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stridsvognen
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| Posted: Sat May 11, 2013 2:00 pm Post subject: Marquee 8500AC ANSI contrtast improvement ? |
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I just got a old Marquee 8500AC projector, and was wondering if its possible to improve the ansi contrast by masking the tube face not used, with some veltex, like used on screen frames, and also add that to all the bare aluminium reflecting light betwen the lenses and tubes.
There is also quite a lot of leak light crosing from tube to tube, would it be ok to put a plate or some sort of materiel there to block leak light from crosing tubes.?
Im new to the AC model, so i have no idea how hot the glass in front of the tube gets, and dont want to isolate it if its important to cooling, but i cant feel any heat from the aluminium frame after hours of use.
Im sure there is some old threads about this, but i dident find any.
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sat May 11, 2013 2:08 pm Post subject: |
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Hello
The real problem is reflection from the first lens element across the air gap back onto the tube face, common to all AC lens setups. In an LC setup, the glycol IS the first lens element and there is no air gap.
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stridsvognen
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| Posted: Sat May 11, 2013 2:11 pm Post subject: |
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I follow that Tim, but is there no effect of removing the light reflections bounching around in there, and blanking the glass/ tube face not used in a 16-9 setup.?
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sat May 11, 2013 2:14 pm Post subject: |
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Hello
There could be benefits, but that is a lot of work in experimenting; why not just swap in nine inch tubes?
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stridsvognen
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| Posted: Sat May 11, 2013 2:22 pm Post subject: |
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| Tim in Phoenix wrote: | Hello
There could be benefits, but that is a lot of work in experimenting; why not just swap in nine inch tubes?
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I have 2 X 9500LC machines, this will be my test machine for new boards mods and so.
So just for experimenting, and the light bounching around in there and leaking all over looked a bit like someone dident care, so just curious if was a place to do a cheep mod on a AC projector.
Im quite positive about how it performs with resolving 1080P and the light output.
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fragzero
Joined: 30 Aug 2012
Posts: 344
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| Posted: Sat May 11, 2013 7:02 pm Post subject: |
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I have read about this practice. I have thought about doing the same (spraypainting the mounts black + taping of tube.
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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stridsvognen
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| Posted: Sat May 11, 2013 9:26 pm Post subject: |
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The halo thing im sure cant be changed, but dont it help a bit on the washed out image with high IRE scenes.?
iI just finished calibrating gray scale with a light touchup from the Radiance to corect the blue, going to take a look at it now.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Sat May 11, 2013 9:42 pm Post subject: |
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If you would put masking to the bare tube (not the glass face plate) you might get some improvement, maybe, but as others said there are no miracles in the AC technology.
On the other hand you could get sharper image iif you put up a HD145 or even a PT-65 from an old sony, instead of the HD-8.
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projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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stridsvognen
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| Posted: Sat May 11, 2013 10:13 pm Post subject: |
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Would be interesting to hear from someone who have done it, and compared results.. Anyone.?
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HK-Steve
Joined: 15 Jul 2006
Posts: 849
Location: Switzerland
TV/Projector: Marquee 9500, Epson 8100
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| Posted: Sun May 12, 2013 8:42 am Post subject: |
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When I bought my 8111+ of Curt,
first thing I did was put some back material between the tubes to stop the cross tube spill.
It does help.
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stridsvognen
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| Posted: Sun May 12, 2013 9:04 am Post subject: |
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Thanks Steve..
Ill go give it a try.
Dont look like there is much interest in improving contrast on AC machines.
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HK-Steve
Joined: 15 Jul 2006
Posts: 849
Location: Switzerland
TV/Projector: Marquee 9500, Epson 8100
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| Posted: Sun May 12, 2013 9:21 am Post subject: |
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I started with an AC, then went LC, was a great leap forward. Both in sharpness and contrast.
Had the AC for a year before I upgraded.
I played with color filters and clear glycol, colored glycol.
I still have a set of AC lenses that are Aluninium and glass laying around here somewhere.
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stridsvognen
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| Posted: Sun May 12, 2013 9:37 am Post subject: |
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I started with DLP.. then D-ILA--> LC and now AC..
Wonder whats next 
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stridsvognen
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| Posted: Tue May 14, 2013 7:31 pm Post subject: |
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just masked the red tube, and put a border around the glass, that overlaps the lense when mounted, later ill measure a grayscale and see if it changed anything, for now its only on the red tube,
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HK-Steve
Joined: 15 Jul 2006
Posts: 849
Location: Switzerland
TV/Projector: Marquee 9500, Epson 8100
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| Posted: Tue May 14, 2013 8:23 pm Post subject: |
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What are the red vertical lines on the tube face???????
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stridsvognen
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| Posted: Tue May 14, 2013 8:26 pm Post subject: |
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| HK-Steve wrote: | | What are the red vertical lines on the tube face??????? |
Its the test pattern, its just hard to see, the flash covered most of it.
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HK-Steve
Joined: 15 Jul 2006
Posts: 849
Location: Switzerland
TV/Projector: Marquee 9500, Epson 8100
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| Posted: Tue May 14, 2013 8:29 pm Post subject: |
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That is one very nice super white phosphor on the red tube. sweet
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stridsvognen
Guest
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| Posted: Wed May 15, 2013 6:31 am Post subject: |
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Did see some movies on the projector last night, and measured some, i cant see much changes in the measurement, maybe a bit around 20-30% ire, but nothing i'm sure relates to the masking.
But i right away got the feeling of better contrast, cant document it, but i liked it, so the other 2 tubes will get same treatment later.
i think it mostly effects the light output around the screen, and in my room there is no control of the light, so less surrounding light makes a improvement.
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stridsvognen
Guest
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| Posted: Wed May 15, 2013 5:42 pm Post subject: |
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Just finished masking the green and blue tube, so tonight ill have the final result. Its getting dark soon, In 2 hours ill know how it looks.
It cost me 10$ so no matter what, ill survive..
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