How to solve the actual running problem of most circuit boards?
Multimeter; is the main tool for running, tweezers are often used to locate the position of the element pins, and magnifying glasses are used two carefully observed the wiring interconnections and surface models of the components
In general, there are four basic methods of running, namely, "observation method", "trial method", "ground resistance value run line method" and "element package size discrimination method".
1.The method of observation is to directly and clearly discover the straight through relationship between the components through the naked eye. The observed object is the visible wiring and the pin of the component. Because the total number of ATX power components is much less than other circuit boards, such as motherboards, and most of them are single - layer cabling (up to two - layer cabling), the running process is very intuitive, even if you simply use the observation method to meet the actual needs of the running line. It is only necessary to remove a number of components (such as transformers, heatsinks, etc.) By using soldering iron and soldering devices when the wiring ice obscured by the element.
2.The trial method is to fix one of the multimeter’s pen to a certain point, and the other two, find a way to connect with a fixed-point town trying to contact a plurality of moving points, and by repeatedly exploring whether it is straight through or not. The advantage of the exploratory method is simple, but its disadvantages are also very obvious, even if there is a pass-through point in the scope of the test, it may still need to be tried many times to find the pass-through point.
In the physical graph, all numbers are ground resistance values measured with a multimeter; that the element pin (regardless of first of all). For example, the earth resistance values of points a, b and c are all 767. It is speculative that the three test points are straight through, and then uses a multimeter; two confirm whether they are really straight through or not. The result is indeed a straight through, and then it is connected with a broken line. It is not hard to campaign that as long as the process is repeated (looking for a value close enough to the earth resistance, the multimeter; verifies whether it is straight through), the vast majority of the interconnection of the board can be traced. Combined with the observation method, the running line problem of ATX power supply can be solved almost completely.
3.We should pay enough attention to the "run of the earth resistance method". The component package size discrimination method is a more advanced method of running line, only after relatively familiar with the component knowledge and circuit knowledge, it is possible to use this method. This method can have an unexpected effect to some point. The core of element package size discrimination method includes two parts: one is to master the type, package size and parameters of all the components in the circuit; the other is to master the specific applications of the components in the circuit. It is an important auxiliary running method in addition to the method of resistance to the ground. This is also a better way to run the line for skilled people than for beginners.
4.The component package size discrimination method is actually an extension of the observation method. In observation, the object of observation is visible wiring. In component encapsulation discrimination, the object being observed is a possible logical relationship between multiple components.
Flexible use of the above four methods can effectively solve the actual running problem of most circuit boards, including but not limited to the ATX power supply.