How to desolder a microcircuit from a board with a soldering iron. How to solder SMD chips. Soldering station. Ideal tool for soldering chips

Doing renovations household appliances A home craftsman is quite often faced with the need to replace electronic components located on circuit boards or mounted using a hinged method.

In this case, you must work carefully, otherwise you can damage the semiconductor layer, burn out the tracks, or even destroy the case.

In order to solder a transistor, microcircuit or diode, you need to know and follow certain installation rules. Read them in this article.

Principles of safe work with semiconductor radio components

Temperature conditions

All electronic devices are designed to operate at normal temperatures. They cannot withstand overheating for a long time and do not respond well to pulsed temperature influences: the semiconductor junction fails, contacts are broken, and the housing of the radio component is depressurized.

However, the main methods of their installation remain welding or soldering, which ensures the heating of the contact pads and their connection when cooling.

The brands of low-melting solders used, such as POS-60 or POS-40, begin to transform into a liquid state when heated to 183 degrees, and when cooled in air, they quickly cool down and create reliable contact.

The safety of the transistor, diode, microcircuit, capacitor is ensured due to the short time of melting and hardening of the solder on the leg of the radio component.

Board design

To ensure safe soldering, you should imagine the design of the board on which the radio component is attached. In practice, the most common models are with:

one;
or two layers of copper foil conductors onto which solder is applied.

They are glued onto dielectric plates made of fiberglass or getinax.

In addition to these models, special high-precision electronic devices use multilayer boards with a complex arrangement of conductive paths of various designs.

Installation of parts on them by soldering, using solder, is carried out by robots in a factory environment.

For the home handyman It is quite difficult to do such work efficiently at home.

Necessary tool

Soldering iron

Old models

A properly selected soldering iron can ensure normal heating of the contact tracks of boards and semiconductor leads.

The old EPSI model of the “Moment” type with a power of 65 watts has a universal design. Its not difficult.

Previously, resistive type models with a heating element made of thin nichrome wire were widely used.

Modern soldering irons

For specific soldering conditions, you can now purchase various types of models equipped with all sorts of functions.

For example, a soldering iron with tin suction has been specially designed for soldering microcircuits, transistors and diodes.

It quickly heats up a layer of solidified solder and easily removes it in a liquid state from the contact pad.

Radio component holders

When heating the transistor leg for tinning and soldering, you should always remove the heat from the body and semiconductor layer with some metal object.

For this purpose, tweezers or alligator clips are usually used. However, it is most convenient to work with a medical instrument with thin legs, which surgeons use during operations.

Fixing electronic boards

Radio components and boards are usually small in size and require reliable fixation in space. Soldering them while hanging is dangerous: a small wrong movement can damage the entire structure.

When working with them, one hand is already occupied: it contains a soldering iron. And the second one needs to perform some additional actions. In this case, factory or homemade vices, holders, and clamps come to the rescue. They must be used.

At the moment the solder melts, they are inserted inside the board sleeve to separate the leg of the radio component from the contact track.

A home craftsman can buy a ready-made kit in a store, for example, via the Internet in China or your city.

Medical syringe needles are well suited for the same purposes. Their tips need to be sharpened to a right angle.

Molten Tin Removal Tool

There are several ways to remove liquid solder from the melt site:

shaking onto the floor, table or other surface;
sweeping with a brush or brush;
suction;
absorption into a special braid.

The first two methods are extreme; they are used in extreme cases. For normal high-quality work, the last two methods are suitable.

Liquid tin suction method

The tool adapted for it is called a tin pump. Appearance and the design of one of the many models is shown in the picture.

Before work, the spring is cocked. When the solder is melted to a liquid state, the tip of the device is applied to it and by pressing a button, the force of the released spring is forced to move the piston to provide a vacuum, which draws the liquid metal into a special cavity.

It is made by weaving from soft copper wire. Working with it is quite simple: a piece of braid is placed on the molten solder, and it quickly absorbs liquid tin.

Dismantling braid is sold in construction stores. An alternative can be a shielding core from an old coaxial cable for televisions, produced back in Soviet times. It is impregnated with a flux of alcohol and rosin.

How to safely unsolder a transistor, microcircuit, diode

Soldering conditions

Creating workplace should be addressed special attention for its lighting. You cannot solder a radio component in semi-darkness. If your vision does not allow you to clearly see all the details, then you need to wear corrective glasses.

The electronic board must be clearly fixed in space, and the body must be in a stable position. It is best to work sitting or standing on both legs, holding the soldering iron confidently. After all, any wrong move will cause irreparable harm.

Technology for dismantling radio components

The tip of the soldering iron should be precisely placed on the layer of solder located in the socket of one leg of the transistor and quickly melt it.

Then this place is injected with reverse side needle and separate the tin from the stem. If there is a dismantling braid or desoldering pump, then use them.

When the design of a radio component allows the use of a metal clamp to remove heat from the housing, then it must be used.

If the space for installing the soldering iron tip is very limited, then they work without using a heat remover.

In this case, special attention is paid to the length of time the radio component remains at elevated temperatures.

Features of dismantling microcircuits

The arrangement of the legs of the microcircuit strictly in a row allows you to melt the solder in all the sleeves of the contact pads of the board on one side of the case. This is a rather risky method, but in most cases with good skills it ends in success.

It is used when the tools described above for removing molten tin are not at hand, and the work needs to be done quickly.

Such operations are well provided by a transformer soldering iron with a tip made of copper wire, which can be bent to the shape of the legs of the microcircuit.

An awl or a thin screwdriver blade is placed under the microcircuit body. They act as a lever, move, and gradually pull out all the legs from their sockets at once at the moment the tin melts, but not before.

You should not try to completely remove the microcircuit in one go; it is enough to pull it out a little bit by bit on each side. At the same time, they monitor the temperature of the case and allow it to cool.

Using a similar method, I managed to remove the K554CA3 chip from the old board to work as its comparator.

In old boards, the legs of radio components were often bent on the reverse side and soldered. They are more difficult to dismantle. You will have to melt the tin on each leg, put a needle on the bend and use it to align the contact wire so that it comes out normally through the sleeve hole.

I suggest you watch the video by the owner of Radioblogful “How to desolder a microcircuit with three in different ways”

Hi all!. Today we will talk about in various ways dismantling microcircuits. It is with them that difficulties arise when soldering into parts various equipment.

“Why is it needed, you can buy it anyway, it costs a penny!” the average person will exclaim, not understanding and not attaching importance to the wealth hidden in old electronic equipment. I once wrote an article about how when there was nowhere to buy or nothing to buy.

Usually, there are no problems when soldering various small things. This is not a tricky thing, I heated it from the mounting side and pulled the leads out of the mounting holes one by one. The situation is much more complicated with microcircuits; there is more than one output; while one output has warmed up, the other has already cooled down. Moreover, bending the legs one at a time is not the case; that’s the only way they will fall off.

There are several methods for dismantling microcircuits:

Dismantling the microcircuit with a soldering iron

This is the most homeless and hemorrhagic trick when you have nothing but a soldering iron but need to desolder the microcircuit.

In order for this matter to go more or less smoothly, we clean the soldering iron from adhering solder. You can clean it with a special cellulose sponge or just with a damp cloth. Then, using a brush, coat all soldering joints with liquid flux, I use it for this. Now we first stick the cleaned soldering iron tip into the rosin and then poke it into the soldering points of the microcircuit pins. As a result, slowly, bit by bit, the solder begins to transfer from the mounting pad to the soldering iron tip. We, as it were, tin the soldering iron tip, but only take the solder from the terminals of the desired microcircuit.

This is what needs to be done large number iterations, not forgetting to clean the soldering iron tip each time until the microcircuit is released from the mounting captivity. It is very important here not to get carried away and not overheat the microcircuit. Also, mounting nickels and tracks can fly off due to overheating, but this is important in the sense that you don’t really need the microcircuit itself, but you do need the board itself.

Removing the chip using a razor blade

The main problem with desoldering microcircuits is, as I already said, that while you are heating one terminal, the other has already cooled down, and in order to remove the microcircuit, all terminals must remain heated at the same time. It’s difficult to do this with a soldering iron, but it’s possible. You can, of course, barbarically bend the tip of some EPSN soldering iron and use a kind of L-shaped hook to heat up the soldering. Or you can go simpler. Only in this case you need to use some kind of metal plate or bracket that is not tinned.

A razor blade can be used as such a plate. The blade is needed so that the heat from the soldering iron is concentrated not on one terminal, but is transferred to several at once. The only thing is that a more powerful soldering iron may be required, since at low power the heat that was enough for one pin may not be enough for a whole bunch of leads.

Therefore, we press the blade against a whole row of legs of the microcircuit and begin to warm up all the solders at the same time. We warm up and at the same time rock the microcircuit, you can slip a knife blade under the belly of the microcircuit, trying to lift the microcircuit from one edge. Thus, having freed one row of legs from the mounting captivity, in the same way, we free the second row.

Using dismantling braid

When dismantling microcircuits with a bare soldering iron, the ability of the soldering iron to attract solder is used. A soldering iron tip that is tinned and coated with flux has good wettability and absorbs solder very well. But how can we make this process more efficient?

You can, of course, choose a soldering iron with a wider tip, then it will be possible to remove a larger amount of solder. But you can go the other way, you can use the braid from a coaxial cable. The antenna wire from the TV will do. We tear off this braid from the cable and generously cover it with flux.

Now if you press such a pigtail to the solders of the microcircuit and walk a little over it with a soldering iron, you can verify the wonderful dismantling properties of the braid. Due to its porosity and hygroscopicity, it absorbs solder much better than any soldering iron tip, thereby freeing the microcircuit terminals.

Nowadays there are special dismantling braids on sale, so you can leave the TV wire alone.

Dismantling microcircuits using a desoldering pump

What do you think will happen if you combine an enema and soldering? You will get something shown in the figure. This is a tin pump and this construct was described in an old magazine, either “Modeler-Constructor” or “Radio Magazine”, I don’t remember.
Now they can look completely different, they can be like in the picture, they can be a modified syringe. But this does not change their essence: the soldering iron heats up the junction and the enema bulb or syringe draws out all the solder. In principle very effective method dismantling.

Using medical needles

In general, the point is as follows. At the pharmacy we buy a needle thin enough to fit into the mounting hole and thick enough to be placed on the terminal of the soldered microcircuit.

Using a file, we file the tip of the needle to make a simple hollow tube; it will be even better if the hole is flared a little. It turned out to be a good dismantling needle

And it’s very easy to work with her. We put our tube on the output of the microcircuit, and use a soldering iron to heat the junction. Now, while the solder is still in liquid form, we insert a needle into the mounting hole and begin to frantically rotate the needle until the solder hardens. By placing a needle on the pin, we thereby isolated the leg of the microcircuit from the solder.
The needle has a special coating that impairs the wettability of the solder, so the solder does not stick to the needle. or . Distinctive feature is that these alloys have a low melting point, less than 100 degrees.

To dismantle, pour a few granules into the joint. Now our task is to organize a puddle of alloy by distributing it over all the legs of the microcircuit. This allowed the low temperature alloy to mix with the solder alloy, resulting in a lower overall melting point. The thermal conductivity of the alloy is sufficient and a puddle of alloy covers all the legs of the microcircuit and melts everything. As a result, the chip is simply removed from the mounting holes.

Well, somehow that’s all I have for today.

I think that the article will be useful especially for beginners and will save several nerve cells when dismantling the next microcircuit.

Well, friends, don’t forget to subscribe to blog updates, and I wish you a sunny spring mood, good luck and success!

From n/a Vladimir Vasiliev

I had a lot of questions on the topic dismantling microcircuits in various buildings. I suggest you familiarize yourself with the most common options desoldering microcircuits in dip and smd cases.

First of all, we should talk about dismantling microcircuits a process that is the most accessible to radio amateurs, but also somewhat complex compared to the one that will be described a little later.

A method for dismantling microcircuits in a dip case using a soldering iron and several items that can be found around the house.

You need a soldering iron and a needle from a ten-cc syringe. We cut off the point of the needle so that it is smooth, without a point. We insert a needle with a hollow hole into the leg of the microcircuit from the bottom side, slowly heating it until the needle passes through the hole in the board. Without removing the needle, let the surface and solder cool, then remove the needle. We remove excess solder from the needle and repeat the process on the remaining pins of the microcircuit. With some skill, it turns out neatly and efficiently - the microcircuit itself falls out of the board without any external effort.

You will need a soldering iron and braid copper cable. We apply a layer of flux to the copper braid, place the leg of the microcircuit on one side and heat it up. When heated, the braid “pulls” solder onto itself from the surface of the board on which the microcircuit is located. When the braid is saturated, the unnecessary part is simply cut off and dismantling continues. It must be said that this method is suitable for both dismantling Dip components and Smd components.

To work, you still need the same soldering iron and something thin, such as tweezers or a flat-blade screwdriver. Carefully place the flat part of a screwdriver (or tweezers) between the microcircuit and fee to some reasonable depth, heat the legs on the reverse side, and slowly lift the side. We repeat the same process, but now on the other side of the part: insert a screwdriver, heat the legs, lift. And we repeat this process until the chip is removed from the board. The method is very fast, simple and even crude. But we must not forget that both the tracks on the board and the microcircuit itself have their own temperature limit. Otherwise, there is a possibility of being left without a working microcircuit, or with peeled tracks.

A soldering iron and a solder suction are required. A solder suction is something like a syringe, but with a piston that works on the principle of suction. We heat the output of the microcircuit, immediately apply a solder suction, press the button and the vacuum created inside the suction “pumps out” the solder from the track. Unfortunately, everything looks so easy and simple only in words. In fact, having heated the leg, you need to almost instantly hit the leg with suction and “pump out” the solder, which requires high speed performance, because the solder hardens almost instantly, and if you hold the soldering iron longer, there is a risk of getting peeled tracks or a burnt component.

Now we will talk about dismantling components using a soldering gun. The method is the simplest, most effective, fastest and highest quality. But, unfortunately, a soldering gun is not a cheap tool.

Method for dismantling the microcircuit indip - body.

You need a soldering gun and tweezers, preferably non-magnetic. Flux is applied from the side of the legs, and heating begins from the same side. The state of the tin on the terminals is visually monitored - when it has become sufficiently liquid, we carefully grab the part from the case side with tweezers and pull it out of the board.

Dismantling the microcircuit insmd version.

The principle is the same - flux is applied along the tracks, heated at a certain temperature, the degree of heating is determined by lightly nudging the part with tweezers. If the part becomes movable, slowly and carefully remove it from the surface of the board with tweezers, holding it by the edges and trying not to catch the tracks.

It is very important not to overheat the dismantled parts and surface! Each microcircuit and part has its own temperature limit, beyond which the part or board will be damaged. The hair dryer must be held STRICTLY vertically, selecting the desired nozzle, evenly heating the entire surface of the microcircuit. And don’t forget to set the air flow so as not to accidentally blow away neighboring components.

Well, that’s probably all the available methods for dismantling microcircuits. I hope you got the answer to the question: how to desolder a microcircuit.

We learn how to safely desolder radio components from boards. How to unsolder a microcircuit with a hairdryer

do-it-yourself desalter pump from a syringe, how to use, capacitors

Before you desolder a microcircuit from a board with a soldering iron, you should watch a training video. What do you do when an electrical appliance fails? Most likely, you take it to the master, a check is performed, after which he informs you that you need to resolder the parts in the circuit. After which, he does the work, you pay the money. Undoubtedly, to become a master in this field you need to study and gain a lot of knowledge. But if you approach this issue from the other side, then starting from the basics you can learn to do a lot on your own.

Desiccant pump: how to use it correctly

A vacuum desoldering pump is a very useful tool for soldering various radio components, be it microcircuits, a transistor, or, for example, a diode. Also, high-quality removal of tin from the contacts will help solder the working part without much difficulty.

The desoldering pump consists of:

Vacuum flask, spout made of thermal material;
Return spring;
Piston.

Soldering radio components with a desoldering pump is quite simple. First of all, it is necessary to “cock” the destin pump. To do this, you need to fix it with a locking mechanism by pressing the piston (the fixation occurs automatically). Next, heated to optimal temperature using a soldering iron, melt the tin on the contact of the part, having previously attached a destin pump to the contact.

After the tin has melted, remove the soldering iron, press the tin pump to the desoldering area and press it tightly. Press the locking mechanism button. The piston, moving back through the flask, creates a vacuum, due to which the tin is sucked in.

When soldering a large number of radio components, do not forget to periodically disassemble and clean the desoldering pump.

If you don’t have a desoldering pump at hand, and the part needs to be unsoldered, then you can make one from a regular syringe with your own hands. To do this, you need to take a syringe (50 cc if possible). We take out the piston and place a return spring in the syringe flask (the spring should be no longer than the flask so as not to squeeze out the piston). All that remains is to protect the nose. This can be done with any metal tube of the appropriate diameter. And the homemade desoldering pump is ready for use.

Braid for desoldering parts

Many professionals, as well as radio amateurs, know firsthand about the advantages of such an auxiliary “tool” as a desoldering braid. Its correct use in work allows you to quickly and efficiently get rid of tin on contacts, without damaging them.

You can braid:

Buy in store. There are a huge number of species;
Make it yourself from scrap materials.

Soldering parts using braiding occurs as follows. The soldering iron heats up to the desired temperature. A braid is applied to the desired contact and the contact is heated with a soldering iron. Then, using small circular movements, remove the tin from the contact.

Braid good quality, is always impregnated with rosin at the manufacturer's factory. When purchasing, check this important condition.

Buying braid will not be difficult. But due to its considerable cost and high consumption during operation, an excellent solution would be to make it yourself. To do this you will need a coaxial (radio frequency) cable or old stranded wires small section.

To make a cable braid, you will need a small piece of it. The top insulation is removed. Then the copper braiding of the cable is removed (take small pieces, this will ensure convenient removal of the braiding). The removed braid must be flattened and soaked in alcohol-rosin flux.

To make a braid of wires, you will need several small wires (suitable from headphones). The insulation is removed and several wires are twisted together. Next, they need to be flattened with a hammer. All that remains is to impregnate with flux.

How to desolder a microcircuit from a board with a hairdryer

The most in a fast way To unsolder a radio component, or to unsolder large circuits, this is the use of a hair dryer. It is worth considering that this method may disrupt operation or damage the part. Therefore, in the future, before soldering a part removed using a hair dryer, it is necessary to check its functionality with a multimeter.

To work you will need:

Flathead screwdriver.

We fix the board in a convenient position from which the required microcircuit will be soldered. A flat screwdriver is placed under it (used as a lever). On the reverse side of the board, a stream of hot air from a hair dryer heats up all the contacts of the microcircuit.

When heating the contacts with a hairdryer, try not to hold the air flow in one area. This reduces the likelihood of chip failure.

After the tin begins to melt, we begin to lift the microcircuit using a screwdriver. We carry out this work until the microcircuit is completely removed. After this (when replacing a part), the remaining tin is removed from the surface of the board, and the working microcircuit is soldered.

How to remove capacitors from a motherboard

Capacitors various types, perform an important function in the operation of any microcircuit. They pass or do not pass current, accumulate a certain charge, shift the phase and many more functions. And the failure of one of them affects the operation of the entire system. Therefore, timely replacement contributes to the uninterrupted operation of the circuit.

You don't need any special skills to remove capacitors from the motherboard.

To replace you will need:

Soldering iron;
Solder.

Not many people know that capacitors have one feature - thick contact legs. Soldering capacitors is not difficult. But the process of soldering them is somewhat more complicated due to this feature. This is determined by the fact that the legs are very difficult to warm up. In order to make the work easier and faster, use the proposed method.

This method will help to warm up the capacitor legs much better and avoid damage to nearby conductive tracks on the board.

A soldering iron or soldering station is heated to maximum temperature. A certain amount of solder is applied to the tip (to form a small drop). Next, using a heated drop of solder, we heat the legs of the capacitor to the desired temperature.

DIY desoldering pump (video)

Now, knowing several methods of soldering radio components and microcircuits, you can easily determine which one and in what case to use. And using some tricks will help you do the job competently and with understanding.

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6watt.ru

Soldering microcircuits from boards: desoldering parts with a soldering iron

Soldering microcircuits from the board is a non-trivial task, regardless of the type of controller. You unsolder one leg, but while you are working on the other, it freezes. You can bend the legs after unsoldering, but the problem of contacts breaking off again arises. The question arises, how to desolder a microcircuit from a board with a soldering iron? The answer is quite simple: use knowledge of physics and available objects. There are a number of options for carefully removing microchips from the board. But first, a little theory.

Microcircuits

Chip types

Currently, there are a number of cases, but only two are the most widespread, and in fact all other varieties are variants of two main types:

DIP - roughly speaking, this housing option for indoor installation, the legs of this controller fit into the holes on the board;
SMD – this type of microchip is designed for surface mounting; in this case, “spots” are placed on the board, to which the legs of the microcircuit are soldered.

Each option has its own advantages and disadvantages. But within the framework of the article, their features in terms of wiring are interesting. We’ll look at how to unsolder a microcircuit in a particular case a little lower.

Removing the DIP package

As already noted, this type of microcircuit is distinguished by its installation in holes on the circuit board. This imposes certain restrictions on the process of its dismantling. In order to carefully remove its legs from the holes, you need to remove the solder from the joint, almost completely freeing the legs. It should be noted that alternate heating and dismantling of a separate contact will not work here, since when it cools down, the remaining solder will again fix the microchip in place. Therefore, wiring the DIP package is optimal using the following methods:

Using improvised means - needles from medical syringes or special hollow tubes, now sold in electrical stores, are suitable for this purpose. But the option of using a medical needle is the cheapest and most accessible. To do this, you need to select a needle with a diameter slightly smaller than the mounting sockets for the microchip leg. Then cut off its pointed part with a file or simply bite it off, and then grind off the flattened part with a file. After this, installing the resulting hollow tube with an even cut on the mounting socket, simply heat it with a soldering iron, thereby freeing the chip leg;
The second option is to drag the solder from the soldering site onto copper wires moistened with flux, such as alcohol rosin. A wire with flux heated by a soldering iron gradually draws the solder onto itself from the soldering site. This option takes longer, but is also quite effective;
Using a soldering iron with solder suction - in this case, no particular difficulties in dismantling are expected. The main thing is to control the heating temperature in the contact area so as not to damage the board and the part itself.

These options will allow you to quickly and efficiently desolder DIP packages from the board.

Important! The main requirements for using a soldering iron in this case will be constant control over the pressure and temperature in the soldering zone. Overheating and excessive pressure can damage the part.

Solder pulling

Important! When using a medical syringe needle, you can simplify the task of cutting it; to do this, before cutting, it is enough to red-hot the cut area.

SMD controllers

Surface mounting of the housing makes it easier to dismantle. In this case, you can use a wide soldering iron tip and copper wire with flux and solder several contacts at once. But there are more interesting desoldering methods:

Using a strip of metal or half a razor blade to distribute the heat of a soldering iron over one row of IC legs. In this case, a steel strip is installed on a row of contacts on one side and heated with a tip until the solder melts, after which this side is slightly raised above the board. Then the solder on the other side of the chip is melted in the same way;
Using a long piece of copper braid with flux applied to it. The segment is placed on the legs of the microcircuit on one side and heated with a soldering iron; pulling the solder onto the braid, lift the part with tweezers. Then remove the solder from the other side of the controller in the same way;
Technically interesting option is the use of Rose or Wood alloys. Drops of this solder are applied to the contacts and heated, thereby reducing the melting point of the solder. Next, the solder gradually warms up, and the microcircuit is dismantled;
Using a hair dryer or blowtorch. To use this tool, flux is applied to the soldering areas. After that, the surface and the part are heated, and the microcircuit is removed from the mounting spots with tweezers.

It should be noted that each dismantling option is used in specific conditions; the main task in this case is to select the most optimal option from a safety point of view and, when using it, not to damage the part itself or the board traces.

Using a hair dryer

Important! When dismantling the microcircuit, it is important to remember that any parts or components on the board have their own temperature minimum; exceeding it will lead to the failure of the microcircuit.

The use of improvised means and a soldering iron when installing or dismantling microcontrollers is quite justified, but requires at least skills in working with a soldering iron. If they are absent, you should first practice on unnecessary parts. This process will allow you to gain the necessary experience on how to unsolder a microchip without damage, in addition, choose the most best option work with a specific board and type of chip package.

Video

elquanta.ru

How to remove radio components from a board - a review of techniques

What do you need for this?

Dismantling techniques

Interesting on the topic:

samelectrik.ru

How to remove a microcircuit from a board using a syringe needle

Soldering the IC with a needle

using suction;
soldering iron with nozzles;

Syringe needle

There are several advantages here:

the microcircuit does not overheat;
the paths do not deteriorate;
accessibility and simplicity;
cheapness.

Technology

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How to desolder a microcircuit from a board with a soldering iron - sovetskyfilm.ru

In the early 90s, when radio amateurs assembled home personal computers “Leningrad” and “Pentagon” on Z80 processors, the questions “how to solder chips correctly?” did not arise. All cases had a DIP form factor, the distance between the legs was sufficient to use an ordinary soldering iron with copper sting power 25 W.

Difficulties arose during the reverse process. In the absence of construction hair dryers, the question of how to unsolder the microcircuit was problematic. It was necessary to simultaneously heat 16, or even 54 legs, and quickly pull the part out of the board. However, real masters had their secrets.

The legs were freed from solder one by one, using thin tubes, for example, from a medical syringe.

There were even special soldering irons with suction of molten tin.

Today, the variety of cases and contacts on microcircuits does not allow us to do it the “old fashioned way”.

In industrial environments, installation printed circuit boards trusted to robots. In this case, the technology allows you to withstand the temperature without damaging the radio components. Namely, this question is most relevant when working with microcircuits.

If the soldering iron (or other heat source) is too powerful, you can burn the part (literally) the first time you touch it. On the contrary, a weak soldering iron will require prolonged exposure to the contacts, which will again lead to overheating. Low temperatures can lead to so-called “failures”, which are difficult to detect visually.

Which soldering iron to choose for working with microcircuits

Basically, there are three options:

Fixed Power Soldering Iron

An additional convenience of a 12-volt soldering iron is the ability to work autonomously in the garage when repairing car electronics.

The main component when working with microcircuits is the correct working tip. Of course, you can work with the classics - a copper rod with a flat sharpening at the end.

But such a tool is inconvenient when precise installation. Usually, to work with microcircuits, the tip is ground into a cone. In this case, the copper quickly wears out, and the tip has to be thrown away. In addition, this material oxidizes quickly and must be constantly cleaned.

Therefore, radio amateurs prefer ceramic soldering irons.

The power tool itself is no different from a regular one, except that the attachment of the tip is done differently. The main difference is the ceramic working tip. The material warms up instantly, is not subject to oxidation and practically does not wear out. The shape is immediately suitable for working with microcircuits - it has a cone sharpening.

Video presentation of a soldering iron with a ceramic tip that can be used to solder microcircuits.

Adjustable Power Soldering Iron

The main thing is not to confuse adjustable power with lowering the temperature during pauses between work. The device has a switch or button on the handle, with which you select the power and, accordingly, the temperature.

It is more convenient to work with such a device, since its range of application is much wider.

A variety of such soldering irons are instant heating guns. The peculiarity of the design is that when not in use the tip is cold. Just before soldering, you pull the trigger and the temperature instantly rises to operating temperature.

As a rule, such guns have several heating modes. In some way, it is possible to control the temperature by periodically applying voltage to the heating element manually by briefly pressing the trigger.

The disadvantage of the design is that it is somewhat bulky.

Soldering station. Ideal tool for soldering chips

They can be difficult to manage, or, on the contrary, primitive. The cost varies depending on the functions and the name of the manufacturer. Remains unchanged main principle work – full control over the power and temperature of the soldering iron. For boards with different types of parts, this is the best option.

By adjusting the power supply, you can instantly reconfigure the tool for working with planar microcircuits on the thinnest legs or for mounting rectifier assemblies with contacts with a cross-section of several millimeters.

There are also more advanced kits - stations with a set of soldering iron and a small heating hair dryer.

Moreover, there are temperature regulators on each of the components. Having such a set, you will not be tormented by the question of how to desolder the microcircuit from the board; for any form factor you can find a combination of hot air temperature and soldering iron tip.

The soldering station has two disadvantages: high cost and the need for certain operator qualifications. However, the advantages of the station over a conventional soldering iron outweigh these negative factors.

IMPORTANT! Before soldering microcircuits, it is necessary to ground the working tool.

It will be useful to put a special bracelet with a resistor on your hand (in case the working ground is damaged) and connect it to the ground. This will protect radio components from static voltage, which can damage them.

Review of a soldering iron that can solder microcircuits with a 900m tip.

Considering the precision and precision of work when soldering microelements, special attention should be paid to cleanliness working area. All contacts must be separated from each other by dielectric gaps, cleaned of oxides, and carefully tinned.

The soldering iron tip should not have traces of burnt flux, the amount of solder should be the minimum required for operation.

The mounting plate must be secured so that sudden movement does not damage nearby parts.

IMPORTANT! If you do not have experience in this kind of work, first practice on damaged radio components.

Detailed video lesson on how to learn how to solder correctly.

When some equipment breaks down, it is not at all necessary to immediately throw it in the trash. If you are interested in electronics and radio engineering, it would be wiser to solder the working elements of the microcircuit. Suddenly, in the future you will need a capacitor, transistor or resistor if you decide to make electronic homemade product. In this article we will tell you how to desolder radio components from the board so as not to damage anything.

What do you need for this?

There are many devices for soldering parts. Of course, a radio amateur cannot do without a soldering iron, which will be the main assistant in this matter. However, in addition to the soldering iron, in order to desolder the element, you will need:

You also need to prepare your workplace. It should be with good lighting. It is best if the lamp is located above the workplace so that the light falls vertically without creating shadows.

Dismantling techniques

So, first we will talk about the most popular technology - how to desolder a part from a board with a soldering iron without additional equipment. Then we will briefly consider simpler methods.

If you want to remove an electrolytic capacitor, just grab it with tweezers (or an alligator clip), heat the 2 terminals and quickly but carefully remove them from the board.

The situation is exactly the same with transistors. Apply solder to all 3 pins and remove the radio component from the board.

As for resistors, diodes and non-polar capacitors, very often their legs are bent during soldering from the back side of the board, which makes it difficult to solder without additional devices. In this case, it is recommended to first heat one terminal and, using a crocodile clip, with a little effort, pull part of the part out of the circuit (the leg should straighten). Then we perform a similar procedure with the second output.

We examined this technique when there is nothing at hand except a soldering iron. But if you purchased a set of needles, then it will be even easier to desolder the element: first heat the contact with a soldering iron, and then put the needle on the terminal suitable diameter(it should go through the hole in the chip) and wait until the solder cools down. After this, we take out the needle and get a bare lead that can be easily removed. If the radio component has several legs, we proceed in the same way - warm up the contact, put on the needles, wait and remove.

You can clearly see everything that we talked about in this article in the video, which provides the technology for desoldering elements from the board:

By the way, instead of special needles, you can even use ordinary ones that come with a syringe. However, in this case, you initially need to sharpen the end of the needle so that it is at a right angle.

Desoldering the part using a desoldering braid is also not difficult. Before starting work, wet the end of the winding with alcohol-rosin flux. After this, apply the braid at the desoldering site (on the solder) and heat it with a soldering iron tip. As a result, the heated solder should be absorbed into the braiding, which will free the terminals of the radio components.

With a desoldering pump, things are similar - the spring is charged, the contact is heated, after which the tip is brought to the molten solder and the button is pressed. A vacuum is created, which draws the solder into the desoldering pump.

That's all I wanted to tell you about how to desolder radio components from a board at home. We hope that the provided techniques and video lessons were useful and interesting for you. Finally, I would like to note that you can desolder the elements from the microcircuit with a hair dryer, but we do not recommend doing this. A hair dryer can damage nearby parts, as well as the parts you want to remove!

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Soldering the IC with a needle

Everyone solves this problem in their own way based on their experience and capabilities. But even having the opportunity to use a soldering station with a hair dryer, some still use this method. Me too. Therefore, in this article I decided to write how to desolder a microcircuit from a board using a needle from a syringe that I still use.

You can desolder the IC in several ways:

using suction;
soldering iron with nozzles;
soldering iron using tubes;
hair dryer (more suitable for desoldering large surface-mount ICs with planar leads).

Someone will say that this is the last century and it’s time to move on to more modern methods, but I like it because it allows you to desolder the microcircuit with a soldering iron, quickly and accurately. Whether this is right or wrong is up to you to decide for yourself. Of course, it is not suitable for all cases, for example, in order to desolder an SMD chip, you need a different technology.

Syringe needle

You don’t need to dream of any new devices or expensive soldering irons to solder radio components; this is the cheapest and most practical way that allows you to solder a microcircuit with a regular soldering iron at home using an ordinary needle from a syringe, which, if not lying around in the medicine cabinet, is easy available.

There are several advantages here:

the microcircuit does not overheat;
the paths do not deteriorate;
neighboring radio components do not heat up;
accessibility and simplicity;
cheapness.

Technology

Before starting work, you need to sharpen the needle a little at a right angle or leave a slight bevel, for convenience. Before heating the soldering with a soldering iron, put a needle on the protruding leg of the microcircuit and then just bring the soldering iron. Next, while heating the solder, slightly turn the needle; as the solder melts, the needle easily enters the hole in the board and releases the leg from the solder. Even with suction this is not always possible to achieve.

The microcircuit is carefully desoldered from the board and if you need to use it in the future, just go over the pins with a soldering iron to collect possible excess solder and the microcircuit is ready for use.

Now on the Internet you can find for sale a set of stainless steel tubes of various diameters, very popular sizes, made in China.

In this way you can solder only microcircuits, but also transistors, transformers (TDKS), variable resistors. The main thing here is to choose the size of the tube.

Hi all! The author of the blog popayaem.ru, Vladimir Vasiliev, is in touch with you. Today we will talk about various methods of dismantling microcircuits. It is with them that difficulties arise when soldering into parts of various equipment.

There are several methods for dismantling microcircuits:

Dismantling the microcircuit with a soldering iron

This is the most homeless and hemorrhagic trick when you have nothing but a soldering iron but need to desolder the microcircuit.

In order for this matter to go more or less smoothly, we clean the soldering iron from adhering solder. You can clean it with a special cellulose sponge or just with a damp cloth. Then, using a brush, coat all soldering joints with liquid flux; for this I use alcohol rosin. Now we first stick the cleaned soldering iron tip into the rosin and then poke it into the soldering points of the microcircuit pins. As a result, slowly, bit by bit, the solder begins to transfer from the mounting pad to the soldering iron tip. We, as it were, tin the soldering iron tip, but only take the solder from the terminals of the desired microcircuit.

So you need to do a large number of iterations, not forgetting to clean the soldering iron tip each time, until the microcircuit is released from the mounting captivity. It is very important here not to get carried away and not overheat the microcircuit. Also, mounting nickels and tracks can fly off due to overheating, but this is important in the sense that you don’t really need the microcircuit itself, but you do need the board itself.

Removing the chip using a razor blade

The main problem with desoldering microcircuits is, as I already said, this. that while you are heating one terminal, the other has already cooled down, and in order to remove the microcircuit, you need all the terminals to remain heated at the same time. It’s difficult to do this with a soldering iron, but it’s possible. You can, of course, barbarically bend the tip of some EPSN soldering iron and use a kind of L-shaped hook to heat up the soldering. Or you can go simpler. Only in this case you need to use some kind of metal plate or bracket that is not tinned.

Using dismantling braid

Nowadays there are special dismantling braids on sale, so you can leave the TV wire alone.

Dismantling microcircuits using a desoldering pump

Using medical needles

In general, the point is as follows. At the pharmacy we buy a needle thin enough to fit into the mounting hole and thick enough to be placed on the terminal of the soldered microcircuit.

Using a file, we file the tip of the needle to make a simple hollow tube; it will be even better if the hole is flared a little. It turned out to be a good dismantling needle

Now, by the way, there are special dismantling tubes of various diameters on sale, so honey. You don’t have to buy needles anymore.

Use of alloy rose

To dismantle microcircuits, you can use rose alloy or wood alloy. A distinctive feature is that these alloys have a low melting point, less than 100 degrees.

Well, somehow that’s all I have for today.

I think that the article will be useful especially for beginners and will save several nerve cells when dismantling the next microcircuit.

Well, friends, don’t forget to subscribe to blog updates, and I wish you a sunny spring mood, good luck and success!

From n/a Vladimir Vasiliev

Hello friends! I have had many questions on the topic of dismantling microcircuits in various cases. I suggest you familiarize yourself with the most common options for desoldering microcircuits in dip and smd cases. First of all, we should talk about dismantling microcircuits, a process that is the most accessible to radio amateurs, but also somewhat complex compared to the one that will be described a little later. The method of dismantling microcircuits in a dip case using a soldering iron and several items that can be found around the house. You need a soldering iron and a needle from a ten-cc syringe. We cut off the point of the needle so that it is smooth, without a point. We insert a needle with a hollow hole into the leg of the microcircuit from the bottom side, slowly heating it until the needle passes through the hole in the board. Without removing the needle, let the surface and solder cool, then remove the needle. We remove excess solder from the needle and repeat the process on the remaining pins of the microcircuit. With some skill, it turns out neatly and efficiently - the microcircuit itself falls out of the board without any effort from the outside. You will need a soldering iron and braided copper cable. We apply a layer of flux to the copper braid, place the leg of the microcircuit on one side and heat it up. When heated, the braid “pulls” solder onto itself from the surface of the board on which the microcircuit is located. When the braid is saturated, the unnecessary part is simply cut off and dismantling continues. I must say that this method is suitable for both dismantling Dip components and Smd components. To work, you need the same soldering iron and something thin, such as tweezers or a flat-tip screwdriver. Carefully insert the flat part of a screwdriver (or tweezers) between the microcircuit and the board to some reasonable depth, heat the legs on the reverse side, and slowly lift the side. We repeat the same process, but now on the other side of the part: insert a screwdriver, heat the legs, lift. And we repeat this process until the chip is removed from the board. The method is very fast, simple and even crude. But we must not forget that both the tracks on the board and the microcircuit itself have their own temperature limit. Otherwise, there is a possibility of being left without a working microcircuit, or with peeled tracks. A soldering iron and a solder suction unit are required. A solder suction is something like a syringe, but with a piston that works on the principle of suction. We heat the output of the microcircuit, immediately apply a solder suction, press the button and the vacuum created inside the suction “pumps out” the solder from the track. Unfortunately, everything looks so easy and simple only in words. In fact, after heating the leg, you need to almost instantly hit the leg with a suction and “pump out” the solder, which requires a high speed of execution, because the solder hardens almost instantly, and if you hold the soldering iron longer, there is a risk of getting peeled tracks or a burnt component again .Now we will talk about dismantling components using a soldering gun. The method is the simplest, most effective, fastest and highest quality. But, unfortunately, a soldering gun is not a cheap tool. A method for dismantling a microcircuit in a dip-case. You need a soldering gun and tweezers, preferably non-magnetic. Flux is applied from the side of the legs, and heating begins from the same side. The state of the tin on the terminals is visually monitored - when it has become sufficiently liquid, we carefully grab the part from the case side with tweezers and pull it out of the board. Dismantling an SMD microcircuit. The principle is the same - flux is applied along the tracks, heated at a certain temperature, the degree of heating is determined by lightly nudging the part with tweezers. If the part has become movable, slowly and carefully remove it from the surface of the board with tweezers, holding it by the edges and trying not to catch the tracks. It is very important not to overheat the dismantled parts and the surface! Each microcircuit and part has its own temperature limit, beyond which the part or board will be damaged. The hair dryer must be held STRICTLY vertically, selecting the desired nozzle, evenly heating the entire surface of the microcircuit. And don’t forget to set the air flow so as not to accidentally blow away neighboring components. Well, that’s probably all the available methods for dismantling microcircuits. I hope you received the answer to the question: how to desolder a microcircuit. If this article was useful to you, please share it on social networks by clicking on the buttons below. You also have the opportunity to subscribe to updates that constantly appear on the site. Good luck to you! All your questions and wishes can be stated in the comments. Attention, TODAY only!

Designation on the junction box diagram

Current transformer connection diagram

Photoresistor designation on the diagram

Microwave circuits

Chip types

Currently, there are a number of cases, but only two are the most widespread, and in fact all other varieties are variants of two main types:

DIP - roughly speaking, this version of the case is for internal mounting; the legs of this controller are placed in holes on the board;
SMD – this type of microchip is designed for surface mounting; in this case, “spots” are placed on the board, to which the legs of the microcircuit are soldered.

Removing the DIP package

As already noted, this type of microcircuit is distinguished by its installation in holes on the circuit board. This imposes certain restrictions on the process of its dismantling. In order to carefully remove its legs from the holes, you need to remove the solder from the joint, almost completely freeing the legs. It should be noted that alternate heating and dismantling of a separate contact will not work here, since when it cools down, the remaining solder will again fix the microchip in place. Therefore the wiringDIPcase is optimal using the following methods:

Using improvised means - needles from medical syringes or special hollow tubes, now sold in electrical stores, are suitable for this purpose. But the option of using a medical needle is the cheapest and most accessible. To do this, you need to select a needle with a diameter slightly smaller than the mounting sockets for the microchip leg. Then cut off its pointed part with a file or simply bite it off, and then grind off the flattened part with a file. After this, installing the resulting hollow tube with an even cut on the mounting socket, simply heat it with a soldering iron, thereby freeing the chip leg;
The second option is to drag the solder from the soldering site onto copper wires moistened with flux, such as alcohol rosin. A wire with flux heated by a soldering iron gradually draws the solder onto itself from the soldering site. This option takes longer, but is also quite effective;
Using a soldering iron with solder suction - in this case, no particular difficulties in dismantling are expected. The main thing is to control the heating temperature in the contact area so as not to damage the board and the part itself.

These options will allow you to quickly and efficiently desolder DIP packages from the board.

Important! The main requirements for using a soldering iron in this case will be constant control over the pressure and temperature in the soldering zone. Overheating and excessive pressure can damage the part.

Important! When using a medical syringe needle, you can simplify the task of cutting it; to do this, before cutting, it is enough to red-hot the cut area.

SMD controllers

Surface mounting of the housing makes it easier to dismantle. In this case, you can use a wide soldering iron tip and copper wire with flux and solder several contacts at once. But there are more interesting desoldering methods:

Using a strip of metal or half a razor blade to distribute the heat of a soldering iron over one row of IC legs. In this case, a steel strip is installed on a row of contacts on one side and heated with a tip until the solder melts, after which this side is slightly raised above the board. Then the solder on the other side of the chip is melted in the same way;
Using a long piece of copper braid with flux applied to it. The segment is placed on the legs of the microcircuit on one side and heated with a soldering iron; pulling the solder onto the braid, lift the part with tweezers. Then remove the solder from the other side of the controller in the same way;
A technically interesting option is to use Rose or Wood alloys. Drops of this solder are applied to the contacts and heated, thereby reducing the melting point of the solder. Next, the solder gradually warms up, and the microcircuit is dismantled;
Using a hair dryer or blowtorch. To use this tool, flux is applied to the soldering areas. After that, the surface and the part are heated, and the microcircuit is removed from the mounting spots with tweezers.

Important! When dismantling the microcircuit, it is important to remember that any parts or components on the board have their own temperature minimum; exceeding it will lead to the failure of the microcircuit.

The use of improvised means and a soldering iron when installing or dismantling microcontrollers is quite justified, but requires at least skills in working with a soldering iron. If they are absent, you should first practice on unnecessary parts. This process will allow you to gain the necessary experience on how to unsolder a microchip without damage, and also choose the most optimal option for working with a specific board and type of chip case.