Comment by cookiengineer
Comment by cookiengineer 3 days ago
A friend told me once that his mouse stops working when someone is using the microwave. His room was on the backside of the kitchen.
When I took a look at it, it turned out that his (proprietary) wireless USB adapter for the mouse was very close to the band of the noise of the microwave. The microwave was also not properly grounded and shared a circuit breaker with his room, as apparently the kitchen was formerly larger and then split into two rooms by the landlord.
That was quite funny seeing that problem happen in action, he was always joking about a ghost in the machine, and I was joking about him being radiated by his microwave.
The cool part is years later in University one of my commilitones told me that his mouse stops working when the fridge turns on. The first thing that I checked was whether or not there's noise on the power circuit, et voila, easily fixed.
Noise on powerlines is annoying, very frequently present and sometimes dangerous.
Long ago there was this case of a factory that pressed desks out of steel sheets. Their main press (an absolute monster) had taken someone's arm off and they couldn't find the cause. It turned out that near the roof there was an air conditioning unit that that had a flaky relay in it that drew a gigantic spark on disconnecting, enough to upset the latch that controlled the safety interlock on the press, causing the press to move by itself.
It took quite a while to find it.