In detail: do-it-yourself hp power supply repair from a real master for the site my.housecope.com.
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 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.
Next, 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.
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Video (click to play). |
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 was doing test turns. After a couple of connections to the 220V network, something crackled inside the block 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" that it 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 mains filter circuit. Here is a photo.
It would seem that the matter is trifling, I rewound the coil and sealed it in 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.
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.
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.
HP ppp012L-s 19V 4 / 74A power supply available
it is 3-pin: 19v, ID, Ground. Shim LTA301N, I could not find a datasheet for it
Initially came with a short circuit between the ID and GND pins in the layers of the cable leading to the laptop. The damaged section of the cable was cut off, the short circuit was gone, but the laptop still does not want to be powered from this unit early. I suppose the case is in the ID chain, where the closure was. Help advice on what and where to look.
19 -> gnd 0kom
Id -> gnd 0 kom, off 200kom and growing
19 -> id 298kom
Id goes from + 19V through a 300kom resistor, a transistor, a resistor and a diode are still connected in parallel with this resistor (in series)
Does the laptop work with another power supply unit?
It is hardly a transistor. For example, Dell has a chip with an identification code.
The cat has 4 legs. Entry, exit, ground and food.
YES. When you connect a defective power supply unit, the laptop turns on and charges the battery.
I study! 
Well, then we need to look for this microcircuit.
The cat has 4 legs. Entry, exit, ground and food.
Or you can try to pick up the resistance with a trimmer. But it could be hemorrhoids.
Someone picked it up for Dell.So it worked with 5kom as I remember.
I can't measure it yet: yesterday there was a laptop with such a power supply unit under repair, but it was already taken away. New such power supplies from China will come only in 2 weeks.
There are tools: DSO-5200A oscilloscope, Victor VC9805A + multimeter, ESR meter, Saike 898D soldering iron, there is access to a licensed PC-3000 for Win and Achi IR-PRO-SC BGA rework station.
and maybe someone has such a working block - measure how much it comes out on the central pin (ID)? I don't even have anything to measure on now.
I study!
I came across such power supplies quite often. The outer pin of the connector is ground, the next is V +, and the center is ID. On the ID in different power supplies, the voltage was from 14V to ((V +) - 0.3..0.6V). You have most likely confused center wiring with V +. Change.
the fact of the matter is that the wires are all soldered exactly as it should. I already have 2 such blocks with the same symptoms. I broke my whole head with them already.
Maybe someone has a schematic diagram of this block? I will be grateful.
I study!
I would be glad to help. There is no such thing.
When I have a laptop for repair with such a power supply, I will definitely try it on.
And what? the board can not be tracked ??
After all, the Chinese have already tracked and rivet the left power supply units only in the noise!
There are tools: DSO-5200A oscilloscope, Victor VC9805A + multimeter, ESR meter, Saike 898D soldering iron, there is access to a licensed PC-3000 for Win and Achi IR-PRO-SC BGA rework station.
Such blocks have just arrived from Uncle Liao's barn.
On center pin + VCC
But if you touch the probe, it drops to about + 10.5V. The resistance of my hand is now about 1MΩ.
I checked it with an oscillator - silence.
In short, I had to sort it out in order to help the questioner.
I attach the diagram: rom.by/files/HP_laptop_3pin_power_supply_DV4_DV5_DV7.rar
This circuit fits the following PSUs:
384020-001, 384021-001, 384020-003, 391173-001, 409992-001, ED495AA, PA-1900-18H2, PPP014L-SA,
382021-002, PPP012L-S, PPP012S-S, PPP014L-S, PPP014H-S, PA-1900-08H2, HP-AP091F13LF SE,
ED495AA # ABA, 397823-001, 416421-001, 418873-001, 463955-001
HP 2133 Mini-Note PC
HP 2533t Mobile Thin Client
HP Compaq 2230s Notebook PC
HP Compaq 2510p Notebook PC
HP Compaq 2710p Notebook PC
HP Compaq 6510b Notebook PC
HP Compaq 6515b Notebook PC
HP Compaq 6530b Notebook PC
HP Compaq 6535b Notebook PC
HP Compaq 6710b Notebook PC
HP Compaq 6715b Notebook PC
HP Compaq 6720t Mobile Thin Client
HP Compaq 6730b Notebook PC
HP Compaq 6730s Notebook PC
There are tools: DSO-5200A oscilloscope, Victor VC9805A + multimeter, ESR meter, Saike 898D soldering iron, there is access to a licensed PC-3000 for Win and Achi IR-PRO-SC BGA rework station.
Laptop power supplies. Scheme.
Schematic diagrams of laptop power supplies
Any craftsman who is faced with the repair of electronic equipment is faced with difficulties due to the lack of schematic diagrams, and it is not always possible to find the one you need on the Internet.
In this article, we want to share with you the schematic diagrams of some power supplies for laptops, for sure they will be useful when repairing these devices.
The following image shows a schematic diagram of a Chinese-made power supply unit China Hp 19V 3.16A:
Schematic diagram of the power supply unit of the laptop LITEON 19V 3.42A:
Schematic diagram of the power supply unit of the laptop ADP-90SВ VV 19V 4.74A:
Schematic diagram of the power supply unit of the laptop ADP-36EN 12V 3A:
The following diagram of the DELL PA-1900-02 SMPS ADAPTÖR 19.5V 4.62A power supply unit:
And one more power supply circuit, unfortunately its brand is not known, but maybe someone will come in handy:
We hope you find this article helpful. An archive with diagrams is available for download.
More notebook power supply diagrams in the articles:
If your computer's power supply fails, do not rush to get upset, as practice shows, in most cases, repairs can be done on your own. Before proceeding directly to the technique, we will consider the block diagram of the power supply unit and provide a list of possible malfunctions, this will greatly simplify the task.
The figure shows an image of a block diagram typical for pulsed power supplies of system units.
Switching power supply unit ATX
Indicated designations:
- A - power filter unit;
- B - low-frequency rectifier with a smoothing filter;
- C - cascade of the auxiliary converter;
- D - rectifier;
- E - control unit;
- F - PWM controller;
- G - cascade of the main converter;
- H - high-frequency rectifier equipped with a smoothing filter;
- J - PSU cooling system (fan);
- L - output voltage control unit;
- K - overload protection.
- + 5_SB - standby power supply;
- P.G. - information signal, sometimes referred to as PWR_OK (required to start the motherboard);
- PS_On - signal controlling the start of the power supply unit.
To carry out repairs, we also need to know the pinout of the main power connector, it is shown below.
Power supply plugs: A - old (20pin), B - new (24pin)
To start the power supply, it is necessary to connect the green wire (PS_ON #) to any zero black wire. This can be done using a conventional jumper. Note that for some devices the color coding may differ from the standard one, as a rule, unknown manufacturers from China are guilty of this.
It should be warned that turning on impulse power supplies without load will significantly reduce their service life and may even cause damage. Therefore, we recommend assembling a simple block of loads, its diagram is shown in the figure.
Load block diagram
It is advisable to assemble the circuit on resistors of the PEV-10 brand, their ratings: R1 - 10 Ohm, R2 and R3 - 3.3 Ohm, R4 and R5 - 1.2 Ohm. Cooling for resistors can be made from an aluminum channel.
It is undesirable to connect a motherboard as a load during diagnostics or, as some "craftsmen" advise, an HDD and CD drive, since a faulty power supply unit can damage them.
Let's list the most common malfunctions characteristic of pulsed power supplies of system units:
- the mains fuse blows;
- + 5_SB (standby voltage) is absent, as well as more or less than the permissible;
- the voltage at the output of the power supply (+12 V, +5 V, 3.3 V) does not correspond to the norm or is absent;
- no P.G. signal (PW_OK);
- PSU does not turn on remotely;
- the cooling fan does not rotate.
After the power supply is removed from the system unit and disassembled, first of all, it is necessary to inspect for the detection of damaged elements (darkening, changed color, violation of integrity). Note that in most cases, replacing a burnt-out part will not solve the problem; a piping check will be required.
Visual inspection allows you to detect "burnt" radioelements
If these are not found, we proceed to the following algorithm of actions:
If a faulty transistor is found, then before soldering a new one, it is necessary to test its entire strapping, consisting of diodes, low-resistance resistances and electrolytic capacitors. We recommend changing the latter to new ones with a large capacity. A good result is obtained by shunting electrolytes using 0.1 μF ceramic capacitors;
- Checking the output diode assemblies (Schottky diodes) with a multimeter, as practice shows, the most typical malfunction for them is a short circuit;
Diode assemblies marked on the board
- checking the output capacitors of the electrolytic type. As a rule, their malfunction can be detected by visual inspection. It manifests itself in the form of a change in the geometry of the housing of the radio component, as well as traces from the flow of electrolyte.
It is not uncommon for an outwardly normal capacitor to be unsuitable during testing. Therefore, it is better to test them with a multimeter that has a capacitance measurement function, or use a special device for this.
Video: correct repair of an ATX power supply. <>
Note that non-working output capacitors are the most common malfunction in computer power supplies. In 80% of cases, after replacing them, the power supply unit's performance is restored;
Capacitors with disturbed case geometry
- the resistance is measured between the outputs and zero, for +5, +12, -5 and -12 volts this indicator should be in the range from 100 to 250 ohms, and for +3.3 V in the range of 5-15 ohms.
In conclusion, we will give some tips for improving the power supply unit, which will make it work more stable:
- in many inexpensive blocks, manufacturers install rectifier diodes for two amperes, they should be replaced with more powerful ones (4-8 amperes);
- Schottky diodes on channels +5 and +3.3 volts can also be supplied more powerful, but at the same time they must have an allowable voltage, the same or greater;
- it is advisable to change the output electrolytic capacitors to new ones with a capacity of 2200-3300 uF and a rated voltage of at least 25 volts;
- it happens that instead of a diode assembly, diodes soldered to each other are installed on the +12 volt channel, it is advisable to replace them with an MBR20100 Schottky diode or similar;
- if capacities of 1 μF are installed in the piping of key transistors, replace them with 4.7-10 μF, calculated for a voltage of 50 volts.
Such a minor revision will significantly extend the life of the computer power supply.
Very interesting to read:
I will tell you how to disassemble the Samsung SyncMaster 960BF monitor later. So, we have a power supply, the output of which has 14 volts of constant voltage and a maximum current of 3 amperes.
The plug of this power supply unit is made, we can say classically - the internal output is "+14 V", the external one is the common wire.
This is how it looks power supply seam monitor before disassembling.
Especially for the readers, I took off video of the disassembly process... This video is suitable for any glued power adapter for laptop, monitor, printer or other equipment. The main principle is to insert a sharp tool into the seam of the power supply and confident blows split it in two.
This is how it should look power supply seam after opening.
Taking out the board, I saw a characteristic darkening of the PCB, which indicates overheating elements on the board. 
As a result poor quality soldering at the factory - microcracks in the solder have formed. Because of this, the resistance of the "resistor-track" contact increased and it began to heat up more intensively, from which the microcrack expanded, because the mechanical strength of the solder, as is known, decreases with increasing temperature. First microcrack under the resistor. 
The second microcrack in the solder. 
The third crack was detected already at wobbling resistor, the leg of which is soldered to the board tracks at this point. 
Above the resistors are filled with some kind of rubber foam. It is possible that it worsens the heat transfer between the elements inside the power supply case.
We remove this glue and see overheated resistors... The paint even charred on them at the point where the metal leads were connected to the resistor case. 
We solder these resistors and change to the like. The resistor on the left is 33k ohms and the right is 33 ohms. 
I determined it by resistor marking table color coded ring. 
Soldering resistors in place and we do not regret solder and flux... Overheated pads of the PCB tracks do not hold the solder well. 
That's what happened from the side of radioelements.
Be sure to check condition of electrolytic capacitors, who are afraid of overheating. Just look at how flat the top is to make sure everything is okay. But if you change, then only for capacitors Rubycon 1000 uF 25 V and capacitors Nippon 2200 uF 25 V... There are cheaper of the decent ones (but always by 105 degrees) Samwha 2200 uF 25 V.
This completes the repair of the power supply. It remains to collect everything back into the case and check for stability. Now you can feel how carefully you disassembled the power supply case. If both halves converge with a seam width of about 1 mm, then everything is fine, if more, then plastic burrs along the seam may interfere. They need to be removed with a knife or side cutters.
As soon as we achieve a satisfying seam, drip a few drops (I usually drip at 6-8 points) onto the seam of "Second" type glue and press the body with something heavy for 5 minutes. Now everything is ready - repaired power supply unit SAD04214A from Samsung 960BF monitor and glued back after opening.
Happy renovation!
Your Solder Master.
Don't forget to check the C107 with a meter. In 90% of cases, either dried out or leaked.
Thanks for the addition. I completely agree.
Indeed, there was a problem in him - short circuit.
You never measure ESR at conductors, but in vain!
If I had something to measure, then I would measure it.And so, I just call for a breakdown. But Underzen is right, ideally ESR should be measured.
Good afternoon. Interesting site, thank you for sharing your best practices ...
Regarding the power supply unit in sealed cases (even "in forks"). Once they taught me, so I decided to share - your idea is correct, you need to open it at the seam with an eagerly strong knife, not very hardened, so as not to break. The main highlight is to put the PSU in the freezer for an hour or two. Frozen plastic very well then cracks along the seam, even strongly glued (due to inhomogeneity). Sometimes I even just tap the seam with a heavy hammer so as not to spoil the look. Naturally, the pause in the repair is delayed for the time of thawing and evaporation of moisture then, but the chldopot is less and the quality is better.
Second, people are right when they talk about ESR. A few years ago, life forced me to take up the repair of near-computer equipment just as hard. 99% of power supply units are already pulsed, their diagnostics using ESR sometimes turns into a routine, and not troubleshooting, hi! Here is a device that I have been using for a long time, I tried a bunch of everything and settled on this particular design. Run along the branch if desired. In general, in the dock at 1.01, everything is scheduled.
Thank you for your advice))) I will improve my skills))) Live and learn!
Good evening, comrades. I need your help! I am a happy owner of the samsung syncmaster 960bf monitor! The monitor holder is broken!
Epoxy "Second" to help you)))
Thanks! Do you think this will help?
Yes, if you degrease the surface of the plastic, sand it and reinforce it with metal, the epoxy will hold up well. I restored laptops this way.
Good morning Solder Master! I can send you a photo of my breakdown to understand what happened to me! Please drop me your email address!
Good afternoon. I need your help, I have a monitor 960, when the power is turned on, the power button on the monitor starts blinking, I noticed until the power supply unit warms up or you warm it up, the monitor does not turn on. What to do?
You need to fix the power supply. Disassemble and check capacitors and soldering. If it doesn't help, write.
Nice post. He himself was once fond of radio electronics. I have 5 stars and success in development!
Thank you Ivan. And good luck to you with your blog)))
Vyacheslav, there are two options - either the electrolytic capacitors are dry - replace them (start with a small 47 microfarad 50 V), or a microcrack has formed in the soldering - solder the board. The rest is unlikely.
Hello!
Today I replaced 4 capacitors (there seem to be only 4 of them).
The effect is "0".
It turns off anyway.
I went to the repair of laptops on the radio market. There, the cunning people directly said that the soldering of the condenders to one place. And they said they knew what was out of order there. But they flatly refused to tell me. Like: pay the money and we will repair it ourselves, and keep the condensers for yourself.
Can you advise on what forum to consult?
- external - common wire
- internal - +19 Volt
- central - id-signal.
With the first two, it is clear that the laptop is powered by them. But the third wire (central core) is needed to charge the laptop. And it works as follows: if there is no voltage on it, then the battery does not charge, and if there is a voltage of a certain value, then charging is turned on. The catch is that this denomination is not described anywhere, and the power supply itself is faulty.
As always, a way out was found on the Internet, on one of the forums. It turns out that Chinese homemade products have long figured out the HP circuitry, and they are making their own power supplies with this additional signal.
Here is the circuit for receiving this signal:
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Video (click to play). |
Part numbers on the diagram:
resistor: 330kohm (in SMD version it will say "334". This can be found on almost any unnecessary board)
capacitor: 100nF (thanks to the vigilant blog readers)
diode - any withstanding voltage of 20 volts (it is better to take 30-50 volts).
