Repairing laptops and video cards, reballing (dismantling and installing a chip with the restoration of solder balls) usually cannot be done without an infrared soldering station. Service centers They either don’t undertake such work or charge quite a lot of money for such repairs. Meanwhile, such breakdowns are quite common.
A factory-made IR station is a rather expensive device, so it’s more economical to make it yourself. An infrared soldering station can be made in one, maximum two days, by pre-ordering via the Internet and receiving the components for it by mail.
A little theory
At normal temperature The peak of electromagnetic radiation occurs in the infrared region. Things that burn emit both more intense and more energetic (shorter) infrared radiation. When it gets very hot, they start to glow red. The hotter they become, the more orange and yellow flowers, then blue.
Many organic molecules absorb infrared radiation intensely, which causes the object to heat up. Heat is the kinetic energy of the translational motion of atoms and molecules. The light emitted by an atom has a wavelength. As a result, the heated body also emits light, and the more heated the body is, the shorter the wavelength of the emitted light.
For information. According to Wien's displacement law, it happens that the thermal radiation of objects near room temperature is in the infrared region. This includes light bulbs and even people.
So, infrared radiation is not heat, and it does not (directly) cause heat. It is emitted by the heat of an object at a certain temperature range.
Visual shades of light are determined by the wavelength and its direction, starting with infrared, then red, orange, yellow…. violet and ending with the wavelength of ultraviolet radiation. And back too. Irradiation of a body with light causes an increase in the movement of its molecules, any light, but infrared, as the longest wavelength, is most effective.
A DIY IR soldering station is an infrared heater that emits heat to environment through infrared radiation.
DIY infrared soldering station
Bottom heating
The heating body can be made from an old Soviet suitcase made of aluminum, or from system unit computer. But the suitcase will fit better, because its working position is horizontal. As a last resort, you can look for a similar building at the nearest flea market.
It is necessary to cut a hole in the housing with a grinder for ceramic heaters. From an aluminum cutout, make a support for heaters with legs from ordinary bolts and nuts. The entire structure will be supported on the substrate.
The bottom heating consists of four ceramic heaters purchased on AliExpress. The price for them is reasonable, the seller provides fast delivery.
Each heater (dimensions: length - 24 cm, width - 6 cm) has a power of 600 W. Four heaters make up a 24x24 cm2 heating panel. This is enough to heat up a computer motherboard, not to mention a laptop motherboard, which is even smaller. Even large top-end video cards can be placed on such heating. For comparison, a standard factory Chinese station has such a heating area of 150x150 cm2, and it is not cheap.
From the bottom of the lower heating, each heater is connected to a terminal block, preferably of Soviet production. The block is made of a special material that does not melt at high temperatures. Connection of heaters in series-parallel:
- the first and third are connected in series;
- the second and fourth - also sequentially;
- the first and third with the second and fourth - in parallel.
This scheme is used to lighten the wiring a little. If you connect all heaters in parallel, the final load will be 2850 W:
- bottom heating – 600x4=2400 W;
- upper heater at maximum load – 450 W.
If there are also electrical equipment working in the room (several light bulbs, a computer, a soldering iron, a kettle), then the 16-amp circuit breaker will trip.
The series resistance of the load is calculated using a special formula. As a result, the bottom heating represents a load of 1210 W. It is easy to calculate that the entire IR station will consume 1660 W. This is not much for such equipment. In time, the board is heated by the bottom heating to 100 0 for about 10 minutes.
On top, when work is being done, you can put a metal grill from the refrigerator on the body with the heater. But it is better to use glass ceramics that match the size of the case, and make a convenient thermal table for board repair.
Top heating
The upper heating can be made from a Soviet photographic enlarger UPA-60. The model is suitable for a homemade soldering station. A ceramic heater measuring 80x8 cm fits perfectly onto a photo enlarger. In this case, you can adjust the height of the heater and the motor in any direction. It is convenient to attach the tripod to the table itself, and move the lower heating if necessary. The heaters are large enough to heat large chips and sockets for processor sockets.
All used parts can be bought on the Internet through the bulletin board, ceramic heater - on AliExpress.
Control block
A ready-made plastic box can be purchased at a special store for self-made electronics, or make a case from ordinary computer unit nutrition. The control panel contains:
- switches for lower and upper heating;
- dimmer 2 kW.
It should be noted that there are quite a lot of internal wires in the case, so you need to choose a rather large box.
The holes for bringing out the controls to the front panel are cut with a jigsaw with a special metal file. Usually this does not cause difficulties if you have practice with a similar instrument.
PID controller REX-C100 can also be ordered on AliExpress. Included with it, the seller supplies a solid-state relay and a thermocouple. That is, the controller reads what temperature the ceramic heater reaches. Until the temperature reaches the desired value, the solid-state relay is in the open state and passes electricity to a ceramic heater.
When the device reaches the required temperature, the solid-state relay is activated and turns off the current supply to the ceramic heater. The dimmer is controlled manually. Usually it is set to maximum so that the top heats up faster.
Tester
This device is needed to work in order to read information about the temperature near the chip. A regular thermocouple is connected to it, the end of which is placed near the chip. The tester display will show the temperature directly near the chip.
Important! The wire from the thermocouple is wrapped with heat-resistant tape, because the wire braid burns at high temperatures.
As a result, a hastily assembled homemade IR soldering station will cost about ten times less than a finished product. The device can be modified and gradually improved.
Work in practice
The operation of the device will be described using the example of repairing a laptop board. One of the board's malfunctions is the breakdown of the video chip. Sometimes it is enough to warm it up with a hot air gun, and the image appears on the screen. Most likely, in this case, the crystal falls off the PCB. Changing the chip is quite expensive. But if you warm it up, you can extend the life of the laptop. Using the example of such banal heating, a homemade infrared soldering station can be used.
To begin with, prepare the board for heating, remove the parts:
- films, because they begin to melt at high temperatures;
- CPU;
- memory.
It is better to remove the compound with tweezers after preheating it with a hot air gun. The hairdryer is set at a temperature of 1800, medium air flow.
Important! The entire surrounding area around the chip must be covered with foil so as not to heat the board elements. Just in case, you should also close the plastic memory connectors.
For information. The use of fluxes facilitates the soldering process and prevents oxidation of the metal of the soldered elements.
The board in this form is installed on the lower heating grid of the soldering station. A thermocouple is placed near the chip. Another thermocouple is located close to the heaters, its task is to read the temperature of their heating. Turn on the bottom heating on the control unit. On the tester and PID controller operating parameters appear.
When the bottom warms up, you need to wait until the temperature around the chip is at least 1000, depending on the solder material. If the solder is lead-free, then it is advisable to heat it to 1100.
The distance between the chip and the upper heater should be about 5 cm. The center of the chip should be strictly under the center of the upper heater, because the maximum temperature goes from the center to the sides. The top heater is turned on when the temperature near the chip rises to 1100. The bottom usually warms up for 10 minutes, then the top is turned on, which should heat up to 2300. On the PID controller, the top value shows the current temperature, the bottom - the temperature that needs to be reached.
When the desired temperature is reached, the upper heater is turned on, which is controlled by a dimmer. When the temperature comes closer to 2300, the power of the dimmer needs to be reduced. This is done to prevent heating too quickly. It is recommended to maintain a minute at a temperature of 2300 and then turn off the device. The temperature will drop.
Bottom heating, also known as an infrared heater, is used for uniform heating during dismantling and installation of BGA components and microcircuits.
Why do you need bottom heating?
In the picture below we see a BGA chip that is located on a printed circuit board. If you blow hot air onto a microcircuit, then the microcircuit will only warm up from above. The solder balls and PCB will be cooler than the chip itself. As a result, the microcircuit may overheat and fail.
The situation changes dramatically for the better if you heat the board with the microcircuit not only from above, but also from below using bottom heating.
In this case, both the board and the microcircuit will warm up from all sides: both below and above. The solder balls and PCB will already be hot, as will the chip. As a result of this, the solder balls on both the bottom and top will melt at the same time, which reduces the risk of tearing off the printed conductors on the PCB itself.
There is also a second advantage of bottom heating. When we heat it with a hairdryer without bottom heating, the board gets very hot in some places, but not in others. Due to the expansion of the substance under the influence of temperature, in places where we fry with a hairdryer, the board will expand and can lead to dire consequences. It will swell and break the connections between the layers, since the boards mobile phones and computers are made multi-layered. With the help of bottom heating, the board is heated evenly over the entire area, therefore, sad consequences can be avoided.
How to work with bottom heating
My bottom heater looks like this
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Here we have four clamping bolts with which our patient is clamped
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Basically, I set the temperature on my bottom heating platform to 200 degrees. To do this I press the button
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and turn the wheel
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We fix the patient and wait five minutes. When our board warms up, we begin dismantling the SMD component.
Where to buy bottom heating
On Ali, where else)
You can look them up at this link.
But it’s better to take a closer look at soldering platforms that combine not only bottom heating, but also a soldering iron and a hair dryer in one set. Such a soldering platform will be even more convenient than buying everything separately
Sooner or later, a radio mechanic involved in the repair of modern electronic equipment is faced with the question of purchasing an infrared soldering station. The need has arisen due to the fact that modern elements in short, producers of both small and large integrated circuits they abandon flexible terminals in favor of snouts. This process has been going on for quite some time.
Such chip packages are called BGA - Ball grid array, in other words - an array of balls. Such microcircuits are mounted and dismantled using a non-contact soldering method.
Previously, for not very large microcircuits it was possible to get by with a hot-air soldering station. But large GPU graphics controllers cannot be removed and installed with a thermal air blower. Maybe just warm it up, but warming it up doesn’t give long-term results.
In general, closer to the topic.. Ready-made professional infrared stations have exorbitant prices, and inexpensive 1000 - 2000 green ones do not have enough functionality, in short, you still have to add them. Personally, for me, an infrared soldering station is a tool that you can assemble yourself and to suit your needs. Yes, I don’t argue, there are time costs. But if you approach the assembly of the IR station methodically, you will get the desired result and creative satisfaction. So, I have planned for myself that I will work with boards measuring 250x250 mm. For soldering TV Main and computer video adapters, possibly tablet PCs.
So, I started with a blank slate and a door from an old mezzanine, screwing 4 legs from an ancient typewriter to this future base.
Using approximate calculations, the base turned out to be 400x390 mm. Next, it was necessary to roughly calculate the layout based on the sizes of the heaters and PID controllers. Using this simple “felt-tip pen” method, I determined the height of my future infrared soldering station and the bevel angle of the front panel:
Next, let's take on the skeleton. Everything is simple here - we bend the aluminum corners according to the design of our future soldering station, secure it, and tie it together. We go to the garage and bury our heads in DVD and VCR cases. I do a good job of not throwing it away - I know it will come in handy. Look, I’ll build a house out of them :) Look, they build from beer cans, from corks, and even from ice cream sticks!
In short, you can’t imagine a better cladding than equipment covers. Sheet metal is not cheap.
We run to the shops in search of a non-stick baking sheet. The baking tray must be selected according to the size of the IR emitters and their number. I went shopping with a small tape measure and measured the sides of the bottom and the depth. To questions from sellers like - “Why do you need pies strictly given dimensions? He answered that the inappropriate size of the pie violates the overall harmony of perception, which does not correspond to my moral and ethical principles.
Hurray! The first parcel, and it contains especially important spare parts: PIDs (what a scary word) The decoding is also not simple: Proportional-Integral-Differential controller. In general, let’s understand their setup and operation.
Next is the tin. This is where we had to work hard with the DVD covers so that everything would turn out smoothly and solidly, we’re doing it for ourselves. After adjusting all the walls, you need to cut the necessary holes for the FIDs on the front wall, for the cooler on the back wall and for painting - in the garage. Eventually - intermediate option Our IR soldering station began to look like this:
After testing the REX C-100 regulator designed for preheating (bottom heater), it turned out that it is not entirely suitable for my soldering station design, because it is not designed to work with solid-state relays, which it is supposed to control. I had to modify it to fit my concept.
Hurray! A parcel has arrived from China. Now it already contained the most basic wealth for building our infrared soldering station. Namely, these are 3 lower IR emitters 60x240 mm, the top 80x80 mm. and a pair of 40A solid-state relays. It was possible to take 25 amps, but I always try to do everything with a reserve, and the price was not much different..
The eyes are afraid, but the hands are doing. I try not to forget this old truth, just like about chicken, one grain at a time... What we have in the end - After installing the emitters in a baking tray, installing the solids on the radiator, blown by the cooler and connecting everything, we got something more or less similar to infrared soldering station.
Once the preheating thing started to come to an end and the first tests on heating, temperature retention and hysteresis were done, we could safely move on to the upper infrared emitter. It turned out to be more work than I initially expected. Several design solutions were considered, but in practice the last option turned out to be more successful, which I implemented.
Making a table to hold the board is another task that requires heating the skull. It is necessary that several conditions be met - uniform holding of the printed circuit board so that the board does not sag when heated. In addition, it was possible to move an already clamped board left or right. The board clamp should be both strong and give a little slack, since the board expands when heated. Well, the table should also have the ability to secure the boards different sizes. Not yet fully finished table: (no clothespins for the board)
Now the time has come for testing, debugging, adjusting thermal profiles for different types of microcircuits and solder alloys. During the fall of 2014, a decent number of computer video cards and television Main-boards were restored
Despite the fact that the soldering station seems complete and has proven itself to be excellent, in fact, several more important things are missing: Firstly, a lamp, or a flashlight on a flexible leg, Secondly, blowing the board after soldering, Thirdly, I initially wanted to make a selector for the lower heaters..
Of course, I didn’t write everything I wanted, because during assembly there were a lot of little things, problems and dead ends. But I recorded the entire construction process on video and now this is a full-fledged training video course:
An infrared soldering station is a device for soldering microcircuits in a BGA package. If what you read doesn’t tell you anything, you probably shouldn’t go to the cat. There are arduinos, graphs, programming, ammeters, screws and blue electrical tape.
First background.
My professional activity related in some way to electronics. Therefore, relatives and friends constantly strive to bring me some electronic device that is not quite working properly with the words “well, look, maybe some wiring has come unsoldered.”
At that time, such a thing turned out to be a 17" eMachines G630 laptop. When you press the power button, the indicator came on, the fan made noise, but the display was lifeless, there was no sound signals and activity hard drive. An autopsy showed that the laptop was built on AMD platform, and the north bridge is marked 216-0752001. A quick Google showed that the chip has a very poor reputation for reliability, but problems with it are easily diagnosed. You just need to warm it up. I set the soldering gun to 400 degrees and blew on the chip for 20 seconds. The laptop started up and showed the picture.
The diagnosis has been made. It would seem that it’s a small matter - re-soldering the chip. This is where the first revelation awaited me. After calling service centers, it turned out that the minimum amount for which you can change a chip in Minsk is $80. $40 for the chip and $40 for the labor. For a laptop with a total cost of $150, it was not very budget-friendly. A friendly introduction service offered to resolder the chip at cost - for $20. The final price tag dropped to $60. The upper limit of a psychologically acceptable price. The chip was successfully soldered, the laptop was assembled, given away, and I happily forgot about it.
The second background.
A few months after the end of the first backstory, a relative called me and said, “You love all kinds of electronics. Pick up your laptop for spare parts. For free. Or I'll just throw it in the trash. They said it looked like a motherboard. Chip dump. It is not economically feasible to repair.” So I became the owner Lenovo laptop G555 without hard drive, but with everything else, including power supply. Turning it on showed the same symptoms as in the first prehistory: the cooler is spinning, the lights are on, there are no more signs of life. The autopsy showed an old friend 216-0752001 with traces of manipulation.
After warming up the chip, the laptop started up as if nothing had happened, as in the first case.
Reflections.
So I found myself the owner of a laptop with a faulty north bridge. Should I take it apart for parts or try to repair it? If the latter, then solder it on the side again, even for 60 dollars, and not 80? Or buy your own infrared soldering station? Or maybe assemble it yourself? Do I have enough strength and knowledge?
After some thought, it was decided to try to fix it, and to fix it myself. Even if the attempt is unsuccessful, it won’t hurt to disassemble it for parts. And the infrared station will be a useful aid in many works that require preheating.
Technical task.
Having studied the prices for ready-made industrial infrared stations (from $1000 to plus infinity), sifted through a bunch of topics on specialized forums and videos on Youtube, I finally formed the terms of reference:
1. I will make my own soldering station.
2. The design budget is no more than $80 (two solderings at the service center without materials).
Additionally, the following were purchased offline:
Linear halogen lamps R7S J254 1500W - 9 pcs.
Linear halogen lamps R7S J118 500W - 3 pcs.
R7S cartridges - 12 pcs.
The following were pulled out of the trash in the garage:
Docking station from some antediluvian Compaq laptop - 1 pc.
Tripod from a Soviet photo enlarger - 1 pc.
Power and signal wires, an Arduino Nano, and WAGO terminal blocks were found in a home storage room.
Bottom heater.
We arm ourselves with a grinder and cut off everything unnecessary from the docking station.
We attach cartridges to a sheet of metal.
We connect three cartridges in series, resulting in three chains in parallel. We install the lamps and hide them in the housing.
The search for material for the reflector took a long time. I didn't want to use foil because I suspected it wouldn't last long. It was not possible to use thicker sheet metal due to difficulties in processing it. A survey of familiar employees of industrial enterprises and a visit to non-ferrous metal purchase points did not yield any results.
In the end, I was able to find sheet aluminum that was slightly thicker than foil, which was ideal for me.
Now I know exactly where to look for such sheets - from printers. They attach them to the drums in their cars, either to transfer paint, or for something else. If anyone knows, tell me in the comments.
Bottom heater with installed reflector and grille. Instead of a grille, it is more correct to use, but it is not at all budget-friendly, like everything with the “Professional” sticker.
Shines a beautiful orange light. It doesn’t burn your eyes, you can look at the light completely calmly.
Consumes about 2.3 kW.
Upper heater
The design idea is the same. The cartridges are screwed with self-tapping screws to the cover of the computer power supply. A reflector bent from an aluminum sheet is attached to it. Three five hundred watt halogens are connected in series.
It also glows orange.
Consumes about 250 watts.
Control circuit
An infrared station is an automatic machine with two sensors (board thermocouple and chip thermocouple) and two actuators (lower heater relay and upper heater relay).
It was decided that all the heating power control logic would be implemented on a PC. Arduino will only be a bridge between the station and the PC. I received the parameters for PWM control of the heaters from the PC - set them - sent the temperature of the thermocouples to the PC, and so on in a circle.
Arduino expects messages like SETxxx*yyy* on the serial port, where xxx is the power of the upper heater in percent, yyy is the power of the lower heater in percent. If the received message matches the template, the PWM coefficients for the heaters are set and the OKaaabbbcccddd message is returned, where aaa and bbb are the installed power of the upper and lower heaters, ccc and ddd are the temperature received from the upper and lower thermocouples.
A “real” hardware PWM microcontroller with a sampling frequency of several kilohertz is not applicable in our case, since a solid-state relay cannot turn off at an arbitrary point in time, but only when the alternating voltage passes through 0. It was decided to implement our own PWM algorithm with a frequency of about 5 hertz. At the same time, the lamps do not have time to go out completely, although they flicker noticeably. In this case, the minimum duty cycle, at which there is still a chance to capture one period of the mains voltage, turns out to be 10%, which is quite enough.
When writing the sketch, the task was to refuse to set delays using the delay() function, since there is a suspicion that at the moment of delays, data from the serial port may be lost. The algorithm turned out to be as follows: in an endless loop, the presence of data from the serial port and the value of the software PWM time counters are checked. If there is data from the serial port, we process it; if the time counter has reached the PWM switching values, we carry out actions to turn the heaters on and off.
#include
Application for computer.
Written in Object Pascal in the Delphi environment. Displays the status of the heaters, draws a temperature graph and has a built-in primitive modeling language, more reminiscent of some kind of Verilog in philosophy than example Pascal. A “program” consists of a set of “condition-action” pairs. For example, “when the lower thermocouple reaches a temperature of 120 degrees, set the power of the lower heater to 10%, and the upper heater to 80%.” This set of conditions implements the required thermal profile - heating rate, holding temperature, etc.
The app has a timer that ticks once per second. Based on a timer tick, the function sends the current power settings to the controller, receives back the current temperature values, draws them in the parameters window and on the graph, calls the procedure for checking logical states, and then goes to sleep until the next tick.
Assembly and test run.
I assembled the control circuit on a breadboard. Not aesthetically pleasing, but cheap, fast and practical.
The device is finally assembled and ready to launch.
A run on the test board revealed the following observations:
1. The power of the bottom heater is incredible. The temperature graph of a thin laptop board shoots up like a candle. Even at 10% power, the board confidently heats up to the required 140-160 degrees.
2. The power of the upper heater is worse. It is possible to heat the chip even to a temperature of “low +50 degrees” only at 100% power. Either it will have to be redone later, or let it remain as a protection against the temptation to underheat the bottom.
Buying a chip on Aliexpress.
There are two types of bridges 216-0752001 on sale. Some are declared as new and cost from $20 each. Others are listed as "used" and cost $5-$10 each.
There are many opinions among repairmen regarding used chips. From categorically negative (“bugger, come to me, I have a pile of used bridges right under the table after resoldering, I’ll sell them to you inexpensively”) to cautiously neutral (“I plant them sometimes, they seem to work fine, returns, if there are any, are not much more often than new ones").
Since my repairs are ultra-budgetary, it was decided to install a used chip. And to be on the safe side in case of a trembling hand or a faulty copy, a lot “2 pieces for 14 dollars” was found.
Chip removal
We install the board on the bottom heating, attach one thermocouple to the chip, the second to the board away from the chip. To reduce heat loss, cover the board with foil, with the exception of the window for the chip. We place the upper heater above the chip. Since the chip has already been replanted, we load a self-invented profile for lead solder (heating the board to 150 degrees, heating the chip to 190 degrees).
Everything is ready to start.
After the board reached a temperature of 150 degrees, the upper heater automatically turned on. Below, under the board, you can see the heated filament of the lower halogen.
Around 190 degrees the chip “floated”. Since the vacuum tweezers did not fit into the budget, we hook it with a thin screwdriver and turn it over.
Temperature chart during dismantling:
The graph clearly shows the moment the upper heater is turned on, the quality of stabilization of the board temperature (yellow large wavy line) and the chip temperature (red small ripples). The red long “tooth” downwards means the thermocouple is falling from the chip after it is turned over.
Soldering a new chip
Due to the responsibility of the process, there was no time to take photographs or take screenshots. In principle, everything is the same: we go over the nickels with a soldering iron, apply flux, install the chip, install thermocouples, work out the soldering profile, and with a slight wobble we make sure that the chip has “floated.”
Chip after installation:
It can be seen that it sat more or less straight, the color has not changed, and the textolite is not bent. The prognosis for life is favorable.
With bated breath we turn on:
Yes! Motherboard started. I re-soldered the first BGA in my life. Moreover, it was successful the first time.
Approximate cost estimate:
Bulb J254: $1.5*9=$13.5
Bulb J118: $1.5*3=$4.5
Cartridge r7s: $1.0*12=$12.0
Thermocouple: $1.5*2=$3.0
MAX6675: $2.5*2=5.0
Relay: $4*2=$8.0
Chips: $7*2=$14.0
Total: $60 minus the remaining spare chip.
The laptop was assembled, and the one found in the table was added to it. HDD 40 GB, installed operating system. To prevent similar incidents in the future, using k10stat, the supply voltage of the processor core is reduced to 0.9V. Now, during the most severe use, the processor temperature does not rise above 55 degrees.
The laptop was installed in the dining room as a movie library for the youngest member of the family, who refuses to eat without his favorite cartoons.
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