Analysis of several methods commonly used in textile instrument maintenance1

Textile instruments, as a type of instrument often tried by textile enterprises, are frequently used in daily production. Textile instruments will inevitably lead to wear and tear during the trial process. How should people face and maintain some common faults? ? Returning to the factory for maintenance will waste a lot of time for the company. The engineer of (Hong Kong) Co., Ltd. briefly introduces some methods. First, the observation method using sight, smell, touch. Sometimes, damaged components will discolor, blister or have burnt spots; burnt components will produce some special odor; shorted chips will become hot; virtual soldering or desoldering can also be observed with the naked eye. . 2. Knocking hand pressure method When we use the instrument, we often encounter the phenomenon that the instrument is running well and badly. Most of this phenomenon is caused by poor contact or virtual welding. In this case, tapping and hand pressing can be used. So-called“tap”It is to tap the plug-in board or component lightly with a small rubber hammer or other knocking object to see if it will cause an error or downtime. so-called“hand press”That is, when a fault occurs, after turning off the power, press the plugged parts, plugs and sockets firmly by hand again, and then turn on the power to try whether the fault will be eliminated. If you find that tapping on the casing is normal, and hitting it again is abnormal, it is best to reinsert all the connectors and try again. 3. Comparison method It is required to have two instruments of the same type, and one of them is in normal operation. Using this method also requires the necessary equipment, such as a multimeter, oscilloscope, etc. According to the nature of comparison, there are voltage comparison, waveform comparison, static impedance comparison, output result comparison, current comparison and so on. The specific method is: let the faulty instrument and the normal instrument operate under the same conditions, and then detect the signals of some points and then compare the two groups of signals measured. If there is a difference, it can be concluded that the fault is here. This method requires the maintenance personnel to have considerable knowledge and skills. Fourth, the elimination method The so-called elimination method is a method of judging the cause of the failure by plugging in some plug-in boards and devices in the machine. When the instrument returns to normal after a plug-in board or device is removed, it means that the fault occurs there. 5. Capacitor bypass method When a certain circuit produces a strange phenomenon, such as the display confusion, the capacitor bypass method can be used to determine the part of the circuit that is likely to fail. Connect the capacitor across the power supply and ground of the IC; connect the transistor circuit across the base input or collector output to observe the effect on the fault phenomenon. If the failure phenomenon disappears when the capacitor bypass input terminal is invalid and its output terminal is bypassed, it is determined that the fault occurs in this stage of the circuit. 6. Replacement method It is required to have two instruments of the same model or have enough spare parts. Replace a good spare with the same component on the faulty machine to see if the fault is eliminated. Seven, heating and cooling method Sometimes, the instrument works for a long time, or when the temperature of the working environment is high in summer, it will malfunction. Shut down and check normally, stop for a period of time and then restart it normally, and then malfunction again after a while. This phenomenon is due to the poor performance of individual ICs or components, and the high temperature characteristic parameters do not meet the index requirements. In order to find out the cause of the failure, the heating and cooling method can be used. The so-called cooling is to use cotton fiber to wipe the anhydrous alcohol on the part that may fail to cool down when the failure occurs, and observe whether the failure is eliminated. The so-called temperature rise is to artificially raise the ambient temperature. For example, use an electric soldering iron to approach the suspicious part (be careful not to raise the temperature too high to damage the normal device) to see if the fault occurs. Eight, the shoulder riding method The shoulder riding method is also called the parallel method. Put a good IC chip on the chip to be checked, or connect good components (resistor capacitors, diodes, transistors, etc.) in parallel with the components to be checked, and maintain good contact. If the fault comes from the internal open circuit of the device or Reasons such as poor contact can be ruled out by this method. Nine, state adjustment method Generally speaking, before the fault is determined, do not touch the components in the circuit casually, especially the adjustable devices, such as potentiometers. However, if the double reference measures are taken in advance (for example, the position is marked or the voltage value or resistance value is measured before being touched), it is still allowed to be touched if necessary. Maybe after the change sometimes the glitch will go away. 10. Isolation method The fault isolation method does not require the same type of equipment or spare parts for comparison, and is safe and reliable. According to the fault detection flow chart, the division and encirclement gradually narrow the fault search range, and then cooperate with methods such as signal comparison and component exchange to find the fault location very quickly. More about Textile Instruments: http://www.standard-groups.com/TextileGarment/