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Thread ID: 30450	2003-02-20 00:18:00	Shimmering monitor picture	Shooter (3119)	Press F1

Post ID	Timestamp	Content	User
122483	2005-04-05 05:43:00	I work in a cube farm and it gets really hot. The problem is that a desktop fan (even a small one) is bad for causing a shimmer (any electric motor is (magnet boosted by copper coil)). Anyway, depending on the strength of the magnetic feild, the effect can happen from quite a distance. Keeping myself cool affected three monitors Any magnet will do it, not just electric sources.	apparition (3207)
122484	2005-04-05 13:17:00	Realistically you cannot shield a CRT monitor against it, but moving the monitor to face in a different direction may mitigate some of the effect. Well GF, another rare disagreement! You most certainly can shield monitors against external fields, and I have done so for a number of commercial clients using imported custom built shields. I have shielded monitors up to 21" with great success, even in high field situations like power stations. My orignal advice at the head of this elderly thread stands though, and it is not "all magnets" that cause shimmer-type interference, it is only electrically powered sources that do this. Static magnetic fields just cause discolouration. Increasing the refesh rate is not a real answer either because although the interference appears to go away, it is still present but tracking faster than the concious eye can see. Unfortunately the 'subliminal eye' still sees it as a blurry image, causing fatigue and headaches for users. Some users can get away with it though if their eyes have lower than average response time. The best answer is LCD screens but they don't always suit users of larger CRTs, espcially in the graphics field. Cheers Billy 8-{)	Billy T (70)
122485	2005-04-05 21:43:00	The "realistically" qualifier suggests that perhaps they cannot "realistically" afford your fee for doing it...?	godfather (25)
122486	2005-04-05 22:04:00	The "realistically" qualifier suggests that perhaps they cannot "realistically" afford your fee for doing it...? Point taken GF :horrified , but it is not all that expensive and significantly less than the cost of conversion to large screen LCD. It is more of a sales transaction than a consultancy issue. Certainly enough users found it an economic solution to make it worthwhile holding stocks here in NZ. The biggest problems are the bulk of the shield, and the need to customise the shield dimensions to minimise that bulk for 20" and 21" monitors. All others fit in standard sizes. Cheers Billy 8-{)	Billy T (70)
122487	2005-08-18 05:23:00	You most certainly can shield monitors against external fields, and I have done so for a number of commercial clients using imported custom built shields. I have shielded monitors up to 21" with great success, even in high field situations like power stations. I have large speakers close to a crt monitor in a tight space, so moving them away is not really an option. Is there a cheap way to sheild them? What can be used?	communal (3208)
122488	2005-08-18 05:51:00	Well, you can shield them but it will not be pretty. In essence you will need some fairly thick steel, 1mm would be about right, and that will have to cover the side of each speaker that is facing the monitor and go about 50-75 mm past the back edge of the speaker enclosure. It can bend around the back if you want to try that. You can shield inside speaker cabinets, and if they heve exposed ferrite magnets I have seen good results with a semi-circle of heavy gauge metal around the side of the magnet closest to the speaker. Forget aluminium foil or any other folk-lore remedies, ferrous metal and a fair amount of it is the only effective shielding, unless you go to exotics like mu-metal that will cost you an arm and a leg. You could try doing several degausses of your monitor as well, that may reduce the problem slightly, but it is not a cure. Cheers Billy 8-{)	Billy T (70)
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