"Sam Goldwasser" wrote in message
...
"Clifton T. Sharp Jr." writes:

Jerry G. wrote:
It would take a very large lightning hit to magnetize or damage a CRT.
The set would have been destroyed first! I think the screen became
magnetized, and should be able to be demagnetized.

Every time I drive past that house, I remember the first time I ran into
a set magnetized by a close lightning strike. It was extremely weird.
The red purity was fine, so were blue and green. But the color picture
looked like severe purity problems. I called the head tech, who told me
to degauss; I was amazed when it fixed the problem.

Yes, the effects of a close lightning strike and nuclear EMP might be very
similar (at least in terms of magnetization of a CRT!).

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I had a strike around eight years ago which took out many, many electronic
devices in my home. Partial list includes vcr (no audio...video fine),
several telephones, one PC and most everything attached to it (even blew out
one of the tweeters on the speakers attached, along with the parallel port
of the printer), another pc which I was able to partially resurrect (blew
out all onboard external ports and HD interface...replaced with ISA/PCI
cards, worked like that for many years until I finally scrapped it).

It literally blew my neighbors telco interface box off the wall of his
house...blew the bark off a stately old oak tree in my back yard (3" strip
running radially from the ground up to about 20'...mostly healed over now,
but I wonder if it will ultimately kill the tree).

The interesting thing is that other many devices survived, including the fax
machine connected to the same line as one of the dead phones, a couple of
other phones, a couple of other vcr's and all of the TV's/monitors in the
house (including the ones connected to the above pc's).

One common thread, however, was that *every* color crt device connected to
a/c mains at the time--whether switched on or not--had severe purity
problems...most of which worked themselves out over the next several days
with normal on/off switching (before most monitors had on-screen
menus/manual degaussing).

So, for the previous poster (not you Sam), it's *very* possible to induce
enough emf into a crt--by way of a lightning strike--to cause the problem
the OP described...without destroying the device.

The symptoms will likely disappear after a few power on/off cycles. If it's
possible to view as is, just wait a few days. Normal usage will eventually
degauss it. If it's particularly severe, you may have to degauss it
manually (if you have a coil). I wouldn't recommend repeated on/off
switching as a degaussing strategy...could stress other components of the
set.

jak