Hello!
And here is the second part about the tool that you need to repair electronics.
To solder or not to solder, that is the question
In the previous article (Notes of the master. Tool. Part 1) we examined the tool required for repair without soldering. Many, for whom repair is just a hobby, are limited to modular repair and do not bother with soldering, since, unlike modular repair, soldering is not as easy as turning screws, and at the same time it is not always expedient from an economic point of view – it is rather difficult to explain to a person, why re-soldering some element on the board can cost as much as changing the display on his phone. At the same time, having plunged into this sphere with his head, he noted one sad trend for himself – a simplification of the approach to repair, a drop in the qualifications of an average craftsman and a slide from component repair to modular. The foremen of large service centers can also be understood, they usually have rather tough plans for the number of repaired devices, if they fail to fulfill them, they risk not receiving a bonus, or getting a much lower salary. And also, there is the problem of an oversupply of devices for repairs. The workshops are overflowing with faulty devices that need to be repaired. Because of this, it becomes much more profitable for the master to spend 15 minutes and change the entire module on which the faulty element is located, instead of losing 30-40 minutes, replacing this faulty element.
Figure: 1. Image taken from https://hsto.org/
An important role in the occurrence of such a situation was played by the availability of easy access to a large number of spare parts from the “heavenly”.
On the one hand, this is not bad, because if there is a module that can be replaced quite easily, you don't have to bother with soldering. On the other hand, the problem may be the lack of the required module, as well as the lack of a wizard who can find a donor microcircuit and replace it.
Therefore, I believe that having at least basic skills in working with a soldering iron is very useful.
But first, let's try to figure out what tools and materials we may need for this.
Tools and materials
Let's start with the basics – a soldering iron.
Soldering irons come in different capacities. It depends on the power of the soldering iron to what temperature it can heat up. For beginners, I recommend a 25 watt soldering iron. Working with such a soldering iron, you will minimize the risk of overheating the microcircuit, which means burning it.
In addition to power, the material and thickness of the tip may differ from the soldering iron.
The tip of the vast majority of soldering irons is replaceable. The finer the part that you have to solder, the thinner the tip should be. For a start, I recommend not to get carried away with jewelry work on miniature details, and start with large details to get your hand filled. Besides the size, the tip can be made of different materials. Classic copper tip (used for a very long time) and tip and nickel plated (more suitable for temperature-controlled soldering irons and soldering stations).
There are types of soldering work that simply cannot be done with a soldering iron. And here the so-called soldering hair dryer comes to the rescue.
According to the principle of operation, it practically does not differ from an ordinary household hair dryer. The only difference is the temperature and the intensity of the air flow that it can provide. It is used for a wide variety of types of work, ranging from directly, soldering microcircuits and ending with heating various surfaces before or after gluing. Such a hairdryer will cost significantly more than a soldering iron, therefore, if you nevertheless decide to become a master of soldering, then my advice to you is to buy a soldering station immediately equipped with both a soldering iron and a hairdryer.
Soldering stations are of different power and functionality, and therefore cost. The cost of such devices varies quite widely. A simple soldering station without a hair dryer can be bought for 1500-1800 rubles. There are copies for 15,000-20,000 rubles.
Among other things, there are infrared soldering stations, which I see no reason to talk about as part of home repairs as a hobby, because the cost of such equipment often exceeds 50 thousand rubles.
The undoubted convenience of the soldering station is the ability to adjust the temperature of the hair dryer and soldering iron within a fairly wide range.
Consumables
The materials you need for soldering come in a wide variety.
First, you need some solder.
In most cases, lead-tin alloys are used as solder. For example, the most common type of solder is POS-61, which means P – solder, O – tin, C – lead, 61 -% tin content.
Solder can also be different. The main difference is the melting point.
In electrical engineering, parts that are sensitive to overheating are often used, for which the use of solders with a melting point that excludes damage to the element is justified. The most commonly used solder in such cases is Rose. Its melting point is only 94 ° C.
Secondly, the flux.
According to Wikipedia, a flux is a substance (usually a mixture) of organic and inorganic origin, designed to remove oxides from the surface for soldering, reduce surface tension, improve the spreading of liquid solder and / or protect from the environment. Or, to put it more simply, a tool designed to make the solder stick better to the part.
The most famous flux is rosin. Rosin has many disadvantages, among which one of the main ones is aggressiveness towards metal elements and the ability to accumulate moisture, which means the risk of provoking a short circuit if you do not clean the part after soldering.
There are many types of fluxes. Fluxes from different materials, fluxes for different types of metals, fluxes for different soldering temperatures.
Thirdly, a flux-off cleaner. A tool with which you can clean the board after soldering with some types of fluxes.
Most often supplied in aerosol form. It costs about 300-400 rubles.
Conductive adhesive
The essence of this substance is reflected in its name. With this compound, conductive elements can be glued without soldering. The most common application is the gluing of thin stubs, which would be very difficult or impossible to solder due to the peculiarities of the location. But, in my practice, this material came in handy to me only once, when I restored the display cable on the Nexus 5, which had come unstuck from the junction with the matrix.
I think the topic of solders, fluxes, related materials and methods of their use is worthy of a separate article, so I propose to analyze this issue in detail in the next, third part of the article, which will be devoted to materials for soldering and methods and methods of their use. In other words, we will learn to solder.
More tools and equipment
Another very useful and very important device (which was mentioned several times in the comments to the previous article) is a regulated constant current source, most often referred to by the craftsmen simply as a 'power supply'.
This device is needed for a variety of tasks. This is also the direct recharging of severely dead batteries, when the standard charger is not able to 'push' the battery so that it comes out of the deep discharge state. And just the ability to run the device without a battery, for verification, or test.
The main parameter is the range of voltage and current that the device can give out, as well as the number of channels. The approximate cost of a single-channel unit with a current strength of up to 2 A and a voltage of up to 15 V is approximately 1200-1600 rubles. The cost of more advanced devices can go up to 20-30 thousand rubles. However, for home use, the simplest option is also suitable.
Multimeter
Wikipedia: Multimeter (from the English multimeter), tester (from the English test – test), avometer (from the ampere-voltmeter) – a combined electrical measuring device that combines several functions.
The minimum set includes the functions of a voltmeter, ammeter and ohmmeter. Sometimes a multimeter is performed in the form of a clamp meter. There are digital and analog multimeters.
In other words, this is the very device that will allow you to find a fault in the electrical circuit. Using a multimeter, you can find both an open circuit and a short circuit, which means, knowing the circuit of the device, identify the culprit in order to replace it.
Multimeters are of different accuracy, which depends on the capacity of the device. For example, the most common 3.5-digit portable voltmeters will have an accuracy of about 1%.
The cost of an inexpensive portable multimeter averages 350-450 rubles.
Third hand
In fact, this is a mount that allows you to fix the device being repaired in the desired position for the convenience of repair. Most often presented in the form of small clips on a stand with or without a magnifying glass. It can be equipped or not equipped with its own backlight. A very useful tool.
Binocular (microscope)
One of the most expensive devices in my arsenal.
An irreplaceable assistant in the case when work is required on very small details – soldering loops, small connections, etc. In fact, I do most of my soldering work under a microscope. This greatly facilitates the soldering process and quality control of the connection.
Hood
If it is possible to equip your workplace with a hood, then I strongly advise you to do so. The easiest way is to buy a corrugated pipe, fix one end of it over the place where the soldering work is being carried out, and bring the other end into the ventilation. Install a cooler of suitable dimensions inside. This will save your lungs and eyes from smoke and fumes, which, with all the desire, cannot be called useful.
Work laptop or stationary computer
I recommend using a separate computer as a working one, for firmware and software repair of devices. Separate, because frequent downloading and installation of special software and firmware, often from unknown resources, does not benefit the computer, since sooner or later you will do something 'very urgent', lose your guard and find your virus. ? So, infecting a separate computer is not as scary as the main one.
Conclusion
That, perhaps, is all that I wanted to tell about the tool that I need in my repair hobby. Of course, this is not all that a master may need, but we should not forget. that we are talking about home repair, as a hobby, and not a source of income. You can, of course, dream of an infrared soldering station, a stationary multimeter with an oscilloscope, and much more. But would such a purchase be justified? Definitely yes, you can only answer if you are going to make repairs your main source of income. In other cases, this is an unnecessary waste. As practice and personal experience show, you begin to acquire various tools gradually and slowly, when an opportunity arises, multiplied by an urgent need, and not just the desire to have this equipment. Therefore, my advice to novice craftsmen is not to rush to buy pieces of iron. Try it and you will understand what you need here and now, and what you can do without at first.
In the next article, we will talk in detail about the materials and alloys used in soldering (where, what, and why can be used), and also consider several techniques of this very soldering with practical examples.
By tradition, I will be glad to any criticism and advice in the comments.