Symptomatic troubleshooting

Putting all this in the context of power supply design and troubleshooting, the following episode should more clearly illustrate the perils (and signs) of symptomatic troubleshooting. 

We can see a distressing, but not too unfamiliar a pattern emerging here, one wrong move leading to another, to another, and so on. In wise-guy circles this is sometimes known as the Nixon principle, if two wrongs don t make it right, try three. In power, it is called symptomatic troubleshooting. 

In retrospect, what saved the day for me was my willingness to dig deep into theory, fully understand the root cause, and then try to solve it by putting pen to paper. So if you usually find yourself in the lab without a calculator or even pad of paper, you are probably heading down the well-trodden path of symptomatic troubleshooting toward certain disaster. 

---