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...the wiring in your house/apartment is not done correctly... >>
Possibly, but sometimes just being in close proximity is enough to cause problems... many years ago I had a client (metal fabricating shop) that claimed his monitor would ?do the hula? about three times a day, no pattern, very random. Changed out the monitor, changed the video card, changed the UPS, still does the hula! Stumped! I had the monitor manufacture, the video card manufacture and even the UPS manufacture checking into this, but as I?m sure you can guess, each of them pointed the finger somewhere else. So one day I just happened to be in his office when the monitor went and ?did the hula!? ? and it really did look like a hula girl doing her moves! - starting from the bottom of the display a left-to-right wave would propagate up to the top, travel time was about 5-10 seconds, monitor would go back to normal until the next hula show.

I was discussing this problem with someone who just happened to be a ham radio operator, and he suggested I barrow a frequency counter (measures radio waves) to see if it?s airborne EMI getting into the monitor... seems he has a similar situation where the radar trace from an adjacent airport was wiping out the video monitors every time it swung around. Long story, short, it turns out that in the next building, which was about 50-feet from the computer as the crow flies, they had a 1,000-hp electric press; every time they fired this thing up it would sent out all kinds of emissions! This thing was so bad that the phones in the shop would drop to static when they started it up. Once we found the source, the fix was easy... there is none! Although I told him he could probably call the FCC and OSHA, I?m sure they?d be interesting in this.

Even additional shielding wouldn?t protect the monitor from these kinds of stray emissions; the majority of which I assume was entering through the glass CRT screen - I don?t think even the screen mask would be enough to protect it, as these frequencies ranged from around 100kHz to 1500MHz with some very, very strong spikes. I assume this is similar to the emissions you get near a lightning strike! Actually there is an easy fix for this today... LCD monitors! However, when this occurred, LCDs weren?t even used in laptops! Come to think of it, they weren?t even called ?laptops? at the time, they were called ?portables!? if you ever had one you?ll know why it?s not a ?laptop!?

Sorry for the long backstory, but I thought you might get a kick out of it.
BTW... I don?t think the ?flickering? you?re experience is related to this, but if you ever come across a monitor that does the hula, check for very large electric motors nearby.
