DIY fubag in 160 inverter repair

In detail: do-it-yourself repair of the fubag in 160 inverter from a real master for the site my.housecope.com.

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The Fubag in160 is similar to the GYSMI 161 circuitry.

I continue to repair IN160, the NCP1055 microcircuit was replaced from another batch, dead transistors Q11S02 = Q11S01 = BSR14, replacement from a donor, dead optocouplers U12X01, U41X01. The duty room has started up, the fan is spinning. The S17LITE05 processor does not issue a PWM signal, therefore the power section does not start. I took off the force, unsoldered the comb, I did not find any broken elements.
Does anyone have a power section diagram?

S17LITE05 was thrown from the donor, there are no changes, not the fact that it is whole.

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Rummaged in the internet on one forum, I found that the matter could be in the firmware or calibration. I sin on it for now. Disassemble again, oh, how not a hunt! And so, when soldering the bridge from the main board, I damaged one track - I had to restore it with a MGTF wire. The design is just hellish) Please help, ipaSoft.
- 1) Check this contact very well. Pay attention if there is no burnout of the interlayer bushings in the printed circuit board.
  2) Connect a 100 W light bulb as a load, only apply the load after turning on the device, and not before.
  3) If the voltage subsided, or rather, decreased to 0, then the contact between the rack and the board is bad. Connect the lamp to the rack. Repeat measurements.
  4) If the voltage sags, climb the oscillator onto the motherboard and check the signal on L6386: between 8 and 9 feet, between 12 and 13 feet.
  a) If there are pulses, then this is not firmware or calibration. Two options
  b) Both output diodes are broken. You can check with a tester.
  c) The amplifier stage from the complementary pair on the module is faulty (decoupling L6386 with MOSFET keys)
  
  Further, a huge complex branch for further troubleshooting of this machine. But I will not dump everything, I will listen to your measurements.
  
  Black Fire wrote:
  forget about the potential for failure of the power supply unit and whistling.
  
  My second year is whistling robust after a slight fall. Is it going to die soon?
  
  Exuberant wrote:
  My second year is whistling robust after a slight fall. Is it going to die soon?
  
  We're talking about a different whistle. Inverter series 130/160/170 whistle slightly when off (features of the auxiliary power supply unit)
  In your case - but who knows how much - maybe it will outlive us (you can't tell without looking)
  
  as an electronics engineer, I would advise when reworking switching power supplies
  use microcircuits that have the same operating frequency and are turned on
  according to typical schemes from datasheets found for example on ">,
  
  otherwise whistling, static chirping and output voltage jumps are possible
  in case of interference during welding in such a converted unit with unpredictable consequences
  for an expensive power unit,
  for example, in the recommended replacement NCP1055ST100T3G-TNY278PG, the first microcircuit
  operates at 100, and the second at 132kHz (like NCP1055ST136, operating at 132kHz),
  
  hence the question is whether it works without problems
  over the entire operating range of voltages and temperatures?
  
  and another very important is the snubber chain (according to the datasheet), the limiter in Russian, connected in parallel
  primary winding - the elements of this circuit operate in maximum mode
  and it is desirable to replace them with high-quality and powerful ones, which manufacturers often do not do (do not even install!)!
  
  electrolytic capacitors of rectifiers of secondary windings change to jamikon, green,
  with low series resistance (LowESR), which will save you a bunch of additional problems,
  
  rinse thoroughly from the flux and, after checking, cover the installation with heat-resistant varnish, even furniture,
  the tsapon peels off in some hot places, although where it is not hot, it will
  
  Basically, devices with defective microcircuits do not react in any way to attempts to turn on, but there were rare cases when Fubag IN160 inverter shutdown with warm-up, after a few seconds it turned on, then turned off again, and clicked. In this case, it turned out to check the microcircuit by turning on the device and, while clicking, gently leaning a cotton swab moistened with alcohol against it, the clicking immediately stopped and the inverter worked normally until the alcohol dried out.
  
  Sometimes, after opening the device and external examination, such defects of the NCP1055B microcircuit are visible, one might say, with the naked eye.
  
  Often the microcircuit breaks down, by itself, without affecting the vital surrounding elements. Something she has personal problems with the tightness of the case. In such cases, it is sufficient to replace only the microcircuit. We will consider this option.
  
  First of all, we will clear the place from the killed microcircuit.
  
  It makes no sense to put it in the SOT-223 case again, since they are unreliable. Better to somehow contrive. and receive the FEATHER BIRD. no set the microcircuit to DIP-8.
  
  Comparing the conclusions of this microcircuit by the datasheet, we bend them in this way.
  
  If everything is done correctly and the surrounding components are intact, which is better to be sure by using the circuit in advance and checking them, then the device turns on immediately and works great.
  
  On the forums, you can find options for replacing the NCP1055B with the TNY268 with a slight alteration of the circuit.
  remont22
  Posted 02 April 2011 - 01:57
  PWM NCP1055P100.
  From another forum.
  I fixed another deadhead, with an "improved" duty feeder on the NCP1055 that explodes all the time.
  In general, this product can be exchanged for a TNY268 in a DIP-8 package. I soldered it onto a small breadboard, and connected it to the circuit with short conductors. How to do this is clear from the comparison of the documentation for these 2 mikruhi. The bypass kander (10mk) is changed to 0.1mk. A source.
  
  Which option to choose is at your discretion.
  
  Attention!
  Be careful when repairing the welding inverter with your own hands, the responsibility lies with you.
  
  Repair of welding inverters from Fubag and other manufacturers.
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    - The inverter is on, its indicators are on, but no welding. Most often this occurs due to overheating of the device, when the glow of the control indicator or lamp (if available) is hardly noticeable, and the inverter does not have a sound signal. The second reason is spontaneous disconnection of welding cables or their breakage (damage).
    - Turning off the mains voltage during welding - an incorrectly selected circuit breaker is installed in the electrical panel. This device must be rated for currents up to 25 A.
    - The inverter does not turn on - low voltage in the network, insufficient for the operation of the device.
    - Stopping the operation of the inverter during prolonged welding - most likely the temperature protection has tripped, which is not a malfunction. After a pause of 20-30 minutes, welding can be resumed.
    If the visual inspection did not bring any result, then proceed to ringing (testing) the parts using an ohmmeter or multimeter. The most vulnerable elements of inverter modules are transistors. Therefore, the repair of the apparatus usually begins with their inspection and verification. Power transistors rarely fail by themselves - as a rule, this is preceded by a failure of the elements of the "swinging" circuit (driver), the details of which are checked first. In the same way, by means of the tester, they call the rest of the board elements.
    
    On the board, it is necessary to check the condition of all printed conductors for the absence of breaks and burns. The burnt areas are removed and the jumpers are soldered, as in the case of breaks, with a PEL wire (with a cross section corresponding to the board conductor). You should also check and, if necessary, clean (with a white eraser) the contacts of all connectors in the device.
    
    Rectifiers (input and output), which are conventional diode bridges mounted on a heatsink, are considered to be quite reliable components of inverters. But sometimes they fail.It is most convenient to check the diode bridge after unsoldering the wires from it and removing it from the board. If the entire group of diodes rings for a short time, then you should look for a broken (faulty) diode.
    
    The key management board is checked last. In the inverter module, this is the most complex element and the operation of all other components of the apparatus depends on its functioning. The final stage in the repair of the inverter welding device should be to check the presence of control signals coming to the busbars of the gates of the key block. Diagnose this signal using an oscilloscope.
    
    In cases that are unclear and more complex than those described above, the intervention of specialists will be required. Trying to fix the malfunction yourself is not worth it, especially when the inverter is under warranty.
    
    The presented machine produces welding using electrodes and direct current.
    
    With this welding machine, you can weld all kinds of electrodes from rutile to stainless steel.
    
    As for the voltage required for the operation of the tool, it is 220 volts.
    
    In order for the device to perform its direct functions, it must be connected to a 16, 20 or 25 A socket with a voltage of 220 volts.
    
    Then you should attach the earth clamp and the electric holder to the inverter, guided by the information about the polarity, which corresponds to the type of electrode used.
    
    The device will turn on the moment the potentiometer is set to the required current.
    
    The scheme - inverter in 160 fubag can work in two modes - MMA and TIG. When applying the first mode, do not forget to follow the existing welding rules.
    
    In addition, do not turn off the device immediately after stopping welding, leave it on in order to allow it to cool sufficiently.
    
    When the yellow indicator lights up, it means that the thermal protection has tripped. Please note that the cooling period for the tool is approximately 5 minutes.
    
    When using TIG mode, connect the clamp of the earth cable to the socket with positive polarity and insert the valve torch into the socket with negative polarity.
    
    Then connect the gas hose from the cylinder to the tool and set the required pressure. After that, proceed to adjust the desired intensity using the potentiometer.
    
    Remember that during the operation of the welding machine, the inverter in 160 fubag diagram cannot be viewed at work. Certain safety rules must be followed.
    
    Always wear protective clothing, mask or goggles and other protective equipment when using the tool to avoid damage to skin and eyes.
    
    In addition, do not under any circumstances come into contact with exposed inverter cables that carry current, as well as with the electric holder and the surface to be welded.
    
    Moreover, do not allow contact with water while using the tool, as well as fumes and gases generated during the welding process, as they can harm your health.
    
    Among other things, take care not only of your own safety, but also of the safety of those around you, so make sure that there are no other people on the work site.
    
    These are basic safety rules. You can familiarize yourself with all existing standards in more detail by carefully studying the instructions for this welding machine.