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stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
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| Posted: Thu Feb 04, 2010 11:32 am Post subject: AmPro, Image, 1080P |
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Most are aware of this. AmPro's clip off a little bit of the image on the sides of a 1080P image. The image is bigger than the available raster. It can be corrected through the use of a processor by adjusting the porches but what would be needed to correct this within the projector so that a external processor would not be needed? I don't know what "per cent" of the image is lost but I'd say on screen, about a inch on each side. Using a BR DVE test patten, you are just inside the corner circles. By the time you add sufficient overscan to the sides onto your boarders, you end up loosing a couple of inches on each side.
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Chip
A Barco is only a AmPro with training wheels
Card carrying member of the AVS chain gang.
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Thu Feb 04, 2010 1:37 pm Post subject: |
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To make the retrace time shorter the "flyback" pulse, on the HOT output board, has to increase in voltage. The factory parts are rated at 1100V. So if higher voltage mosfets are available the flyback could be shortened with a capacitor value change.
Scott
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Thu Feb 04, 2010 2:28 pm Post subject: |
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I did a little looking and it might be possible. Downside would be slightly worse horizontal linearity at lower sweep rates but probably not an issue at 1080p. Then there is the danger of mucking with deflection circuits. It would be wise to do the testing with a unit that has CRTs that you don't care about. Anyhow, the math works out.
Scott
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"Were we directed from Washington when to sow and when to reap, we would soon want bread."
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
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| Posted: Sat Feb 06, 2010 1:46 am Post subject: |
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| tse wrote: | I did a little looking and it might be possible. Downside would be slightly worse horizontal linearity at lower sweep rates but probably not an issue at 1080p. Then there is the danger of mucking with deflection circuits. It would be wise to do the testing with a unit that has CRTs that you don't care about. Anyhow, the math works out.
Scott |
I have that low hour 3600 hanging in the garage set up on a 100 inch screen.
I assume you are talking about Q-12 through Q-16 and Q-18. You tell me what caps to order and replace and I'll play mad scientist and experiment on my own stuff.....(mad scientist laugh) 
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Chip
A Barco is only a AmPro with training wheels
Card carrying member of the AVS chain gang.
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