Could someone please settle an argument for me. My brother told me I would damage my plasma tv set by placing speakers which are not magnetically shielded next to it. I thought that only applied to CRT tv sets & not plasma.

I'd be grateful for any advice, as my plasma is my pride & joy and I don't want to risk damaging it.

You are correct, plasma displays are not affected, neither are LCD or RPTV's (DLP).

I understand it has something to do with the magnets in the CRT that are used to aim the electron, a magnetic field deflects the electron beam in its path to the phosphors, the result is staining/coloured tinge to the edges of the screen where the speaker/magnet has been placed.

No magnets are found in Plasma/LCD/RPTV (DLP)

quite correct but to be pedantic i think it is the proximity of the unshielded magnet in the speaker which causes a disturbance to the field coils around the electron gun, this in turn causes the unwanted deflection to the beam and the effect previously described, but hey its old technology so who cares ! long live plasma (and lcd)

To be even more pedantic!

That's incorrect, the electron beam in a CRT is deflected magnetically, if you have a magnet near the CRT neck it will deflect the beam before it enters the scan coils. Once it's entered the scan coils their powerful magnetic field is probably going to over ride any external magnatic field.

But far more of an effect is caused by magnetising the shadow mask, upsetting the purity, and this is what unshielded speakers cause - nothing to do with deflecting the electron beam. Which is why moving the speaker away often doesn't cure the fault - because it's permanently magnetised the shadow mask. TV's have a deguass circuit to correct it, but in severe cases an external deguassing coil is required.

ok fellow pedant i went and looked it up rather than guess !
Apparently in even more extreme circumstances very strong magnets such as the now popular neodymium iron boron, or NIB magnets, can actually deform (and likely, permanently bend) the shadow mask. This will create an area of impure color rendition on the screen and if the shadow mask has been bent, such damage usually can't be repaired even with external de gaussing

does all this de gaussing affect the enviroment?

I've never seen or heard of that ever happening, but I have repaired a fair number of lightning damaged TV's over the years to then find out the shadowmask has been permanently damaged by the lightning!.

If the shadowmask has been deformed by a VERY strong magnetic field, then presumably a very strong deguassing field would correct it? - but presumably no one makes such a device?.

didn't they have one in the Philadelphia experiment, although that disapeared a battleship, so it logically follows that would easily disapear the telly ? so not much use then

It must upset the pigeons navigation skills - "Nearly home, bugger, where's that magnetic field gone".

sounds as if you cant find your way home from the pub!