How to quickly judge the power chip is good or bad! Personal experience, do not ask students to pat everywhere!
When a voltage does not come out, of course, it is related to the power chip, whether the chip is bad or the surrounding components are bad, if the mood is good, a foot by foot measurement may be more accurate, usually I want to be lazy.
one. The first test inductance resistance value is normal, and the upper and lower tubes are normal without breakdown.
two. Measure the voltage. There is power supply, excitation, ON. Normal three. If the G-pole voltage of the upper and lower tubes is 0, the chip is faulty. When the upper tube G is extremely 0 and the lower tube G is extremely 5V, the chip is generally normal, and the large capacitor must be suspected first, then the small capacitor, and then the resistance.