There are two ways to detect the quality of the 7-pin power supply chip: first, the resistance file is detected in the road: the Rx100 ohm file of the multimeter, and the black watch pen is connected to the circuit. A surname Red marker to touch the remaining 6 feet, resistance value in 1K~50K ohm, vice versa 50K ohm above normal; Second, DC voltage file in the road test judgment: use DC500 V, black watch pen " A surname The line, the red marker to connect one of the feet is 300v (Zh 10Ⅴ), one foot is 15V (ZH 2Ⅴ) and the foot pressure 0.5~3Ⅴ is normal, otherwise it is broken. It is easy for the maintenance personnel with practical experience to judge its quality, and those who have no experience need to be careful, and two need to sum up their own experience.
There are many models of seven-pin power supply chips. Use the correct type of chip measuring instrument.