At my first job after college my boss/mentor had spent many years in medical electronics before moving to our oceanographic firm. One time when I was upset that management wouldn't listen to reason he told me that as an engineer many times you will see disaster coming, management won't listen to you, and people will die. You just have to make sure you have done your best and get over it.
I was once checking out a CCFL inverter and after some tests, I forgot to turn off the machine. So, I grabbed the inverter, because I wanted to disconnect it, and I suddenly I sensed a BBQ-like smell......which turned out to be my burning thumb in touching the HV connector on the PCA.
It didn't hurt at all, but it left a funny hole in my finger which took almost 2 weeks to disappear.
Sorry, no pics...
Well... You've got the case of the commercial airplane that crashed because the pilot thought he had x-kg of fuel, while they actually loaded x-lbs... Right in the middle of the flight, the engines turned off...
I wonder why such marvelous machines wouldn't include one of those simple fuel level indicators, at least to check fuel level while on ground (surely, it won't work during acrobatic maneuvers nor high-pitch climbs).
Many years ago, a young technician was working on a Racal SSB transmitter (all valve). He had an original set of spares. He decided to replace the main HT electrolytic capacitor, a rather large device, screw terminals etc. 450V rating. Turned the power on and the capacitor exploded with sufficient force as to coat the ceiling. Needless to say that the capacitor had never been powered up since manufacture and was in dire need of re-forming. It is a wonder that the floor under the technician was not coated as well.
Stuxnet. We all agree it was sabotage, but the centrifuge designers were "leading with their chins." Even without the possibility of malice, any control system, especially one with computer control, should have an independent over-range safety shutoff. In this case one needs a completely independent tachometer that would stop the centrifuge if the speed exceeded a preset limit.
Waaaay back when i was a teenager & messing around with electronics in our basement, i built a nifty little box. It had an AC plug on one end, a switch and a fuse (the screw-in type) on the box, and two big colored alligator clips coming out of it. Yep - i could hook 110 to wherever i chose, & switch it on and off "safely!" When I think of the number of times that i could have fried myself in that little basement room with that little box of torture, it just makes me amazed that i'm still alive! To top it off, my dad was an electrician - yes, he taught me well, but an enthusiastic teenager playing with electricity is not well-known for caution.
At Norway's only technical university 30+ years ago we did not chose Telecom vs Computers vs Power Distibution until we had a stab at all for a few years. After some "interesting" experiments in the High Voltage lab I decided 5V was enough for me.
However how was I to know that 5V@300A PSUs as needed for some quite advanced telecom/computing stuff in as needed by the industry ca 1980 also make for an interesting day in the lab? ECL and Schottky - not LS gets hot as well.
So 5V@30A and 74LS only was then my new limit for what I would touch - until I found out about what happens to tantal caps when connected the strong way rund! I have been an advocate of low power CMOS and ceramic caps ever after!
The real sad part of the Hubble screw up is that guys from JPL visited Perkin Elmer to check the mirror with the old fashioned "knife edge" test, but PE wouldn't let them into the lab because the facility was also used for secret spy satellite optics. PE assured then that their sexy computerized testing was far better anyway.
The fix was not to replace the screwed up primary mirror--it was too big. The solution was to map out the aberrations and grind a secondary mirror to cancel them out.
The interesting question about the Hyatt Regency disaster is the one that wasn't asked. People debated the diameter and thread pitch of the supporting rods, and whether they should have been lapped or continuous. What nobody asked is why anyone would build an indoor foot bridge out of concrete in the first place. Isn't that what wood is for? Light, strong, and fatigue resistant.
Blog Make a Frequency Plan Tom Burke 17 comments When designing a printed circuit board, you should develop a frequency plan, something that can be easily overlooked. A frequency plan should be one of your first steps ...