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Discussion Starter · #1 ·
Hi there.


I have a BG808 that I'm very pleased with. However, when I press

pause, there's light in the tubes. No image, but a glowing light coming

from the bottom of the tubes(table-mounted). What can cause this?


Should I begin to cry now, or wait?


Nicholas
 

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Sort of a mini Aurora Borialis in each tube...


My opinion since I've seen it so many times is that it's normal. If you look into the tubes as you turn the projector on you will see this right at first as well. What I don't recall is if this is more of a MEC tube phenomena? I'm not sure that I've seen it with Sony tubes.


Wait a second... okay. I just spooled up a BG808 in the other room and got the Aurora Barco going in pause mode myself...


Mark
 

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I would think you're seeing the heater filament glowing. In pause (or standby) mode my understanding is that it's just the HT that's not being fed to the CRTs.


Someone please correct me if I'm wrong.


Andy.
 

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Discussion Starter · #4 ·
But it is still safe to have it on pause? It won't burn phosphor?


Please be sure if you answer!:)


Nicholas
 

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The filament is basically an incandescent light-bulb such as you would have in a battery-operated torch. The voltage is set so that the filament heats up enough so that it glows orange, but not enough so that it glows white-hot (as in a normal bulb).

In operational mode a very high voltage is applied to a 'grid' part way up the tube. This grid strips electrons from the filament and they move up the tube neck. Magnets then align the electrons into a 'beam' as they move up the CRT, eventually striking the phosphor. The excited electron disperses its energy as light.

If the grid is not charged (ie HT is switched off) the electrons won't be stripped off the filament, and thus nothing will excite the phosphor.


So - your phosphor is quite safe in standby/pause mode.


Andy.
 

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It may be possible that the G2 settings are up a bit if some of the rasetr is illuminated. If the raseter or any part is lit, even at less then full brightness it sure is possibe to burn that are of the phosphers. Its gonna take a hell of a lot longer but Im sure it is possible.
 

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It doesn't look like something being scanned onto the tube face in the raster. Its like a glow like Nich said. Sort of a glowing light off the face of the tube and the glow is that tube's color. Very very faint in regular room light and more obvious in the dark. I've tried to take a picture on a BG808 but the picture seems to have enhanced it to appear worse than it may be.
 

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Could be the AKB. Certainly not an issue.


Marc
 

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Discussion Starter · #9 ·
Thanks for your help. Regarding the pictures, I have a more 'beautiful'

'dreamy' glow:) that extends a bit up the tube...however, the raster

is not lit up.


Nich
 
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