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Post by Casethecorvetteman on Mar 21, 2019 12:32:52 GMT -5
Hi all  Ive now got a red and a green with what looks to be a contamination issue, when looking into the lenses on a black screen there is a glow coming from the bottom of the tube that is off the phosphor surface, and when the set is shut off, the glowing ball appears and shrinks in the center of the tube face. What causes this? One is my genuine Barco red, the best red tube of my bunch, the other is my Eisemann simulation grade green, also the best green of my bunch. |
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Post by robin36mac on Mar 21, 2019 12:35:50 GMT -5
Isn't the ABL line you are seeing ?
Robin
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Post by Casethecorvetteman on Mar 21, 2019 12:56:18 GMT -5
Isn't the ABL line you are seeing ? Robin That is possible, but that doesnt explain the glowing ball on shut down, the blue doesnt do that, although i have one blue that does. |
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Post by robin36mac on Mar 21, 2019 13:27:04 GMT -5
Saw that on the 808 too...
Not anymore since I've swapped the tube for the new set.
Good question.
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Post by Casethecorvetteman on Mar 21, 2019 13:28:45 GMT -5
Yes it wasnt always there on these two tubes either, id love to know why it happens.
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Post by gjaky on Mar 21, 2019 15:07:18 GMT -5
Small contamination in itself is harmless, the more contamination the tube have there is less ability to shut the tube off, or generally control.
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Post by Casethecorvetteman on Mar 21, 2019 22:41:59 GMT -5
Small contamination in itself is harmless, the more contamination the tube have there is less ability to shut the tube off, or generally control. Yeah it doesnt seem to be bad enough to affect black yet, but it wasnt there 6 months ago. I have a blue tube here that needs to have cutoff set about 20 ( 1-99 is range ) and drive was set quite low too. |
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Post by gjaky on Mar 31, 2019 10:29:05 GMT -5
Years ago I came across a poisoned CRT in an oscilloscope, It did quite "fun" lights on the screen, and please note, that a conventional oscilloscope like that is not a raster scanning unit, when there was no trace seen the tube supposed to be cut off...
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Post by stridsvognen on Mar 31, 2019 16:44:32 GMT -5
I have seen that a few times as well. Have had luck removing it by running the tube on a full 100% window 100% IRE level, crank drive up to same level as green if its a blue or red tube, and leavet it like that for multiple hours, if your lucky you burn the contermination away.
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Post by Casethecorvetteman on Apr 2, 2019 9:15:17 GMT -5
I have seen that a few times as well. Have had luck removing it by running the tube on a full 100% window 100% IRE level, crank drive up to same level as green if its a blue or red tube, and leavet it like that for multiple hours, if your lucky you burn the contermination away. I imagine this was Greg's thoughts when he told me to run tube run in cycle for 8 hours. This runs the tubes at full bright for 5 seconds, then full dark for 5 seconds, alternating on-off until you stop it. |
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Post by stridsvognen on Apr 2, 2019 10:43:52 GMT -5
I have seen that a few times as well. Have had luck removing it by running the tube on a full 100% window 100% IRE level, crank drive up to same level as green if its a blue or red tube, and leavet it like that for multiple hours, if your lucky you burn the contermination away. I imagine this was Greg's thoughts when he told me to run tube run in cycle for 8 hours. This runs the tubes at full bright for 5 seconds, then full dark for 5 seconds, alternating on-off until you stop it. Ill think that the initial break in of the phosfor your thinking about, i usually run it in different intensity with a fully maximised raster on the tube, starting off with something like a 30% IRE for some hours, and then 50% for some hours and so on, i slightly overfocus the tubes to get a very even phosfor activation. The flaring however i would just beat the shit out of that tube, run g2 and gain all up, and contrast and brightness as high as possible, and let it sweat, i had a 500 Hour Blue LCP tube douing it, its now perfect, i also had to do it on some Planetarium tubes i have with maybe 1000 hour use at very low contrast, they were looking soft, that disapeared after a good beating at full power, just like a old grandmar car who has been ideling around city, needs some beating to burn the carb off the valves. If it survives great, if not it was junk anyway. |
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Post by Casethecorvetteman on Apr 4, 2019 7:44:51 GMT -5
I imagine this was Greg's thoughts when he told me to run tube run in cycle for 8 hours. This runs the tubes at full bright for 5 seconds, then full dark for 5 seconds, alternating on-off until you stop it. Ill think that the initial break in of the phosfor your thinking about, i usually run it in different intensity with a fully maximised raster on the tube, starting off with something like a 30% IRE for some hours, and then 50% for some hours and so on, i slightly overfocus the tubes to get a very even phosfor activation. The flaring however i would just beat the shit out of that tube, run g2 and gain all up, and contrast and brightness as high as possible, and let it sweat, i had a 500 Hour Blue LCP tube douing it, its now perfect, i also had to do it on some Planetarium tubes i have with maybe 1000 hour use at very low contrast, they were looking soft, that disapeared after a good beating at full power, just like a old grandmar car who has been ideling around city, needs some beating to burn the carb off the valves. If it survives great, if not it was junk anyway. Yes the break in for the tubes is automated on the Barco, not sure how well it works. I dont know how much wear im going to end up with on green after doing that for a few hours, red im not too concerned about! |
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Post by stridsvognen on Apr 4, 2019 7:51:48 GMT -5
Nothing you will notice if you maximise the raster/ image on the tube face, and over focus it some, what you have to loos, its a defective tube, that you might be able to get running perfectly.
And its to beat up the gun not the phosfor so no need to be in focus at all.
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Post by Casethecorvetteman on Apr 4, 2019 21:45:29 GMT -5
Yes i have a memory block thatll work for that, the focus is way off and tube face is near full, i use that for the warmup screen
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