We had a user with a constant 60Hz flicker on his crt. Wasn't a nearby fan. Swapping monitors didn't fix it. The same monitor worked fine elsewhere. Changing settings just changed the patterns.
I was totally stumped until I realized that the ginormous breaker panel that fed half a factory office floor was directly on the other side of the wall. The user simply rearranged his desk with the monitor on the opposite side and all was well.
Biting the hand that feeds IT
