Sony trinitron wega response to Wiz

Thank you for your solution.

I did look under frequently asked questions at the Sony.com.
It suggested that it may be due to some sort of magnetic field due to stereo speakers and stereo location.
The speakers have always been where they are, so I couldn't understand what that would happen now - after all this time. But I decided that it couldn't hurt to try their first recommendation - which was to unplug the entire tv system for 20 minutes and then restart it.
I'm a lucky girl - that worked!

Thanks for your help!