A masterpiece of keen observation and deductive reasoning, leveraging a good background in physics. That your Sr-VEEP didn't give you a "career wedgie" for making him/her look foolish is a good example of political puckhandling, assuming it was the very same Sr-VEEP that complained about the noise.
On the technology side, although its gotten better over the years through awareness by chip vendors, I swear there were some CMOS chips out there that latched up if you gave them a stern look! I have an old CASIO Data Bank watch I still wear that occasionally latches its beeper ON when I slip off my coat on a dry, cold winter day. Luckily a single button press clears it, otherwise it would be a battery shark.
many years and jobs ago we were temperature testing a load cell application, the in final testing, the strain gages were practially blasted off the beam. Turns out a 200 volt spike on the liner of the temperature chamber when the power cycled. Careful shielding and insulation fixed the problem and it was a very late night.
Cost of line shutdown: tens of thousands?
Cost of replacing 15,000 roller bearings: hundreds of thousands?
The look on the Senior VP's face when told he was the cause of the problem that he is forcing others to resolve by Monday morning: Priceless!
Just two questions - how did the conveyor contractor manage to get grounding springs installed on 14,994 rollers in one Saturday morning, or were just enough rollers grounded to accomplish the demo? And was that the permanent solution (seems that springs would eventually wear through), or did the bearings get changed back to steel?
Nice to see that the author eventually got into management and became a Director of Sales and Marketing. These positions SHOULD be filled by those who have come up through the technical ranks with competence, then problems like that described would not happen.
Good detective work, indeed! And isn't it interesting how those who should stay away instead cause problems by making changes that are certainly not backed up by engineering. It is even more fun when they keep it a secret. It sometimes demonstrates, at least to those who can learn, that engineering design is far more than just drawing straight lines and doing neat lettering.
While I have a dim view of "senior" management, the moral of this story seems to be complexity and compartmentalization.
The Sr. VP only knew the original bearings were noisy, and asked for quieter ones. He had no idea why the original design was spec'd as it was. (And in fairness, why should he? Not his problem.)
The conveyer manufacturer had the specs, but had they been told *why* those particular specs were given? They just filled the customer's order. So when the Sr. VP complained about the noise, they changed the bearings, blissfully unaware it would cause problems. You can argue that someone on their end should have raised a query about it, but hey, a Sr. VP at the customer site changes the specs...
Problems occurred because each group knew only it's particular piece of the puzzle, and no one with an overview was in a position to say "Wait a minute!" when the Sr. VP meddled.
And if the senior VP knew -anything- about electronics, he would have thought twice before changing to insulating bearings on a conveyor for sensitive electronic assemblies.
As above, this is why I call them PSMs....