Time：2016-6-28 17:42:34 Views：
Instrumentation circuit maintenance in the electronics category of the company has always been an indispensable part of. Because only through it can make the original unqualified products in the final factory. However, maintenance instrumentation is also the most complex part of the electronics company. Because it is not only to be applied to many electronic professional knowledge, and sometimes also need to have a wealth of experience in the field.
1, percussion hand pressure method
Instrument operation is often encountered when the bad phenomenon, this phenomenon most is due to poor contact or weld caused. For this situation, it can be used to tap and hand pressure.
The so-called "stroke" is on the position of fault may occur through a small rubber hammer or other object struck lightly tapping the plug-in board or a component to see whether caused by error or malfunction. The so-called "hand pressure" is when the fault occurs, the power supply on the plug and the plug and the plug and re hand press firmly, and then try to try to find out whether it will eliminate the fault. If you find a knock on the casing is normal, and then beat it is not normal, it is best to re insert all the joints in prison and try again, if the brain is not successful, had to find another way.
2, observation method
Using sight, smell, touch. Some time, damaged components will change color, foaming and burnt spots appear; burn the device will produce some special smell; short circuit of the chip will burn; with the naked eye can be observed at the weld or sealing.
3, elimination method
The so-called exclusion method is by some device plug-in board, plug inside the machine to determine the cause of the malfunction. When the removal of a plug-in board or device after the return to normal, indicating that the fault occurs in there.
4, replacement method
Requires two units of the same type of equipment or adequate spare parts. With a good spare parts and components on the fault plane for the replacement, if the failure to eliminate.
5, contrast method
There are two instruments of the same type, and one is in normal operation. Using this method also has the necessary equipment, for example, a universal meter, oscilloscope, etc.. According to the comparison of the nature of the sub, voltage comparison, waveform comparison, static impedance comparison, output comparison, current comparison, etc..
The specific method is: to have the fault of the instrument and the normal instrument running in the same situation, and then detect some points of the signal and then compare the measured two groups of signals, if there are different, then you can determine the fault out here. This approach requires maintenance personnel with considerable knowledge and skills.
6, lifting temperature method
Sometimes, the instrument and meter work for a long time, or in the summer working environment temperature is higher, it will be a failure, check the normal shutdown, stop for some time and then normal, and after a while there is a failure. This phenomenon is due to the poor performance of individual IC or components, the high temperature characteristic parameters can not meet the requirements. In order to find out the cause of the failure, the method can be used.
The so-called cooling, that is, when the failure occurs, the use of cotton fiber will be a failure of alcohol in the parts of the failure to wipe, to cool down, to observe whether the elimination of failure. The so-called warming is artificially the environmental temperature, such as electric soldering iron placed near suspicious sites (note that must not be temperature rise too high so that the damage to the normal device) look at whether a fault is occurring.
7, riding shoulder method
Parallel connection method. Put a good IC chip in to check on the chip, or good (resistance, capacitor, diode, triode, etc.) components and to check the components parallel and maintain good contact, if the fault from from within the device open circuit or poor contact causes, the this method can be ruled out.
8, capacitor bypass method
When a circuit produces a relatively strange phenomenon, such as the display chaos, can be used to determine the circuit part of the fault of the capacitor bypass method. The capacitor is connected to the power supply and ground of the IC; and the transistor circuit is connected with the input end of the base and the output end of the collector, and the effect of the fault phenomenon is observed. If the capacitor bypass input is not valid and the output end of the bypass is lost, the fault occurs in the circuit.
9, state adjustment method
Generally speaking, before the failure is not determined, do not touch the circuit in the components, especially the adjustable device is more so, such as the case of a potentiometer, etc.. However, if prior to the reference measures taken in advance (for example, do not touch the position before the first to do a good position to mark or measure the value of the voltage or resistance, etc.), or to allow the need to touch. Maybe sometimes the fault will be removed after the change.
10, isolation method
The failure isolation method does not require the same type of equipment or spare parts for comparison, and it is safe and reliable. According to the flow chart of fault detection, segmentation and bounding step by step to narrow the scope of the fault, and then with the signal contrast, parts exchange and other methods, the general will soon find the fault of the instrument.
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