlarge.
When the power supply is turned on, nothing happens - the LED does not light up and the voltmeter shows zero at the output. Checking the power cord with an ohmmeter gave nothing. We disassemble the case. Although it's easier said than done: there are no screws or screws provided here, so we'll break it! To do this, you need to put a knife on the connecting seam and hit it lightly with a hammer. Do not overdo it, or cut the board!
After the case is slightly parted, we insert a flat screwdriver into the formed gap and with force we draw along the contour of the connection of the halves of the case, gently breaking it along the seam.
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Having disassembled the case, we check the board and parts for anything black and charred.
The dialing of the input circuits of the 220V mains voltage revealed a malfunction - this is a self-healing fuse, which for some reason did not want to recover from an overload :)
We replace it with a similar one, or with a simple fusible one with a current of 3 amperes and check the operation of the power supply unit. The green LED lit up, indicating the presence of 19V, but there is still nothing on the connector. More precisely, sometimes something slips, as if the wire is bent.
We'll also have to repair the power supply cord to the laptop. Most often, a break occurs at the point where it is inserted into the case or at the power connector.
We cut it off first at the body - no luck. Now near the plug that is inserted into the laptop - again there is no contact!
A hard case - a cliff somewhere in the middle. The easiest option is to cut the cord in half and leave the working half, and discard the non-working one. And so he did.
We solder the connectors back and carry out the tests. Everything worked - the repair is over.
It remains only to glue the halves of the case with glue "moment" and give the power supply to the customer. The entire BP repair took no more than an hour.
I'll start with the background. One fine day an electrician came to my neighbors. And he climbed, for one reason known to him, with his crooked hands into my switchboard. As a result of his manipulations, 380V instead of 220V went to my apartment. Result: burned down everything that was included in the outlet. Namely: 2 chargers (Toshiba and HP) and power supply unit from 3G modem... Buy new chargers, giving $ 50 for each, I was sorry, so I decided to play with an electrician and a foreman. Actually repairing a charger from a laptop and it will be discussed further.
Well, a puddle, I solder, I fix the computer.
I just want to apologize for the quality of some of the pictures below - I photographed it with an iron.
Charger repair consider using the example of a device from HPbecause the second charger I am repaired before it fell into my hands camera iron.
That's actually itself charger from HP:
The first thing to do is open the charging case... The best way I could think of is to point a knife at the seam and hit it sharply with the handle of a screwdriver (you can also use a hammer, but I feel sorry for the knife).
The advantage of this method is that the edges of the halves of the case remain even and then they can be carefully glued together.
Opening the case, extract the filling. It is covered with metal plates. They need to be removed.
On the other hand, the plate will soldered.
We solder and remove the plates (my soldering iron is shit, so I just cut off the places with scissors solder).
Is now clearly visible charger malfunction - exploded big capacitorlocated in the middle. The drops that can be seen on the black plate - flowing out of capacitor electrolyte. The capacitor needs to be replaced. I'm for a new one (400V 100mF) gave about $ 2. By the way, in charger from Toshiba the fault was the same, but capacitor 420V 82mF... I did not find this, so I also put 400V 100mF... Everything is working.
And so, we need evaporate old capacitor... To do this, remove the black plate (when assembling, it is important not to forget it, because it insulates the contacts from the metal case).
White shit with which the entire board is stained, you need to carefully pick out in places soldering capacitor... Don't worry, this is just a sealant that held the black plate to the board. Rip off and we solder the capacitor.
Solder new capacitor (do not forget to look at the old capacitor where the + and - were. For those who do not know, there is a vertical strip on the condenser on the minus side.)
Now we collect everything as it was, push it into the body and glue the halves of the body. I used "Moment" for this.
Charger looks almost like new and great working.
An ordinary laptop power supply is a very compact and rather powerful switching power supply.
In the event of a malfunction, many simply throw it away, and buy a universal power supply unit for laptops for replacement, the cost of which starts from 1000 rubles. But in most cases, you can fix such a block with your own hands.
It's about repairing a power supply from an ASUS laptop. It is also an AC / DC power adapter. Model ADP-90CD... Output voltage 19V, maximum load current 4.74A.
The power supply itself was working, which was clear from the presence of a green LED indication. The voltage at the output plug corresponded to that indicated on the label - 19V.
There was no break in the connecting wires or breakage of the plug. But when the power supply was connected to the laptop, the battery did not start charging, and the green indicator on its case went out and glowed at half the original brightness.
It was also heard that the unit beeps. It became clear that the switching power supply was trying to start, but for some reason, either an overload or short-circuit protection was triggered.
A few words about how you can open the case of such a power supply. It is no secret that it is made sealed, and the design itself does not imply disassembly. For this we need several tools.
We take a manual jigsaw or a canvas from it. It is better to take the canvas on metal with a fine tooth. The power supply itself is best clamped in a vice. If they are not there, then you can contrive and do without them.
Then, with a manual jigsaw, we cut into the depth of the body by 2-3 mm. in the middle of the body along the connecting seam. The cut must be done carefully. Overdoing it can damage the circuit board or electronics.
Then we take a flat screwdriver with a wide edge, insert it into the cut and unclip the halves of the case. There is no need to rush. When separating the halves of the case, a characteristic click should occur.
After the case of the power supply is opened, we remove the plastic dust with a brush or a brush, we take out the electronic filling.
To inspect the elements on the printed circuit board, you will need to remove the aluminum radiator bar. In my case, the bar was attached to other parts of the radiator with latches, and was also glued to the transformer with some kind of silicone sealant. I managed to separate the bar from the transformer with a sharp blade of a pocket knife.
The photo shows the electronic filling of our block.
The fault itself did not take long to look for. Even before opening the case, I did test turns. After a couple of connections to the 220V network, something crackled inside the unit and the green indicator indicating work was completely extinguished.
When inspecting the case, a liquid electrolyte was found, which leaked into the gap between the network connector and the elements of the case. It became clear that the power supply unit ceased to function normally due to the fact that the electrolytic capacitor 120 uF * 420V “slammed” due to exceeding the operating voltage in the 220V power grid. Quite an ordinary and widespread malfunction.
When the capacitor was dismantled, its outer shell crumbled. Apparently it lost its properties due to prolonged heating.
The safety valve at the top of the housing is "swollen" - this is a sure sign of a defective condenser.
Here's another example with a faulty capacitor. This is a different laptop power adapter. Pay attention to the protective notch on the top of the condenser housing. It broke open from the pressure of the boiling electrolyte.
In most cases, bringing the PSU back to life is pretty easy. First you need to replace the main culprit of the breakdown.
At that time, I had two suitable capacitors at hand. I decided not to install a SAMWHA 82 uF * 450V capacitor, although it was ideally sized.
The fact is that its maximum operating temperature is +85 0 C. It is indicated on its body. And if you consider that the power supply case is compact and not ventilated, then the temperature inside it can be very high.
Long-term heating is very bad for the reliability of electrolytic capacitors. Therefore, I installed a Jamicon capacitor with a capacity of 68 μF * 450V, which is designed for operating temperatures up to 105 0 С.
It is worth considering that the capacity of the native capacitor is 120 uF, and the operating voltage is 420V. But I had to put in a capacitor with a smaller capacity.
In the process of repairing laptop power supplies, I encountered the fact that it is very difficult to find a replacement for the capacitor. And the point is not at all in the capacity or operating voltage, but in its dimensions.
Finding a suitable capacitor that would fit into a cramped case proved to be a daunting task. Therefore, it was decided to install a product of suitable size, albeit a smaller capacity. The main thing is that the capacitor itself is new, of high quality and with an operating voltage of at least 420
450V. As it turned out, even with such capacitors, the power supplies work properly.
When sealing a new electrolytic capacitor, you must strictly observe the polarity connect the pins! Typically, the PCB has a “+" or "–“. In addition, a minus can be marked with a black bold line or a mark in the form of a spot.
On the negative side of the capacitor case, there is a mark in the form of a strip with a minus sign “–“.
When turning on for the first time after repair, keep a distance from the power supply, because if the polarity of the connection is reversed, the capacitor will "pop" again. This can cause the electrolyte to get into the eyes. This is extremely dangerous! Wear protective goggles if possible.
And now I’ll tell you about the “rake”, which is better not to step on.
Before you change anything, you need to thoroughly clean the board and circuit elements from liquid electrolyte. This is not a pleasant occupation.
The fact is that when an electrolytic capacitor slams, the electrolyte inside it breaks out under great pressure in the form of splashes and steam.It, in turn, instantly condenses on the nearby parts, as well as on the elements of the aluminum radiator.
Since the installation of the elements is very tight, and the case itself is small, the electrolyte gets into the most inaccessible places.
Of course, you can cheat and not clean out all the electrolyte, but this is fraught with problems. The trick is that the electrolyte conducts electric current well. I was convinced of this from my own experience. And although I cleaned the power supply very carefully, I did not begin to solder the choke and clean the surface under it, I hurried.
As a result, after the power supply was assembled and connected to the mains, it worked properly. But after a minute or two, something crackled inside the case, and the power indicator went out.
After opening it, it turned out that the remaining electrolyte under the throttle closed the circuit. The fuse has blown because of this. T3.15A 250V on the input circuit 220V. In addition, in the place of the short circuit, everything was covered with soot, and the wire of the choke burned out, which connected its screen and the common wire on the printed circuit board.
The same choke. The burned-out wire was restored.
Soot from a short on the printed circuit board just below the choke.
As you can see, it jumped out decently.
The first time I replaced the fuse with a new one from a similar power supply. But when it burned down a second time, I decided to restore it. This is what the fuse on the board looks like.
And this is what he has inside. It can be easily disassembled, you just need to squeeze the latches at the bottom of the case and remove the cover.
To restore it, you need to remove the remnants of the burnt wire and the remnants of the insulating tube. Take a thin wire and solder it in place of your own. Then assemble the fuse.
Someone will say that this is a "bug". But I disagree. In the event of a short circuit, the thinnest wire in the circuit burns out. Sometimes even the copper tracks on the PCB will burn out. So in which case our self-made fuse will do its job. Of course, you can also do with a thin wire jumper by soldering it to the contact dimes on the board.
In some cases, in order to clean out all the electrolyte, it may be necessary to dismantle the cooling radiators, and with them active elements such as MOSFETs and dual diodes.
As you can see, liquid electrolyte can also remain under coil products, such as chokes. Even if it dries out, in the future, due to it, corrosion of the leads may begin. An illustrative example is in front of you. Due to electrolyte residues, one of the capacitor leads in the input filter completely corroded and fell off. This is one of the power adapters from the laptop that I have been repaired.
Let's go back to our power supply. After cleaning it from electrolyte residues and replacing the capacitor, it is necessary to check it without connecting it to a laptop. Measure the output voltage at the output plug. If everything is in order, then we assemble the power adapter.
I must say that this is a very time-consuming business. First.
The PSU cooling heatsink consists of multiple aluminum fins. Between themselves, they are fastened with latches, and are also glued with something resembling a silicone sealant. It can be removed with a pocket knife.
The upper radiator cover is fastened to the main part with latches.
The bottom plate of the heatsink is fixed to the PCB by soldering, usually in one or two places. A plastic insulating plate is placed between it and the PCB.
A few words about how to fasten the two halves of the body, which at the very beginning we sawed with a jigsaw.
In the simplest case, you can simply assemble the power supply and wrap the halves of the case with electrical tape. But this is not the best option.
I used hot melt glue to glue the two plastic halves together. Since I don't have a thermal gun, I cut off pieces of hot melt glue from the tube with a knife and put them in the grooves. After that, I took a hot air soldering station, set about 200 degrees
250 0 C. Then he heated pieces of hot melt glue with a hair dryer until they melted.I removed the excess glue with a toothpick and once again blew it with a hairdryer on the soldering station.
It is advisable not to overheat the plastic and generally avoid excessive heating of foreign parts. For me, for example, the plastic of the case began to brighten with strong heating.
Despite this, it turned out very soundly.
Now I will say a few words about other malfunctions.
In addition to such simple breakdowns as a slammed capacitor or an open in the connecting wires, there are also such as an open circuit in the choke output in the line filter circuit. Here is a photo.
It would seem that the matter is trifling, I rewound the coil and sealed it into place. But it takes a lot of time to find such a malfunction. It is not possible to detect it immediately.
Surely you have already noticed that large-sized elements, like the same electrolytic capacitor, filter chokes and some other parts, are smeared with something like a white sealant. It would seem, why is it needed? And now it is clear that with its help large parts are fixed, which can fall off from shaking and vibrations, like this very choke, which is shown in the photo.
By the way, initially it was not securely fixed. Chatted - chatted, and fell off, taking the life of another power supply from the laptop.
I suspect that thousands of compact and rather powerful power supplies are sent to the landfill from such banal breakdowns!
For a radio amateur, such a pulsed power supply with an output voltage of 19 - 20 volts and a load current of 3-4 amperes is just a godsend! Not only is it very compact, but also quite powerful. Typically, the wattage of power adapters is 40
Unfortunately, in case of more serious malfunctions, such as failure of electronic components on a printed circuit board, repair is complicated by the fact that it is rather difficult to find a replacement for the same PWM controller microcircuit.
It is not even possible to find a datasheet for a specific microcircuit. Among other things, the repair is complicated by the abundance of SMD components, the marking of which is either difficult to read or it is impossible to purchase a replacement element.
It is worth noting that the overwhelming majority of laptop power adapters are made of very high quality. This can be seen at least by the presence of winding parts and chokes that are installed in the network filter circuit. It suppresses electromagnetic interference. In some low-quality power supplies from stationary PCs, such elements may be absent altogether.
In fact, a laptop power supply and charger consists of two parts - a battery supply unit (it also contains a charging control system) and an external charger, which is usually a switching power supply with an output voltage of 19V. It is about this, external, part that will be discussed in this article. An example of a power supply circuit for Acer notebooks with an output voltage of 19V at a maximum current of 3.5A is shown in the figure. It should be noted that power supplies for other laptops are built according to a similar scheme, so the material described in this article can be used when repairing power supplies for a variety of laptops, and in general switching power supplies.
And so, the power supply is made according to a pulse circuit and is based on the TOP258EN (U1) microcircuit from Power Integrations. This microcircuit has a built-in controller and a power MOSFET switch, which it controls by changing the width of the pulses arriving at its gate, based on the feedback signal.
The mains voltage is fed through fuse F1 and extra-current protection on the power thermistor RT1 to the input choke L1, which suppresses interference. This is followed by a bridge rectifier on diodes D1-D4. During normal operation, a constant voltage of about 305V is released on the capacitor C4. This voltage powers the pulse generator based on the U1 microcircuit and the T1 pulse transformer.
Resistors R3 and R4 create the starting supply voltage of the U1 microcircuit, which is necessary for the initial start of its generator at the moment of power-on.The generator starts up and gives the first pulses to the gate of the key transistor of the microcircuit. At terminal D U1, powerful current pulses appear, which flows through the primary winding of the transformer T1. This leads to voltage induction in the secondary windings. The T1 4-5 winding is used for the working power supply of the microcircuit, to which the microcircuit switches after a successful start of the unit. The rectifier consists of a diode D6 and a capacitor C10. If the start-up is normal, then the VR2 zener diode opens and through it, power is supplied to the U1 controller. The controller now switches from run mode to operating mode.
To monitor the state of the circuit, the controller of the U1 microcircuit has two inputs - C and X. Input X is used to monitor the value of the mains voltage. The mains voltage value sensor is a divider across resistors R1, R2 and R9. The magnitude of the mains voltage is estimated by the magnitude of the voltage across the resistor R9. Input C is used to monitor the state of the output. A phototransistor of the optocoupler U2 is connected between it and the rectifier on diode D6, and its LED is connected to the secondary circuit (to the output of the rectifier on diodes D7, D8 and capacitor C 13 through IC U3, which controls the output state).
Here is a short description of how the power supply works. Now let's move on to the "typical" problems.
1. The unit does not work, we turn it on, but there is no voltage at the output, no sounds, no chirping either. The most common malfunction. There may be a malfunction both at the input and at the output (we will not talk about a banal break in the power cord or output cord), or in the generator pulse itself.
So, if the power supply does not work, and the fuse F1 is intact, then it is best to start troubleshooting by checking the voltage at the output of the mains rectifier.
This voltage should be about +305 V (in any case within the range of 280-310V), with an AC supply voltage equal to 220 V. In addition, use an oscilloscope to check the amplitude of the ripple of this voltage. If the voltage is significantly lower than the above value or not at all, check the mains voltage rectifier. An increased amplitude of ripple at a reduced voltage indicates a malfunction of the capacitor C4 or an open circuit in the diode rectifier on diodes D 1-D4.
The complete absence of voltage at C4 indicates an open circuit in the circuit from the mains plug to C4. It is very possible that RT1 or bridge diodes burned out, choke L1. But if the fuse is still intact, then the malfunction may be in a banal soldering defect (some terminal in this circuit is loosened, damaged by corrosion), a crack in the printed track. Disconnect from mains and find fault by continuity test.
If the fuse blows out, it makes sense to restart it by connecting the power source to the network through a 220V incandescent lamp with a power of at least 100W. This will secure the other parts of the circuit that the fuse saved. For example, in case of a short circuit in C4, when re-connected to the network, the fuse may not have time to operate, which will damage the rectifier diodes, choke windings, etc.
And the incandescent lamp will limit the short circuit current.
A blown fuse (or breakdown of rectifier diodes, resistor RT1) is most likely associated with a breakdown (in-between closure) of the capacitor C 4. An additional sign of a capacitor breakdown may be a change in the shape of its case (swelling of the bottom, its rupture). Less commonly, this is due to the breakdown of the transistor of the U1 microcircuit.
You should be aware that the breakdown of a powerful switching transistor of a microcircuit is not necessarily spontaneous, but is often caused by a malfunction of some other element. In particular, in the considered circuit, this may be an open circuit of one of the elements of the damping circuit D5, R6, C6, VR1, R7, as well as the presence of short-circuited turns in the primary winding of the transformer T1.
Therefore, before replacing the microcircuit in the event of a breakdown of the output transistor, it is advisable to analyze the possible causes of its failure and carry out the necessary checks, otherwise, to eliminate the malfunction, you will have to stock up on a large number of expensive, powerful transistors.
In addition, there may be an inter-lining closure SZ. However, only the fuse will blow.
If there is a voltage of + 305V on C4, this indicates that the primary rectifier circuits are in good order and the inoperability of the power supply may be associated with a malfunction in the generator on the IC U1 and the transformer T1.
The power supply may simply not start when turned on due to an open circuit in the resistors R3-R4. In this case, when switched on to the network, power is not supplied to the generator of the IC U1, and it does not work. Another case is an open circuit in the output key of the microcircuit.
The most rare case is a break in the transformer windings, in particular the primary winding. In this case, the power supply does not work at all. This can be determined by measuring the constant voltage at terminal D of the U1 microcircuit. If there is no voltage of 305V on it, but there is no voltage on C4 (the filter capacitor of the mains rectifier), then, most likely, the primary winding of the pulse transformer is cut off (in this circuit, the winding of 1-3 of the transformer T1) ...
Although you should not exclude a break in the printed tracks or poor-quality solders. Before deciding to replace the transformer, it is necessary to find out whether the cause of this break was a short circuit in the primary winding circuit, for example, a breakdown of the output transistor U1 (it should not ring in both directions between terminals D and S of U1).
An emergency state of the unit is possible due to a short circuit in the secondary circuit. Either the erroneous state of the secondary circuit monitoring system due to damage to U3 or in the elements of its "strapping". A short circuit in the secondary circuit most often occurs due to the breakdown of one of the electrolytic capacitors.
The ripple of the power supply (short-term start when connected to the network, without switching to operating mode) can be caused by a malfunction in the rectifier circuit at D 6, C 10, as well as the VR2 zener diode.
Often in technology, the power adapter breaks down. Typically, a laptop power supply becomes unusable due to improper use or a sharp jump in the voltage amplitude in the power supply. If you find that there is a lack of power in this charging component, then you can immediately use the services of a service center or even buy a brand new device for yourself. Both options are unlikely to cost you cheap, and who likes the extra costs? You can try to restore the former performance of the power supply yourself. Let's take a look at the step-by-step repair of a laptop power supply today and pay attention to the main nuances. Before taking up the tools and getting down to work, you should evaluate your abilities in this area several times. Important! If you do not have basic skills in working with electrical appliances, we recommend that you refuse to repair the power supply unit at home. Without proper understanding, you can do more harm to the component, as well as your health! You can immediately identify several of the most common types of malfunctions: If any of the points are familiar to you firsthand, then you can familiarize yourself with repairing a laptop power supply with your own hands step by step and take the initiative into your own hands. If you have ever held a soldering iron in your hands and know how to read at least a little electrical diagrams, then you can safely take on the restoration work of the adapter. Let's take a look at two of the most common causes of breakdowns. Do-it-yourself laptop power supply repair is carried out as follows: Important! If you think that this procedure is very complicated, then we do not recommend that you take on the work yourself. Better get a new adapter. How to fix a laptop power supply if all the components inside the case are working properly? You can find the answer below. The cord that comes from the power supply often suffers from various mechanical influences. If the problem lies in the wiring, then you can resort to the following instructions for carrying out restoration work: Important! If you want to use the latter, we recommend that you put this component on your cord in advance. back to content ↑
