The power supply is the first to meet the threat in the form of voltage surges, taking on all the consequences of instability in general, household power grids. It is known to be pretty typical problem modern domestic reality. According to statistics, it is the voltage drops or surges in household electrical networks that are the main cause of power supply malfunctions.
In second place are the problems of network adapters caused by a faulty laptop battery, the malfunction of which leads to a change in the limited loads on the power supply circuit and subsequently to its breakdown.
Finally, the fact that the laptop power supply is an external device leads to the fact that it is often disabled by purely physical impact. Non-compliance temperature regime environment around the unit, careless attitude to the on / off processes, kinking or twisting of wires, mechanical damage of various kinds - not only disables the adapter, but is simply unsafe for health, and in some cases, life!
Repair of a laptop power supply, the price of which is not high, should be done without delay!
Power supply failure symptoms
The following signs may indicate that something is wrong with your laptop and the reason for this, most likely, in the network adapter:- Without apparent reasons your laptop stops turning on.
- Spontaneous shutdown of the laptop after a short period.
- Increase in battery charging time or its complete absence.
- Unusually high heating of both the power supply itself and any of the connections in the mains connection circuit.
- The operation of the power supply varies depending on the location of the wires or the adapter case itself.
It is important to remember that a failed power supply can lead to much more serious problems, to eliminate the consequences of which you will have to fork out quite seriously!
Therefore, if you suspect a malfunction, network adapter or peripheral equipment, you should immediately make a thorough diagnosis and subsequent repair.
Diagnostics, repair or replacement
The decision about whether you will repair the laptop power supply with your own hands or contact the service center specialists for help can be made after the initial inspection of the device at home.Let's say if the cause of the malfunction is determined visually as mechanical damage wires, then it can, in principle, be eliminated with minimal skills in working with a soldering iron and electrical wiring.
In the case of an unobvious malfunction, it is reasonable, in our opinion, to contact a specialist. Full diagnostics of damage to internal elements and circuits requires special equipment, which is in service centerbut is unlikely to be available to the average user.
Another argument, and quite serious, in favor of contacting the service masters is the identity of the replacement of the original block, if it cannot be repaired.
First, you are unlikely to find an exact copy of a failed power supply. Choosing a model that is as close as possible in parameters to the original is often not an easy task - there are too many nuances to consider:
- All manufacturers make power supply connectors for themselves. As an exception, you can name the "laptops" Acer and Asus. However, even here a surprise may await you, the constructive connectors may be the same, but their polarity is reversed! Hence the advice, buy a new power supply with a laptop with you. This way you will avoid wasting money!
- It is necessary to pay attention to such characteristics of the block as: input and output voltage or input / output. If with the input voltage in our country everything is more or less stable - 220 volts, less often 150, but for most adapters this is not the limit of the operating range and they cope with it perfectly, then the output is more difficult.
- When choosing a model with characteristics close to the original, you should strictly adhere to the characteristics specified by the laptop manufacturer. The output voltage can differ up or down within 1-2 units. As an example: a 19.5 volt power supply will cope with the task and, if necessary, 18-21 volts.
- Current strength! If it is necessary to replace it, take a unit with an amperage identical to the original or greater. Otherwise, you will have to regularly buy a new adapter instead of a burnt out one, and this will not add "health" to a laptop. A power supply unit with a higher rating will cost, of course, more, but such a purchase can be considered as a one-time investment for a long time problem solver stable power supply to your laptop.
- Finally, the internal laptop power supply, the repair or diagnostics of which is a more difficult task than external inspection or soldering external device... Here the service center is definitely a priority!
Service centers, of course, make a mark-up on new parts offered for replacement, but it is not as significant as in stores. In addition, you get high-quality diagnostics and the most accurate match of the performance characteristics of the new unit.
The ordinary laptop power supply is very compact and quite powerful pulse unit nutrition.
In the event of a malfunction, many simply throw it away, and for replacement they buy a universal PSU for laptops, 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 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 worked, which was clear from the presence of a green LED indication. The voltage at the output plug corresponded to what is 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 up, 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 electronic components.
Then we take a flat screwdriver with a wide edge, insert it into the kerf and crack the halves of the case. 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 fastened 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 seeped 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 condenser was dismantled, its outer shell crumbled. Apparently 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 capacitor.
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, the temperature inside it can be very high.
Long-term heating has a very bad effect on the reliability of electrolytic capacitors. Therefore, I installed a Jamicon capacitor with a capacity of 68 μF * 450V, which is designed for working temperature up to 105 0 C.
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 power supplies from laptops, 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 tight enclosure proved to be a daunting task. Therefore, it was decided to install a product that is suitable in 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 pin connections! 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 you turn on for the first time after repair, keep your 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 changing 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 well electricity... 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 turned out that the remaining electrolyte under the throttle closed the circuit. The fuse has blown 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 here's what's inside him. 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 burn out. So in which case our self-made fuse will do its job. Of course, you can do with a thin wire jumper by soldering it to the contact nicks 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, it can lead to lead corrosion in the future. A good 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 laptop power adapters that I have been repaired.
Let's go back to our power supply. After cleaning from electrolyte residues and replacing the capacitor, you must check it without connecting 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 cooling heatsink of the power supply consists of several 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 soldered to the PCB, usually in one or two places. Between her and printed circuit board a plastic insulating plate is placed.
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 thermo gun, I cut off pieces of hot melt glue from the tube with a knife and put them in the grooves. After that, he took a hot air soldering station, set the degrees to about 200 ~ 250 0 C. Then he heated pieces of hot 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 faults.
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 inductor output line filter... Here is a photo.
It would seem that this is a trifling matter, 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.
You probably already noticed that large-sized elements, like the same electrolytic capacitor, filter chokes and some other parts, are smeared with something like 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 dump 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 ~ 90W.
Unfortunately, in case of more serious malfunctions, such as failure electronic components on a printed circuit board, the repair is complicated by the fact that it is quite difficult to find a replacement for the same PWM controller chip.
I can't even 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 should be noted that the overwhelming majority of laptop power adapters are made of very high quality. This can be seen at least by the presence of coil 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 not be present at all.
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 laptop acer... 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 here, so we'll break it! To do this, you will 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 gap formed and with force we draw along the contour of the connection of the halves of the case, gently breaking it along the seam.
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 have to repair the power supply cord to the laptop. Most often, a break occurs at the place 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 half. And so he did.
We solder back the connectors and test. Everything worked - the repair is over.
It remains only to glue the halves of the case with glue "moment" and give the power supply. The entire BP repair took no more than an hour.
We came to a cafe, took out a laptop to show our friends vacation photos. An unpleasant surprise: the laptop does not turn on, although it was charged for several hours. Does the situation sound familiar? My first thought is that my laptop is broken. Do not rush to jump to conclusions, check. We will tell you how to do this, and computer professionals - experts from the Batterion company - will help us.
What does a laptop charger consist of?
Before checking the adapter, you need to find out what elements it consists of. Components of the charger:
- Cable with a plug (plugged into a socket).
- The power supply is the "heart" of the charger. Electronic "filling" packed in a rectangular plastic case.
- Cord with connector (plugged into the laptop connector).
If at least one of the elements is damaged, charger will fail or will not work correctly.
The laptop won't charge: look for the real reason
First you need to exclude extraneous reasons, perhaps the power supply has nothing to do with it.
First, check the voltage and health of the outlet. To do this, you need to turn on an accurately working device (table lamp, hairdryer, mobile phone). Another option is to plug the laptop into a different, apparently working outlet. The voltage is 220V and the outlet is in perfect order - let's move on.
Remove the battery from the laptop and connect the power supply to the power supply and turn on the laptop. The computer is working, the indicator on the taskbar shows the operation of the mains, which means that everything is in order with the charger. Battery problem. If the laptop does not charge through the adapter, proceed to inspect this device.
What breaks in the charger - visual inspection
Sometimes it is enough to carefully examine all parts of the adapter to see damage. Let's start with the cable: the plug must be intact, the metal "horns" are even, do not stagger, the plug is not melted. Feel the cord - it should be even, without breaks, cracks, protruding wires and kinks. Found a defect - change the cord. You can find a suitable cable at a store or service center.
A damaged connector is the most common cause of adapter failure. The plug itself or the socket in the laptop can break. The plug is dangling in the connector, the wires are bare, the connector is cracked - you cannot use the power supply, you need to repair or replace a part.
The turn came to the "black box" - the power supply unit. You can even smell it: you hear the smell of burnt wiring or plastic - it's bad. And if you see melting on the case, it is better to immediately look for a new one laptop charger... Repair in this case is impractical, say the computer experts. Batterion specialists will help you choose a high-quality device that is 100% suitable for your laptop.
Multimeter - an irreplaceable "diagnostician"
When no external damage is found, the socket and the battery are intact, a multimeter, a special electrical measuring device, will help to determine the "diagnosis". If the tester is not in the house, you can take it for a day from friends or buy it at any radio store. The device is inexpensive and lasts for decades.
How to check the power supply with a multimeter:
- Connect the charger to the mains.
- Connect the tester terminals to the connector. Insert the red wire inside the plug, and attach the black wire with a metal tip from above. The power supply is definitely faulty when the voltage on the multimeter screen does not stabilize, constantly deviating to the side by 2-3 Volts. In this case, experts definitely advise replacing the device.
- Another option: the tester does not show voltage at all. So, you need to check the cord - it does not supply current to the power supply. Switch the multimeter to special mode, attach the terminals to the opposite ends of the cable. Have heard sound signal - the wire is serviceable. Silence in response indicates damage to the contacts inside the cable. Change the cord - it's cheaper than new laptop charger.
You need to carry out diagnostics as soon as possible, because lithium ion batteries cannot be in a discharged state for a long time. Only 10-14 days of forced "idle time" of an empty battery, and it can be thrown away - the capacity is irretrievably lost. Do not want to spend money on new battery - urgently solve problems with the power supply.
Adapter, battery and keyboard - these are the most common laptop parts that fail. You need a high-quality replacement of components for your laptop - contact the professionals! A careful attitude to the laptop, competent diagnostics and prompt problem solving are the main conditions for a long laptop operation!
The article was prepared based on materials from the site http://batterion.ru/
