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radar
Joined: 05 Dec 2007
Posts: 72
Location: Sydney, Australia
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| Posted: Fri Nov 07, 2008 1:24 am Post subject: Time to replace tube on Marquee 8500? Grayscale problems. |
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I'm having trouble with grayscale and sharpness and I suspect its to do with the red tube. I have a 'new' Marquee 8500 with 11k hours on the chassis, but the green and blue seem to have been replaced at some point. Also, the date on the front of the machine has "October 1996" on it, yet some of the boards have 1997 printed on it! But thats another story.
All three tubes look to be about a 7.5 on Curts wear chart.
Filliment voltage is 6.3 (HVPS and LVPS mods done).
Back to my question. To get G2 right, I've pushed up the G2 so I can 'barely' just see the second last box on the stairstep pattern on each of the tubes. Contrast and briteness at '50'. I also have HD144 color filtered lenses.
Green=61 The focus on green is reasonable, just being able to see the scan lines
Red=81 The focus on red seems soft on edges, cannot see scan lines and astig
and electronic and optical focus is as best as I can get it
Blue=75 The focus on blue is similar to red (but to be expected right?)
The sharpness overall is about the same as the best I could get on my old Barco 701 with 2500 hours on it. I know that the Marquee 8500 can deliver much more sharpness... so I suspect a fault somewhere.
On the grayscale, I get a greenish tinge around the middle of the grayscale. Pushing down Green drive does not help much.
So folks... based on your expert opinion... should I replace the RED tube? or do I need to tweak something I don't know about?
Thanks!
Kevin.
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Fri Nov 07, 2008 1:55 am Post subject: |
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Hello
Your red tube is gone and blue is close behind it.
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Fri Nov 07, 2008 2:00 am Post subject: Re: Time to replace tube on Marquee 8500? Grayscale problems |
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| radar wrote: | | Red=81 The focus on red seems soft on edges, cannot see scan lines and astig. |
your red tube is shot, stick a fork in it it's done, kaput. there was an almost new one on e-bay recently for $50.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=330281035256
BTW your blue's a little weak too but still useable. For perspective brand new tubes dial in around 55 to 62.
| radar wrote: | | The sharpness overall is about the same as the best I could get on my old Barco 701 with 2500 hours on it. I know that the Marquee 8500 can deliver much more sharpness... so I suspect a fault somewhere.. |
sometghing is VERY worng if the 701 ES focus machine was just as sharp. I'm going to suspect bad caps on the video neck boards or possibly a bad focus module?
| radar wrote: | On the grayscale, I get a greenish tinge around the middle of the grayscale. Pushing down Green drive does not help much.
So folks... based on your expert opinion... should I replace the RED tube? or do I need to tweak something I don't know about?Thanks!
Kevin. |
go into color temperature and even out the zones. Usually I set left/right at default 50, for anamorphic squeeze upper/lower around 45, and the 4 corners at 60. This gives fairly uniform screen brightness and is about as close as you can without a colorameter.
don't try to use contras tmodualtion to even out tube wear, it's not going to work.
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radar
Joined: 05 Dec 2007
Posts: 72
Location: Sydney, Australia
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| Posted: Fri Nov 07, 2008 2:26 am Post subject: |
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Thanks folks....
Thanks Dragonm for those extra brightness tips as well!
Looks like I'm up for a red tube....if anyone is looking, feel free to pm me if you have a low hour one. I'm happy to pay around $50 bucks for a good one. Unfortunately, the e-bay one is gone.
Thanks,
Kevin.
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Zebu Fellenz
Joined: 21 Dec 2006
Posts: 2567
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| Posted: Fri Nov 07, 2008 2:33 am Post subject: |
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You may still want to contact the ebay seller, it ended with no bids so it may still be available
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radar
Joined: 05 Dec 2007
Posts: 72
Location: Sydney, Australia
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| Posted: Fri Nov 07, 2008 2:41 am Post subject: |
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I checked... unfortunately its already sold..... 
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