Same colour problem on two sets - please advise!

Recently, my 12-year old Sony TV developed a problem in which the picture often appeared to have a greenish tinge. This seemed to affect mainly indoor scenes, where the walls of rooms that should have looked a neutral light brown or grey colour acquired a pale green or green-yellow tinge. It was present on all sources - DVD (both PAL and NTSC), VHS and broadcasts.

As the set was old and already had a few other minor problems, I've now invested in the Toshiba 32ZD26. But I'm now noticing the same greenish tinge on this set as well. So far I've noticed it most on a PAL DVD but it's also apparent on broadcasts as well in certain shots. This leads me to believe that the cause might be something environmental in the room. I have a Dolby Digital 5-speaker set-up with large floor-standing KEF front speakers positioned about 18 inches away from the TV, and a fairly large centre speaker (also KEF) housed directly under the TV. The speakers are supposed to be magnetically shielded, but I'm wondering whether, perhaps, the centre speaker's shielding has broken down somehow. Is this possible, and could it be the explanation for the problem? Or can anyone suggest other possible causes? I'm very puzzled and also quite concerned, as this is a new TV. Any suggestions will be gratefully received.

 

Toshiba 32ZD26 has blue mute, if you select BBC1 for instance and unplug the aerial, or select a channel which is blank, number 55 or whatever, the whole screen will be a solid blue.
If De-gaussing is needed the blue screen will have coloured patches usually red, yellow or green, often in the corners. If it's a perfect solid blue your speakers are not to blame.
If De-gaussing is required your supplying dealer will call around under warranty so no charge.
Magnetically shielded speakers have a second magnet which cancels out the magnetic radiation of the first magnet, it cannot " fail " as such. The large floor standing speakers are magnetically shielded too ? If not a distance of 18 inches can still affect your CRT. Move them further away if possible after de-gaussing.