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FEATURED ENGINEER What was the trickiest bug you ever fixed? Well, this one comes from my second job as a CNC technician. It was this medium-size CNC. The customer reported that when he pushed the power button, the NUM controller would sometimes fail. He would then have to turn the machine off and turn it back on again several times until the power button would work normally. After several hours (days) I discovered that the problem was a bad pin connection from the CPU chip of the NUM controller. The reason for the power button failure was the funniest and most interesting part: the power button would arm a large power relay. The relay was mounted onto the same surface as the NUM controller at the back of the switching cabinet. Being large enough, the relay caused vibrations when armed. These vibrations sometimes would vibrate the CPU chip inside the NUM controller for just an instance, long enough though for the controller to raise several errors. I liked this repair so much that I uploaded it to my website.

Do you have any experiential stories you’d like to share? I had a very close contact with the 220V when I was a child. I was making this antenna that required a 220V supply up on the roof of my house. The antenna was supposed to receive strange signals—I never found out what a “strange signal” was, but I could definitely hear the hum in some bands of a toy walkie-talkie that I had. Maybe aliens? Who knows. Anyway, it seems that as I was pulling the wire it got scratched somewhere. I accidentally grabbed the wire from this scratch. My right thumb touched the copper and 220V went right through me down to the wet concrete. I can still remember each and every second while I was stuck there. My hand closed and I held the wire even tighter. The shock lasted for several seconds. I was twice a lucky guy to live – first because it was my right hand and not the left hand. And second, because my thumb got so severely burned that turned into a big blister. And so here I am! For the next 3 days it was impossible to move my right side due to this terrible pain, but slowly I recovered. After 20

“Concern each failure as a valuable lesson, for if you don’t find out how something will work, you will definitely find out how it doesn’t.” years, I still have the mark from the blister on my right thumb only to remind me how dangerous those strange signals are...

Is there anything you’d like to say to young people to encourage them to pursue electronics? Electronics can be a very nice hobby with a bright future. As long as one likes electronics I definitely encourage them to go on with that passion. Start with small steps and try not to get disappointed from the early and inevitable failures. Concern each failure as a valuable lesson, for if you don’t find out how something will work, you will definitely find out how it doesn’t. Learn how to learn at a personal level. Each one has a different way to learn—discover yours. Share your knowledge with friends and on the Internet. Read math, study math, learn your lesson by heart. There is more than numbers behind the numbers. But most of all, study the original text of the Euclidean Geometry. Discover the methodology and the logical steps of a harnessed and disciplined mind.

What challenges do you foresee in our industry? Oddly enough the greatest challenge that I foresee is how humans will handle the not-so-distant future industrial innovations and technologies. Every day, we manage to harness more and more energy which can either be creative or destructive. There will be this time (maybe I will be a spectator in my 70s+) that we will face this situation. We need to either radically change our behavior and ethics, or we self-destruct.

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Modern Printed Circuits: Sierra Circuits