Re: screen flicker: probably not X related

Pippa Reeves is a darn nice person I don't care what anybody says!

Thanks Pippa and Robert too,

I'm going to work through this methodically by process of elimination if I 
have no joy I'll look at a shield maybe.

I'm having visions of a monitor staring/glaring out of Ned Kellyesque headgear 
pondering Joshu's Mu  :^)
>
> What is inside the section of the PC nearest the monitor?....
>
> I would almost make a bet that the wobble effect on the screen is caused by
> the changing magnetic field surrounding one of the PC's fans. These pesky
> little devices have permanent magnets in them, as well as having AC driven
> electromagnets. As the permanent magnet is spinning and the electromagnets
> fed with AC power from the fan's internal electronics both will have
> changing magnetic fields generated.... If the fan is not magnetically
> shielded properly this would make you CRT screen go crazy.
>
> You could try unplugging the fans one at a time and power the computer up
> for a few seconds to see which fan is causing the problem.
>
>
> I very much doubt it is going to be the power supply circuit itself as the
> transformers used in these operate at an extreemly high frequency, and
> usually have a 'shorted turn' type copper shield to keep their magnetic
> field under control. It could be the fan in the power supply though, these
> are usually a 12 Volt DC powered motor as described above.
>
> Be very careful if you decide to open the power supply box up.... there are
> LETHAL voltages present inside that metal box!
>
> Replacing a fan with a better quality unit is not usually an expensive
> exercise.
>
>
> Good Luck,
> Pip
>
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-- 
Cheers,

Rick Miles

Movement stopped is no movement,
and rest set in motion is no rest.

Written on Setting Orange, the 60th of Chaos, 3171 
http://www.members.optusnet.com.au/~rickfrm/