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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Sat Jun 12, 2010 11:46 pm Post subject: New stock Marquee 8" 8xxx tube imperfections |
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I've never had a pj with new tubes before but recently gathered up a full set from 2 different members. (Thanks Ben!  Thanks Paul! )
With the lenses off and up close and personal to mark the centers I just noticed the green and red both have a very tiny black dot imperfection in the phosphor. The green is outside the raster but it's right in the image area on the red. The haloing will probably make this a non issue (AC 8500) but it begs the question...Is this normal for new tubes? (and I just never noticed on used tubes with some wear.)
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Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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cmjohnson
Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s
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| Posted: Sun Jun 13, 2010 12:00 am Post subject: |
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It's not unheard-of. But you don't normally find tubes with any such flaws that have already been installed in a projector as they get rejected by quality control before making it into a projector at the factory.
VDC, for example, will reject a brand new P19LCP for a barely visible imperfection in the phosphor even if that imperfection is so far off
toward the edge of the glass that there's no way it will ever be in the projected image.
New tubes from the manufacturer's outlet which have NOT been through that quality control process can be expected to occasionally
have some little imperfections like you describe. This is actually a very compelling reason to buy your tubes from VDC. If you buy
from them, you will get tubes that are inspected and guaranteed free of flaws when you get them.
A missing spot that's that small on a red tube will probably be virtually impossible to see in normal viewing. On a full white screen it
would show as a cyan spot. On a full red screen you might miss the black spot.
Go with it. You'll probably never notice.
CJ
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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Sun Jun 13, 2010 12:29 am Post subject: |
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So what does VDC do with these 'reject' tubes? Can they salvage anything out of them? I sure wish we could buy them. I'd take a set of HiRez tubes with out of image imperfections!! Beats scrapping them.
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Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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cmjohnson
Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s
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| Posted: Sun Jun 13, 2010 1:14 am Post subject: |
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They get sent back to the manufacturer for full credit. There's probably no point in trying to pursue them as the cost of a defective tube
is going to be the same as the cost of a perfect one.
I was thinking about that angle, too, until I learned that part.
The catch is that today, the manufacturer is a subsidiary of VDC and VDC isn't easy to buy scrap and surplus from. This I can attest to for a fact.
CJ
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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Sun Jun 13, 2010 3:32 am Post subject: |
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| cmjohnson wrote: | They get sent back to the manufacturer for full credit. There's probably no point in trying to pursue them as the cost of a defective tube
is going to be the same as the cost of a perfect one.
I was thinking about that angle, too, until I learned that part.
The catch is that today, the manufacturer is a subsidiary of VDC and VDC isn't easy to buy scrap and surplus from. This I can attest to for a fact.
CJ |
I'm still curious as all hell how much 'junk' (to VDC and their partners) goes to recycling when these items would be perfectly OK for our use. Hell, let's face it. Not many of us can spring for new tubes so they'd never get our money anyway.(or would spend the cash...it IS just a hobby after all...<ducking>) Win Win for all involved and no special disposal costs.
Hey CJ, on an unrelated note; what all is involved to convert an AC to an LC?...'just' bellows and housings...perhaps the top and bottom tube pivot plates?
_________________
Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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cmjohnson
Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s
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| Posted: Sun Jun 13, 2010 3:38 am Post subject: |
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Bellows, housings, mouting plate On LC Marquees, there is only one mounting plate, not a top and bottom. Only a bottom plate.
Any small machine shop could easily make new plates for you if they knew the dimensions and other relevant data. It's just one plate
with a few circular arc slots cut in it and three dowel pins and a couple of bolt holes.
I think VDC should get the idea that even those slightly defective tubes are quite sellable in the home theater market. Not for as much as a perfect tube goes for, but would they rather turn that tube with one blemish into 400 bucks cash or a broken lump of glass in a dumpster that isn't worth a dollar at the recycler's?
I'm actually working on trying to make THAT deal happen. Please don't get involved. If they have multiple people asking about the same thing, they won't even bother to deal with any of them. If I can make any headway I'll post about it when the time comes,
maybe try to set up a group purchase or something.
I've already got this ball rolling so please stay out of the way. That goes for everybody. If you get involved it'll kill the deal.
CJ
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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Sun Jun 13, 2010 4:28 am Post subject: |
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| cmjohnson wrote: | Bellows, housings, mouting plate On LC Marquees, there is only one mounting plate, not a top and bottom. Only a bottom plate.
Any small machine shop could easily make new plates for you if they knew the dimensions and other relevant data. It's just one plate
with a few circular arc slots cut in it and three dowel pins and a couple of bolt holes.
I think VDC should get the idea that even those slightly defective tubes are quite sellable in the home theater market. Not for as much as a perfect tube goes for, but would they rather turn that tube with one blemish into 400 bucks cash or a broken lump of glass in a dumpster that isn't worth a dollar at the recycler's?
I'm actually working on trying to make THAT deal happen. Please don't get involved. If they have multiple people asking about the same thing, they won't even bother to deal with any of them. If I can make any headway I'll post about it when the time comes,
maybe try to set up a group purchase or something.
I've already got this ball rolling so please stay out of the way. That goes for everybody. If you get involved it'll kill the deal.
CJ |
If I had a template I could make one from stainless at work when I get back.
No problem man. I have a full plate as it is just trying to healthy-up and get back to work.
Thanks CJ. When I get around to converting it (and have the $$$) I'll put out a call for parts.
_________________
Greg
"Is it ignorance or apathy? Hey, I don't know and I don't care!" --Jimmy Buffett
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cmjohnson
Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s
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| Posted: Sun Jun 13, 2010 5:02 am Post subject: |
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I can give you dimensional information pretty easily. It's not hard to just describe the plate. I can make a few measurements and that's all that's needed.
An aluminum plate about 3 inches wide, a quarter inch thick, and about 30 inches long (or somewhat shorter) is what you start with.
One edge needs to be milled a bit thinner to fit under the lip in the chassis.
On an LC machine, no arc cuts need to be made in the mounting plate as they're made in the LC housing flange instead.
CJ
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