Never heard of this

It's very common, the shadow mask has become magnetized by the intense magnetic field created by the nearby lightning strike. Normally the internal degaussing coil is enough to fix it and the rainbows will go away on their own after turning the set on from cold a few times. If it persists then you'll have to use an external degaussing coil or bulk tape eraser to do the job.

Take the wall plug out before you go to bed, and the next morning plug it in and everything should be just fine :-)

(a special resistor inside has to cool down...)

It's a PTC thermister, and no need to unplug it, just turn the set off and let it cool for a half hour or so.

don't worry, it will go away!, just turn off the tv and let it cool down and then turn it back on. do this a few times so that the coil can degauss the screen that is around the tube..

I was working with 3M one time on a magnetic traffic marking tape. They really got a lot of magnetic material into the tape. One of the engineers was demonstrating by running a piece around a computer (CRT) screen, and permanently hosed up the screen. He had to go out and buy a demagnetizer/degausser from Radio Shack to fix the guy's monitor :-)

There is a limit to the strength of the built-in degaussers, though. It may indeed take an outboard degausser if the mask was magnetized strongly enough.

the electric current in the strike causes a magnetic pulse which magnetises the iron/steel parts in the monitors, the magnetic field caused by these parts distorts the piicture and particularly the colours.

as you have seen it does heal slowly, also turning the device off and on or activating the "degauss" feature will usually fix this problem. in bad cases it may need to be repeated a few times.

Bye. Jasen

The weirdest one I ever saw had perfect purity -- red OR green OR blue OR monochrome -- but had the funkiest colors you could imagine. I puzzled over that set for half an hour before calling in to the chief tech for help. He insisted on my degaussing it despite the perfect purity, and of course that fixed it. It was only then that I realized there was a storm the previous night, and asked the lady of the house if lightning had hit nearby; she pointed to a blackened spot on the concrete not fifty feet from the house and claimed a direct hit there.