customer usually buy instrument main consideration has 3 points: one is the price, the second is the quality of the products, the third is how about after-sales service, good after-sale, in large part to attract customers, the product maintenance, first look at the appearance, check whether had touched, it is essential to check next, whether can normal boot.

instrument circuit maintenance in the electronics company has always been an indispensable part of. Because only by it can make originally not qualified products zui throughout the factory. However, maintenance is also zui as part of the complex in electronic company. Because it not only be applied to many electronic professional knowledge, sometimes also needs to have rich experience in the scene. Below is my personal summary of maintenance experience for many years.

1, the hitting hand pressure

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 tap is on the part of the fault may be produced, through a small rubber ð ¨ +  head or other tap tap the board or components, see if it will cause error or downtime The so-called hand pressure is when failure occurs, turn off the power to connect components and plug and seat after again pressed firmly in hand, it is will try to eliminate the fault. Tapping the chassis is normal, if found again knock again not normal, all joint heavy stuck to try first, if the trouble is not successful, had to want to other measures.

2, observation method, using the 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.

3, the so-called functional exclusions 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.

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, comparative law requires two same instruments and meters, 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.