Replace before doing other tests on the integrated circuit

Replace before doing other tests on the integrated circuit

Has used replacement before the law, should be possible to use other, more simple way to check the quality of the integrated circuit judge. Do not rework, particularly large-scale integrated circuits, because, after all, is a troublesome thing, but also easy to scorch the circuit board, and only use other methods difficult to make accurate judgments, and to think that there is sufficient reason to doubt the integrated circuit has been worst case, only try substitution.

Demolition of integrated circuits in the weld can not be rushed, but can not plug the pin chaos. In general electric iron removal process (preferably constant temperature soldering iron) and absorption tin. ON-Camera Field Monitor In the case of no special tools, electric soldering iron can melt the lead solder with a medical needle immediately set to open the tin, when one by one pin to clamp the open, integrated set out, of course, other methods, there is not a an introduction. The goal is to remove from the circuit board will be integrated under the condition of the board as much as possible to minimize the extent of damage.

In addition to ICs, other components are very easy to replace, usually with good components instead of only the components of the doubt, here to say a special substitution method is to use the suspected bad components instead of to a good machine, look normal machine is still working to reduce the scope of anti-failure to determine point of failure. This method is usually only a small number of incurable diseases in check until used. For example: checking a component of a problem is suspected, but no precise instruments to measure its quality, then the components can be loaded into doubt a good machine up again, in order to determine whether the suspected damage to the components. Therefore have the same kinds of inspection methods or can be substituted in the circuit, replacing it is also more cumbersome, the general Hing difficult to exclude the issue of soft failure or using this method.


the current detection method

Current detection methods, there are two, one is direct measurement, the other is the indirect measurement. Direct measurement is to meter the appropriate string into the current file directly a measure of the circuit. Indirect measurement of a circuit by measuring the voltage drop on the resistance to the current value of estimated indirectly. The advantages of this method into the circuit without strings, while measuring the current size of the meter's range is not subject to restrictions, is also very convenient to use.

blind welding method

In the actual repair process, often leading to the monitor faced the Weld situation does not work. Due to the production of circuit boards are now tin soldering, the solder joint is thinner, more prone to this problem. Especially the use of old machines for many years more susceptible to cold solder joint. Weld points can really find is not necessarily an easy thing, ON-Camera Field Monitor and some may take a few days are difficult to exclude, especially in the user home maintenance is also easy to make users unhappy. At this time try not blind anti-welding method, can be suspected of Weld welding points one by one again. Since this approach with a certain blindness, so called "blind welding method."

local heating, cooling method

Most components are color displays work in high voltage, high current job status, the work of the components require a higher temperature, the cooler and heat is different, and the temperature change is the work of the state through the components shown , especially the relatively poor high-temperature parameters of the components is more evident. According to this feature can be used in the repair process, local heating and cooling components are suspected, so that failures fully exposed. Determine the faulty components, to eliminate the fault position.

The method for ambient temperature or in part, due to temperature rise caused by the delay of the soft failure and poor thermal stability of the components detected through the current large transistors, capacitors and other significant effects. Some machines, such as just-machine is a normal, working for some time, and the old play again. At this time we have special electric soldering iron or a hairdryer appropriate heating components, if the fault, suggesting that the "source of the problem" is the component; also work for some time when the machine fails, use cotton dipped in absolute alcohol was suspected of cooling components to see if the fault disappears, if the failure to disappear, then the fault is the source of the components.

By heating or cooling temperature to the attention of not more than the allowed range of components, can not heat up too high or too low temperature will damage the components.

sub-cut method

Sub-cut method, that is, repair process, through the plug pulled out part of the transfer or disconnect a circuit, and some can get rid of some components of a circuit or to narrow the scope of failure, and finally find out the fault components. General for high-current short-circuit fault, the use of cutting method is most significant. If the boot line pipe burning question, be the first to take a leave B-voltage load disconnect. The aim is to disconnect the load to see the fault position is with the power circuit or line circuit, which is the most commonly used circuit cutting method. Another example of a video amplifier voltage 80V-free machine, the real fault for the video amplifier circuit of a capacitor short circuit leading to the power circuit protection, the line does not work. I have also used this method to unplug P904 socket, the line circuit, high pressure is normal. No doubt, as the board put the issue to narrow the scope of failure, until the found the bad parts, troubleshooting.

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