Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!asuvax!hrc!xroads!wiz
From: wiz@xroads.UUCP (Mike Carter)
Newsgroups: sci.electronics
Subject: Re: funny phosphorus illumination after power to tv has been turned off
Message-ID: <917@xroads.UUCP>
Date: 9 Jan 90 23:43:23 GMT
References: <6805@lindy.Stanford.EDU>
Reply-To: wiz@xroads.UUCP (Mike Carter)
Organization: Crossroads, Phoenix, AZ 85046
Lines: 27

In article <6805@lindy.Stanford.EDU> sorka@ucscb.UCSC.EDU (Alan Waterman) writes:
>
>brightly in multicolored flames. It is quite pretty but I can't seem to
>explain it. Unplugging the set has no effect. It still continues for
>about 10 minutes before dying out. Now this is an active flaming that
>when turning the set off in a dark room where you can see the whole screen]
>lit up faintly.
>
>The only thing that is possible is that the phosphorus is being bombarded
>by electrons, but how can this be if the power is turned off? Is the CRT
>drawing on capacitors or something?

Someone once mentioned a similiar effect on a TV set quite a number of years
ago . The explanation given was never proven, but it sounded feasable
enough at the time.
It was said that since all tubes store HV after the power is turned off,
sometimes if a bleeder resistor is bad or if there is a nick or cut on
any of the HV parts that discharging through ionization can cause electrons
to spin off and bombard the screen....but in your case I'm stumped because
this explanation would mean that the bombardment would have to be focused
or there would have to be a scratched off area of the coating of the outside
part of the tube. Well, since this is being written 200 messages
down from the top of the heap, I'm sure someone else knows what it
is. Sounds interesting tho.
 	
		-Mike    N7GYX
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