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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Thu Feb 14, 2008 5:50 pm Post subject: More tubes under pressure |
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I am getting some NOS MArquee 8" tubes in, but the raw tubes only. So I cut some burned tubes out of the housings for the first time.
EACH tube had enough pressure in them to eject the fluid before the screw was undone fully. One actually shot the screw up a couple of inches, I could feel the pressure as I was unscrewing the screw.
HOWEVER.. I've never read of an imploding 8" MArquee tube here or at avs. Ever.
So I wonder if the broken NEC tubes and the odd imploded 9" tubes aren't just due to glass fatique, and have nothing to do with glycol pressure? I know the NEC tubes are thinner than the Marquee ones, but it stands to reason that the P19 tubes are slightly thicker than the 8" ones. THe 8" MArquee housings have no 'give' to their mounting, whereas the 9" tubes do in all sets, as even the Ampros have rubber bellows that expand with water absorption.
Just thinking aloud here. I'm not saying an air bubble isn't a good idea in any LC or non LC tube, I'm just wondering if it's really preventing tube implosion.
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Thu Feb 14, 2008 6:08 pm Post subject: Re: More tubes under pressure |
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| Curt Palme wrote: | | I am getting some NOS MArquee 8" tubes in, but the raw tubes only. So I cut some burned tubes out of the housings for the first time. |
Looks like you have been shopping at Terry's tube store 
Cutting those old tubes is a lot of fun but I managed to do it last night without breaking the old tube or slicing myslef . 
I think the pressure inside really depends on the age of the tube, the older the tube the more moisture it will have absorbed. The one I popped the screw on last nigth barely had a dribble, and that was at 5K feet atlitude. Others have shot out quite the stream, so it depends.
Last edited by draganm on Thu Feb 14, 2008 8:41 pm; edited 1 time in total
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nuttall_chris
Joined: 08 Mar 2006
Posts: 832
Location: Ottawa, Ontario, Canada
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| Posted: Thu Feb 14, 2008 6:08 pm Post subject: |
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I've also wondered about this. I have a hard time believing that the tube would implode before the bellows would rupture on the LC units.
Chris
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Thu Feb 14, 2008 6:22 pm Post subject: |
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Guys!
Don't forget, the tube envelope has a vacuum in it so it is the fluid pressure plus near 15 psi on the glass, so the glass is inherently stressed more than the bellows.
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gregstv
Joined: 27 Aug 2007
Posts: 628
Location: Australia
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| Posted: Thu Feb 14, 2008 10:06 pm Post subject: |
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Hi
I have found that the glycol expands over time.I repair a lot of samsung rear pros with leaky tubes.The coolant
expands and lifts the lc assy of the tube.To fix i remove about 10 to 15ml of coolant and reseale the tube.
So may be a small amount of coolant should be removed from all tubes that have built up pressure.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Fri Feb 15, 2008 9:32 am Post subject: |
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Those tubes can't implode because bellows bleed like sieve. 
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Fujifrontier
Joined: 20 Oct 2007
Posts: 354
Location: San Antonio, Texas
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| Posted: Fri Feb 15, 2008 11:48 pm Post subject: |
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hopefully not all over boards...
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fcoutinho
Joined: 19 Oct 2008
Posts: 5
Location: Brasil
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| Posted: Wed Nov 12, 2008 3:04 am Post subject: |
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| Fujifrontier wrote: | | hopefully not all over boards... |
What if the glass chamber of the glycol is a normal glass that can be bought in any store? (My broken when doing the cleaning of fungi)
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Filipe Coutinho
from Brasil
BarcoVision 708
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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fcoutinho
Joined: 19 Oct 2008
Posts: 5
Location: Brasil
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| Posted: Wed Nov 12, 2008 3:26 am Post subject: |
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| Nashou66 wrote: | | what you can do is look for a cheap burtn tube and remove that glass and replace it. |
I'm trying to do this, but I do not think any tube to remove the glass.
_________________
Filipe Coutinho
from Brasil
BarcoVision 708
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AnalogRocks
Forum Moderator
Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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| Posted: Wed Nov 12, 2008 5:30 am Post subject: |
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| fcoutinho wrote: | | Nashou66 wrote: | | what you can do is look for a cheap burtn tube and remove that glass and replace it. |
I'm trying to do this, but I do not think any tube to remove the glass. |
fcoutinho, you DO NOT need to post the same question 13 times. Since you got your answer here I'll remove the other post's.
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fcoutinho, você não precisa de afixar a mesma pergunta 13 vezes. Desde que você começ sua resposta aqui I' o ll remove o outro post' s.
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fcoutinho
Joined: 19 Oct 2008
Posts: 5
Location: Brasil
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| Posted: Wed Nov 12, 2008 9:43 am Post subject: |
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Sorry!
I thought each of the topics was independent of the other and that the question would only be seen by people who posted the topic.
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Filipe Coutinho
from Brasil
BarcoVision 708
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