Teach you ten recruit diagnosis instrument failure easily

Usq magnetic flap | | glass thermometer thermometer floating ball | | glass thermometer thermometer two-color thermometer

' Abstract 】 In this paper, the instrument fault summary of our company for many years experience in maintenance and you learn together, hope to help you in the future work.

instrument circuit maintenance in the electronics company has always been an indispensable part of. Because only by it can make originally not qualified products factory in the end. However, maintenance is also the most complicated part of electronic company. Because it not only be applied to many electronic professional knowledge. Sometimes also needs to have rich experience in site.

1, the observation method using visual, smell and touch. To some, the damaged element will change color, blister or charred spots; The smell of burning device will produce some special; Short circuit of the chip will be hot; With the naked eye can observe virtual soldering or desoldering.

2, the so-called exclusions deduction is through some board inside the machine, pull device to determine the cause of the problem. When removing a card or device instrument returned to normal, after failure there.

3, on the hand pressure we use instrument, often encounter the phenomenon of instrument operation and downs, this phenomenon is mostly caused by poor contact or virtual welding. In this case with hand pressure can be used. The so-called & other; Percussion & throughout; Is on the part of the fault may be produced by small rubber ð ¨ +  head or other tap tap the board or components, see if it will cause error or downtime The so-called & other; Hand pressure & throughout; Is when failure occurs, turn off the power to connect components and plug and seat back pressed firmly with the hand, it will try to eliminate the fault. Tapping the chassis is normal, if found again knock again not normal, it's best to put all joint stuck to try again, if you don't succeed, to think of other ways.

4, replacing method requires two same instrument or have enough spare parts. Will be a good spare parts with the same components of fault on board to replace, the fault is eliminated.

5, contrast method requires two sets of the same model of instrument, and there is a normal operation. Using this method also has the necessary equipment, for example, multimeter, oscilloscope, etc. According to the comparison of the nature of the points, comparison, waveform comparison, comparison of static impedance, voltage output comparison, comparison of current and so on. The specific method is: let the defective instrument and normal running in the same situation, and then some detection point of signal be comparative test of two groups of signal, and if there is different, you can conclude that fault out here. This approach requires maintenance personnel have considerable knowledge and skills.

6, cooling method, sometimes the instrument work a long time, or working environment at high temperature in summer can appear fault, check normal shutdown, stop for a period of time it is normal again, fail again in a moment. This phenomenon is due to individual IC or component performance is poor, temperature characteristic parameters are not up to standard requirements. In order to find out the cause of the problem, can use litre cooling method. So-called cooling is when failure occurs, cotton fiber to anhydrous alcohol in wiping may be out of order, make its cool, observe whether fault is eliminated. So-called warming is artificially environment temperature, such as soldering iron nearer questionable parts ( Attention must not will increase temperature too high, so that damage the normal device) Whether tested failure.

7, ride a shoulder on shoulder also called parallel method. Put a piece of good IC chip in to check the chip, or the good components ( Resistance capacitance, diode, triode, etc. ) With components in parallel to check, maintain good contact, if internal open circuit fault from the device or poor contact, that is the way that can be ruled out.

8, capacitance bypass method when a circuit produces quite strange phenomena, such as display confusion, can use the capacitance bypass method about the fault circuit part. The capacitance jumper in the power of the IC and end; Jumper in the base of transistor circuit input or collector output, to observe the effects of the failure phenomenon. If capacitance bypass invalid input and the output of the bypass it end failure phenomenon disappear, then determine the fault occurs in the primary circuit.

9, status of control in general, in front of the fault is not sure, don't touch the components in the circuit, this is particularly true of the adjustable type device, potentiometer, etc. But if after reference measures in advance, For example, in touch before not well location marker or measured voltage or resistance, etc. ) And, if necessary, or allowed to touch. After may change sometimes fault elimination.

10, isolation method fault isolation method does not require the same type of equipment or spare parts, and safe and reliable. According to the flow chart of fault detection, demarcated by diminishing the fault search scope, combined with methods of signal contrast, exchange of parts, the general will soon find fault.

the author: golden lake thermometer factory automation instrument co. , LTD. { Magnetic flap thermometer} For reprint please indicate the here