Various malfunctions of welding inverters. Features of operation and possible malfunctions of welding inverters The overheating lamp is on during welding

Here we will consider the repair of the TELWIN Force 165 welding inverter. For those who are not familiar with the design and circuitry of the welding inverter, we suggest that you first familiarize yourself with the materials on this topic, namely:

In these two articles, using the example of a real TELWIN Force 165 device and a circuit diagram welding inverters TELWIN Tecnica 144-164 describes in detail the electronic filling and purpose of each circuit element.

But let's return to our faulty device - the TELWIN Force 165 welding inverter. According to the owner, the device was working properly, but suddenly, after a short break in work, it completely refused to perform its duties. When trying to start work, a spark did not appear, and an unnatural sound was heard from inside the case. regular work"hum" and "squeak".

According to the owner, it was also known that the device seemed to be working - the noise of the blower fan was heard, and the normal operation indicator turned on. This indicates that the inverter transistors are working properly.

One got the impression that the welding inverter “goes into protection” - the internal protective circuits that are part of any pulsed unit, especially such a powerful one, are triggered.

I started troubleshooting the welding inverter in an unconventional way. I did not turn on the device.

I had never encountered such devices before, and they were new to me. Therefore, the first thing I did was open the case and began to check all the details hitherto known to me with a multimeter.

On printed circuit board welding inverter found familiar elements: a fan, a powerful diode bridge (a radiator is installed on it), high-voltage electrolytic filter capacitors, an EMC filter, key powerful inverter transistors (installed on a radiator), a pulse transformer, an electromagnetic relay ...

An unpleasant surprise was that the surface of the printed circuit board was filled with some kind of varnish, which made it difficult to read the markings of SMD elements and microcircuits.

Security elements were also discovered. One of them is a 90 0 C thermal fuse. It is glued to the radiator of the diode bridge.

As far as I know, such thermal fuses operate permanently, that is, if they heat up above their operating temperature, they open forever. Similar thermal fuses can be found in power transformers. There they are included in the circuit of the primary winding and glued to it. Protect the transformer from overheating. Sometimes you can falsely judge that the primary winding of the transformer is broken, although as soon as you remove (or short-circuit) this same thermal fuse, it turns out that the transformer is working.

Therefore, the first thing I did was check the integrity of the thermal fuse at 90 0 C. It turned out to be working.

In addition, on one of the radiators, to which the powerful key transistors of the inverter are attached, there is also temperature sensor. Externally, it is very similar to the KSD series thermal switch, which are used in thermopots, water heaters and other household electrical equipment.

The peculiarity of these thermal switches is that their contacts close again if the temperature drops below a certain value. It is clear that this temperature sensor monitors the heating of powerful key transistors and, if there is overheating, temporarily turns off the operation of the welding inverter. As soon as the radiators, and, consequently, the transistors, cool down, the device will start up again and operate normally.

When checking the thermal switch, it turned out that it was also working. Well, let's look for the problem further.

After some searching, it was decided to test powerful rectifier diodes. On the printed circuit board they are arranged in a row and securely screwed to the radiator with screws. The pages of the site have already talked about how to check the diode.

Labeled as 60CPH03. These are ultra-fast dual diodes VS-60CPH03.

After checking, it turned out that all three dual diodes were approximately faulty. But this is just an assumption, since the diodes are soldered into the circuit, and it is impossible to say 100% that they are faulty. Despite this, it became clear in which direction we needed to “dig” further.

It would have been possible to understand the problem without the diagram, but with it it was more interesting, especially since I had at hand a repair manual for TELWIN Tecnica 144-164 welding inverters, which, frankly speaking, are not much different in their composition and circuitry from the TELWIN Force 165. If you look at schematic diagram, then you can notice that even if one of the dual 60CPH03 diodes breaks down, all other diodes during testing will also be “faulty” if they are not removed from the board and each one is not checked individually. Here is a piece of the circuit - the output rectifier.

As it turned out, desoldering these same diodes is not so easy. Firstly, the soldering is very decent and high quality. And how could it be different, because huge currents flow in the power part of the welding machine, up to 130 amperes! The slightest lack of solder and the contact point will heat up, and this will subsequently lead to a malfunction. Therefore, the Italians do not spare solder and reliably flavor the contact area with it.

Don't forget that modern electronics are made using lead-free solders, and their melting point is usually higher than that of conventional tin-lead.

Before soldering the diodes, it is necessary to dismantle the radiator. The screws that secure the diodes to the radiator are non-standard, but you can unscrew them with pliers.

For desoldering, it is better to use a more powerful soldering iron. It is better to take a regular soldering iron with a power of 50 watts, otherwise desoldering will turn into torture. You can, of course, use a 40-watt soldering iron, but this will require skill and a lot of patience. You need to have time to thoroughly warm up all 3 leads of the diode at the same time.

When dismantling, you can try using copper braid or a desolder to remove solder. True, if the soldering iron is low-power (for example, 40 watts), then they will be of little use. The solder will harden instantly.

Despite the difficulties caused by the low power of the soldering iron (I have a 40-watt soldering iron) and the burnt copper tip, I still managed to desolder the dual diodes. Unfortunately, not without its “jambs”.

I tore out by the roots the through metallization of the copper tracks. Oh, okay, no problem. Let's clean it up and build it up.

It turned out that one of the diodes was broken - the rest were intact. It is worth noting that both diodes, which are part of one dual diode, turned out to be broken. Now this is not a diode - but a “sieve” - an ordinary conductor in a beautiful case.

If you look at the diagram, the diode indicated by the red circle has “flyed out”.

Let me remind you that a piece of the circuit is taken from the manual for TELWIN Tecnica 144-164. And I was repairing TELWIN Force 165. Telvin Force 165 does not have an L1 inductor on the board (inductor) and, apparently, should not have it, since seat there is no one for it on the board. So don't pay any attention to her. In reality, this coil is made of copper wire large cross-section to withstand currents up to 140 amperes.

It was decided to leave the device alone and start looking for a replacement for the faulty VS-60CPH03 diode. Finding a replacement for the 60CPH03 diode was not so easy. It was not possible to buy this radio component on the Internet. For some reason, such a detail is rare in online stores (perhaps everything has already changed). I had to go to the radio market and buy there.

An analog diode with markings was purchased STTH6003CW. His price turned out to be decent, and finding the right one was not easy.

The parameters of the STTH6003CW are the same as those of the VS-60CPH03, namely:

Frame - TO-247;

Maximum current in direct connection I F(AV)– 30A for 1 element (60A for both diodes);

Allowable reverse voltage V RRM– 300V;

Recovery time (or speed) t rr (max)– 50 ns (50 nanoseconds).

The STTH6003CW dual diode belongs to the so-called high-speed diodes. The bourgeoisie call such diodes names Ultra-fast, Hyperfast, Super-fast, Stealth diode, High frequency secondary rectifier and so on. In general, as soon as they don’t try to emphasize their coolness.

The main feature of a high-speed diode is its ability to open quickly (pass current) and also close quickly (not pass current). This means that it can operate at high frequencies. This is what is required for operation in the rectifier of a welding inverter, since it is necessary to rectify high frequency current - tens of kilohertz.

Therefore, such diodes should only be replaced with high-speed ones!

To replace the diode VS-60CPH03 will fit STTH6003CW, FFH30US30DN. All these diodes are analogues and are excellent for replacing each other. They are actively used in welding machines. Also suitable STTH6003 TV , but he has a different body ( ISOTOP), although if there is no other, then, if desired, you can contrive and screw it somewhere.

When installing diodes on a radiator, it is necessary to use thermal conductive paste (for example, KPT-8).

You shouldn’t be greedy, but you shouldn’t overly spread the paste on the area of ​​thermal contact. Apply a small, even layer of paste to the contact area of ​​the diode body and aluminum radiator. Then securely screw the diode housing to the radiator with a screw.

Installing diodes on a radiator should be taken seriously. During operation, the diodes get very hot and the slightest difficulty with cooling will cause them to overheat and fail.

When installing diodes, it is necessary to solder the connection points of the leads and contacts of the copper tracks as best as possible. This is very important, since the currents are simply huge and if you cheat, nothing good will come of it.

If during dismantling the copper coins and copper tracks were “torn off”, then they can be built up with tinned copper wire and soldered with high quality. Purely electrical contact not enough - soldering must be reliable.

After replacing the faulty diode, the device started working.

An archive with diagrams for welding machines TELWIN Tecnica 141-161, TELWIN Tecnica 144-164 and TELWIN Tecnica 150, 152, 170, 168GE can be downloaded. File size - 4.4 Mb.

Malfunctions of welding inverters are most often caused by either illiterate or careless operation, since these are quite reliable devices and there is simply nothing to break. However, it can also be the fault of the manufacturer who installed a low-quality part or performed a poor installation.
Let's try to generalize a little typical faults welding inverters and ways to eliminate them.

1. Unstable arc combustion or strong spattering of metal during the welding process.
This may be the result of an incorrectly selected . The manufacturer indicates recommendations for selection on the pack of electrodes. If such information is not available, it is worth using simplest formula: for 1 mm of thickness of a piece electrode it is necessary to apply from 20 to 40 Amperes of current.

2. Electrode sticking even with the anti-stick function.
Most often this is caused by the voltage in the supply network being too low, and in the case of a low-voltage welding machine, by the latter falling below the minimum when the load is connected.
Another cause of sticking is poor contact in the panel sockets. To fix it, just tighten the fasteners or fix the inserts.
The voltage drop may be due to the use of a power extension cord with a wire cross-section of less than 2.5 mm, which again leads to a decrease in the effective supply voltage of the welding machine. In addition, the reason may lie in the extension wire being too long. It is worth noting that if the wire length is over 40 meters effective work impossible - too big losses.
The cause of sticking can also be burnt contacts in the connections of the supply circuit, which again leads to a significant “drain” of voltage.

3. There is no welding, although all indicators work.
The first cause of the malfunction is overheating of the welding inverter. In the presence of warning lamp or indicator, their glow may not be noticeable if the welding inverter does not have an audible overheat signal.

A transistor in a welding inverter damaged due to overheating

Working transistor in a welding inverter

The second reason is a break in the welding cables, or spontaneous disconnection.
Third, failure of control parts. To eliminate the cause, you will have to open the case and first visually inspect the filling for damaged parts. Sometimes the reason lies in poor-quality soldering - it is enough to re-solder the parts.

4. Turn off the voltage when welding.
Most often caused by a malfunction of the switch itself or its inadequacy rated current. The switch must withstand current up to 25 A.

5. The overheat indicator lights up.
Excessive load, especially when thick layer dust inside the case. If the cooling fan malfunctions, the welding inverter usually does not turn on, although this may depend on the specific model.
Of course, in a short article it is impossible to describe in detail all the causes and possible malfunctions of welding machines. However, careful attention to the welding inverter used can prolong its “life” for a long time, and bring joy to the owner from work.

Welder running in after repair. Thermal control:

Radical repair of malfunctions of the welding inverter GYS 3200:

Equipment such as a welding machine has always been in demand. Especially if he small sizes, compact, operating at a voltage of 220 volts, which is very convenient when carrying out welding work in places where it is difficult to use bulky and powerful devices. For example, on construction sites, in car repair services, household appliances etc.

But, most importantly, the welding machine, the weight of which seems ridiculous for such equipment, sometimes it does not exceed 5 kg, due to its compactness and mobility it is easy to use when repairing personal equipment, construction individual houses, construction of some metal structures on summer cottages etc. In a word, such a welding baby will come in handy everywhere.

Now modern technologies allow to manufacture in wide range and a large number of compact and mobile welding machines that are used not only in industry, but also at home. You can practically buy them in any store for the sale of equipment. Big choice and the reasonable price of welding machines allow everyone to buy them without any problems.

Currently, welding machines of various models from the Latvian company Resanta are very popular. This equipment High Quality. In Russia, the demand for Resanta welding machines is very high. They are convenient to transport, because their size and weight allow you to transport equipment even in the trunk passenger car. And carry it over short distances by one person.

The advantages of Resanta were appreciated not only by professional welders, but also by amateurs who do not have sufficient experience in welding work.

The company produces two types of welding equipment: Resanta welding machine and Resanta welding inverter. The difference between them is that the first type is a transformer unit, and the second is an inverter unit. Both differ from each other in various respects.

However, no matter how reliable the device is, and no matter how much safety margin it has, sooner or later some part may fail and it will need repair. Just as there is no perpetual motion machine in nature, there are no perpetual mechanisms. Breakdowns are inevitable with both the Resanta welding machine and the Resanta inverter. Let's consider general signs and the reasons for both types of welding equipment from a Latvian company, leading to repairs.

Signs and causes of welding inverter breakdowns

Signs by which you can determine that the Resanta welding inverter repair required:

• electrode sticking
• instability electric arc
• lack of arc
• device overheating
• inverter does not turn on

Causes of malfunction

Electrode sticking occurs in the following cases:

• low voltage
• using an extension cord with a cross-section of less than 2.5 mm
• burnt contacts
• poor cable contact

Arc instability is caused by:

• incorrect adjustment of welding current
• mismatch between the type and diameter of electrodes

Lack of arc in caused by the following reasons:

• cable break
• inverter overheating
• lack of "mass"
• failure of a printed circuit board, where one or even several parts have failed

Device overheating can happen when:

• he works long time at full load without interruption
• cooling fan failed
• there is a large layer of dust on the printed circuit board parts

Reasons when the inverter does not start after pressing the “Start” button. those. does not start working, may be as follows:

• absent completely or low voltage nutrition
• something is faulty: cable, socket or switch
• Some element has broken down on the printed circuit board
• extension cord needs to be replaced

Welding machine breakdowns

Causes of breakdowns, because of which often welding units are being repaired:

Any manufacturer values ​​his reputation and will not produce low-quality products. However, no matter how good the assembly of the same welding machine, during operation from vibration, constant transportation, etc., the contacts on terminal blocks, to which the welding cables are connected, weaken. And as a result, strong heating of the parts occurs at the junction points, which leads to their destruction and short circuit in the network, and therefore to repair. To prevent this, you need to regularly monitor the contacts on the terminals, and, if necessary, sort out and clean the connecting contacts, thereby ensuring tight contact of all parts.

It often happens that the welding machine suddenly he can switch off on his own. And this happens because in the high voltage circuit there is short circuit. In this case, it is necessary to identify the defective location and eliminate the malfunction.

Loosening of the bolts tightening the transformer plates, overloads in the operation of the transformer unit of the welding machine, as well as loosening of the core or the mechanism for moving the coils lead to overheating of the unit’s transformer.

If the welding machine overheats, then it needs to take a “break”. Equipment overheating is possible during his intense work. In such cases, to prevent the unit from malfunctioning, it is recommended to reduce the operating current or use electrodes of a smaller diameter, otherwise the matter may end in repair.

If the machine does not “pull”, the reason should be sought in the mains voltage or the welding current regulator.

Main types of repair work

Some minor breakdowns of Resanta can be repaired yourself, without the help of specialists. But it also happens that serious repairs are required. In this case it is best contact service center . There, for example, they can make a replacement:

• fan
• inverter boards
• transformer
• diode rectifier
• capacitors
• and other details

And carry out repairs:

• control boards
• power supply
• control module
• IMS module
• main board

To reduce repairs to your welding machine, try to operate it correctly. And then you won’t need to spend money on repairs often.

The welding inverter provides good quality carrying out welding work, creating for the welder the maximum comfortable conditions for work. However, these advantages lead to increased complexity of its design. This may cause various malfunctions welding inverter and reduces its reliability.

Features of inverter repair

Unlike conventional welding machines, which are electrical products, an inverter for welding is electronic device. Consequently, diagnostics and repair of inverter welding machines are carried out by checking the operating condition of diode bridges, transistor connections, zener diodes and other parts that are included in the electronic circuits. In this case, you need to have skills in handling oscilloscopes, voltmeters, multimeters and others measuring instruments.

Home distinctive feature When repairing a welding inverter, it is difficult to determine the nature of the breakdown and detect the failed part. Therefore, it is very often necessary to diagnose all nodes electrical diagram.

Based on the above, we can conclude that it is necessary to have minimal knowledge in the field of electronics and be able to understand the design of electrical circuits. If such skills and abilities are missing, then take on do-it-yourself repair Such a device is not recommended so as not to waste extra effort and time.

Operating principle of the inverter

Principle of operation inverter devices consists of sequential (step-by-step) transformation of the incoming electric current signal:

• the process of rectifying incoming network currents using a special rectifier;
• the process of converting rectified currents into alternating high-frequency signals;
• process of reducing currents from high voltage up to the welding voltage occurring on the power transformer;
• transformation alternating current with high frequency D.C., occurring using the output rectifier.

To perform such operations, the welding inverter design has several modules with electronic stuffing. The main module is the input current rectifier. Then there is a control board on which transistors (switches) are located, and it ends with a rectifier for the output signals.

At the same time, in devices different manufacturers having different models, the layout of the unit components can be very diverse, but the installation of the main components will always remain unchanged.

Therefore, knowing the basic operating principle of such units and the location of the main modules of their design, it is possible to diagnose possible faults and carry out the necessary repairs.

Types of main faults

If the welding inverter fails, the first thing you should do is check its transistors, since they are one of the most weak points such units. Initially, you should carry out visual inspection transistors. Such a broken part is very easy to identify: it has a broken or cracked case with burnt-out leads at the solder points on the board. This part needs to be replaced immediately.

New transistors should be installed on a special thermal paste. It will ensure heat removal from the transistor to a radiator made of aluminum. But very often a visual inspection does not reveal faulty elements, then you should make a “diagnosis” using a multimeter.

Replacement faulty elements carried out according to precisely specified parameters. In some cases, it is possible to supply analogue parts, and the required parameters can be determined from the datashift. If replacing the burnt-out transistors does not help, you need to move on to further diagnostics.

IN normal mode operation, transistors cannot simply fail; most likely, this is due to the incorrect operation of other elements. Most often this is the driver. It is checked with an ohmmeter. If faulty parts are found, they must be removed and replaced with similar parts.

Then the input and output current rectifiers, which consist of diode bridges, are checked. They are installed on the radiator and are reliable components for welding inverters. But they can also fail. Their functionality is checked using a voltmeter.

Control board fault

It is best to check diode bridges by unsoldering the wires from them and then detaching them from the board. This can make everything easier further work and there will be no doubt when a short circuit occurs in the entire inverter circuit.

The check follows a fairly simple algorithm. It is necessary to “ring” the entire group of parts. If a “short” is detected, then you should search for a broken diode. Once it is detected, the diode should be carefully removed and replaced.

If, after carrying out all the above steps, the welding machine still does not work, you should test the control board. It monitors the operation (control) of the keys. The reliability of all equipment will depend on the reliability of such a board.

To carry out competent and qualified repair of the inverter, it is necessary to check for the presence of the necessary signals that produce its operation. These signals must be sent to the gate buses of the key module. You can perform a similar check using oscilloscopes.

Periodically, high heating of the inverter housing may occur. This may be due to violations of the rules for using the unit and wrong choice values ​​of current used for welding. This can also occur when the electrodes are incorrectly selected or the unit is operated for too long. To avoid such difficulties when using the inverter, it is necessary to observe optimal modes works that are specified in the technical passport.

You can fix inverter malfunctions yourself, but this can only be done if you have the necessary diagnostic tool and experience in using it. Otherwise, it is better to seek help from specialists.

Inverter welding machines are becoming increasingly popular among welders due to their compact size, low weight and reasonable prices. Like any other equipment, these devices can fail due to improper use or due to design flaws. In some cases, you can repair inverter welding machines yourself by studying the design of the inverter, but there are breakdowns that can only be repaired in a service center.

Welding inverters, depending on the model, work like household ones electrical network(220 V) and three-phase (380 V). The only thing that needs to be taken into account when connecting the device to a household network is its power consumption. If it exceeds the capabilities of the electrical wiring, then the unit will not operate if the network is drained.

So, the inverter welding machine includes the following main modules.

How does an inverter work?

Below is a diagram that clearly shows the principle of operation of a welding inverter.

So, the operating principle of this welding machine module is as follows. The primary rectifier of the inverter receives voltage from the household electrical network or from generators, gasoline or diesel. The incoming current is alternating, but as it passes through the diode block, becomes permanent. The rectified current is supplied to the inverter, where it is converted back into alternating current, but with changed frequency characteristics, that is, it becomes high-frequency. Next, the high-frequency voltage is lowered by a transformer to 60-70 V with a simultaneous increase in current. At the next stage, the current again enters the rectifier, where it is converted into direct current, after which it is supplied to the output terminals of the unit. All current conversions controlled microprocessor unit management.

Causes of inverter failures

Modern inverters, especially those made on the basis of an IGBT module, are quite demanding in terms of operating rules. This is explained by the fact that when the unit is operating, its internal modules generate a lot of heat. Although radiators and a fan are used to remove heat from power components and electronic boards, these measures are sometimes not enough, especially in inexpensive units. Therefore, you need to strictly follow the rules that are indicated in the instructions for the device, which imply periodically turning off the unit to cool down.

This rule is usually called “On Duration” (DS), which is measured as a percentage. Without observing the PV, the main components of the device overheat and fail. If this happens to a new unit, then this breakdown is not subject to warranty repair.

Also, if the inverter welding machine is working in dusty rooms, dust settles on its radiators and interferes with normal heat transfer, which inevitably leads to overheating and breakdown of electrical components. If the presence of dust in the air cannot be eliminated, it is necessary to open the inverter housing more often and clean all components of the device from accumulated contaminants.

But most often inverters fail when they work at low temperatures. Breakdowns occur due to the appearance of condensation on the heated control board, resulting in a short circuit between the parts of this electronic module.

Repair features

A distinctive feature of inverters is the presence of an electronic control board, so only a qualified specialist can diagnose and repair faults in this unit. In addition, diode bridges, transistor units, transformers and other parts of the electrical circuit of the device may fail. To carry out diagnostics yourself, you need to have certain knowledge and skills in working with measuring instruments such as an oscilloscope and a multimeter.

From the above, it becomes clear that, without the necessary skills and knowledge, it is not recommended to start repairing the device, especially electronics. Otherwise, it can be completely damaged, and repairing the welding inverter will cost half the cost of a new unit.

Main malfunctions of the unit and their diagnostics

As already mentioned, inverters fail due to the impact on the “vital” units of the device external factors. Also, malfunctions of the welding inverter can occur due to improper operation of the equipment or errors in its settings. The most common malfunctions or interruptions in the operation of inverters are:

The device does not turn on

Very often this breakdown is caused malfunction network cable apparatus. Therefore, you first need to remove the casing from the unit and ring each cable wire with a tester. But if everything is in order with the cable, then more serious diagnostics of the inverter will be required. Perhaps the problem lies in the standby power supply of the device. The method of repairing the “duty room” using the example of a Resanta brand inverter is shown in this video.

Welding arc instability or metal spattering

This malfunction may be caused incorrect setting current strength for a certain electrode diameter.

Advice! If there are no recommended current values ​​on the packaging for the electrodes, then it can be calculated using the following formula: for each millimeter of equipment there should be a welding current in the range of 20-40 A.

It should also be taken into account welding speed. The smaller it is, the lower the current value must be set on the control panel of the unit. In addition, to ensure that the current strength corresponds to the diameter of the additive, you can use the table below.

Welding current is not adjustable

If not regulated welding current, the reason may be regulator failure or a violation of the contacts of the wires connected to it. It is necessary to remove the unit casing and check the reliability of the conductor connections, and, if necessary, test the regulator with a multimeter. If everything is in order with it, then this breakdown can be caused by a short circuit in the inductor or a malfunction of the secondary transformer, which will need to be checked with a multimeter. If a malfunction is detected in these modules, they must be replaced or rewound by a specialist.

High power consumption

Excessive power consumption, even if the device is without load, most often causes turn-to-turn short circuit in one of the transformers. In this case, you will not be able to repair them yourself. You need to take the transformer to a mechanic to rewind it.

The electrode sticks to the metal

This happens if the network voltage drops. To get rid of the electrode sticking to the parts being welded, you will need to correctly select and configure the welding mode (according to the instructions for the device). Also, the voltage in the network may sags if the device is connected to an extension cord with a small wire cross-section (less than 2.5 mm 2).

Often, a drop in voltage causing electrode sticking occurs when using a power extension cord that is too long. In this case, the problem is solved by connecting the inverter to the generator.

Overheat light on

If the indicator is on, this indicates overheating of the main modules of the unit. Also, the device may turn off spontaneously, which indicates when thermal protection is triggered. To prevent these interruptions in the operation of the unit from occurring in the future, you again need to adhere to correct mode ON duration (DS). For example, if duty cycle = 70%, then the device should operate in the following mode: after 7 minutes of operation, the unit will be given 3 minutes to cool down.

In fact, various breakdowns and there can be quite a lot of reasons that cause them, and it is difficult to list them all. Therefore, it is better to immediately understand what algorithm is used to diagnose a welding inverter in search of faults. You can find out how the device is diagnosed by watching the following tutorial.