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Discussion Starter · #1 ·
Ok, I am just getting a Barco 808 setup well and noticed during movies and television last night that there was a light streak or "vapor trail" to the right of all bright small objects against darker backgrounds. Its almost like a smear of whatever that bright color is all the way to the edge of the screen. What is this a symptom of? FWIW, a search on the forum revealed a thread on Sony 1292 but no definitive answers that I could see.


Brian
 

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My marquee 9000 had a similar problem on just the blue. Bright pixels caused dim pixels to the right to be brighter, making a scene with stars have lines instead. The problem was a bad transistor in the VNB. Hope it is the same in your case. It is very simple to repair. Since I did not know which transistor to replace(no oscilliscope), I just replaced all 5 of them.
 

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Bran,

If this is the 808 I think it is turn the contrast down and it will go away without any loss of contrast. It runs very low on this machine.


Terry
 

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Discussion Starter · #4 ·
Thanks Terry it tis true that I have not set contrast and brightness by Avia yet but I wondered if there were any issues otherwise. I bought the 808 from Jason in Nashville and it sounds like you knew that. I have noticed that contrast and brightness ARE very low compared to other's. Brian
 

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I'm seeing this on my 808 as well. What's worth to note in my case is that the streaking only occurs on gray backgrounds, never black - and it seems to affect all colors. I've tried this using Paint Shop Pro on the HTPC - moving the mouse over a black background is OK, but dark gray it produces streaking.
 

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brian,


For some reason that particular 808 needs the contrast set lower by the numbers. It is still putting out full light but the number reads very low on the contrast setting.


Terry
 

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Discussion Starter · #7 ·
Well I lowered the contrast to about 18 last night for a movie and while it did significantly reduce the streaks it did not eliminate them. In one scene it looked like a lady had laser beams coming out of here eyes. I did not try any lower and still have not set contrast per AVIA so I will post back when I have done so.


I also noticed another phenomena. I have a vertical bar a few inches in from the left edge of the screen that is slightly different contrast than the surrounding picture. I have not noticed it when watching hidef sources via pass-through on a quadscan elite but definitely do notice it with any sources passing through the component inputs. It could be something in the signal path but I will have to check more. It could also be that the picture and raster shift is in a slightly different position with that source.


I had a similar problem with a Toshiba RPTV except that there were numerous bars on all sources and signals. It was localized to their boards but they could not fix the problem so they bought the television back from me.


Brian
 

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Brian, the slightly different constrast stripe sounds like the memory blocks are slightly different, placing the image area (or the raster area) on different parts of the tube for the two different signals.


Try finding out the memory block used when you run HD pass-through, and then run using the quadscan and copy the memory block from the HD memory block to the current one. You can also try using the h-phase to shift the image within the raster and see if that "fixes" the contrast problem.


If you are outside of the worn area, you will see a difference, I get this on my outer 2" on either side, and just ignore it.
 

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Discussion Starter · #9 ·
Thanks for the tip. Something else I noticed last night was that I could not get a 720p pass through to fill my screen horizontally while the 1080i pass through does. This is from a Zenith 1080i HiDef box. I though this was strange.


Regarding the memory blocks...I still have not figured this stuff out. I dont fully understand what exactly they do, or what is happening when you copy a block. I just know that every time I set up a new input signal (480p, 720p, 960p, 1080i, etc.) I have told it to copy and it apparently saves my settings. So how exactly do you copy the memory block from the HD Memory block to "the current one?" I am assuming you select copy then pick the 1080i-Source 4 and press copy and it will copy that to my 960p-Source 4?


Brian


Brian
 

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Brian

Regarding the smearing you are noticing. It could also be from G2 settings being too high. Take a look at the video O/P boards and see if the little green LED is out as it should be. Theses are the three boards mounted beside each other and to the frame just above each CRT.

Steve
 

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Brian, to copy a block to the current one:


Send in the signal you want to "reconfigure".


Adj

"Service"

"Copy Block"

Select the source block


And it'll overwrite the current block with the other one. To find out what block you want to copy from, send in the "source" signal, go to the same "Copy Block" screen, and you'll see a note (I think on the bottom) indicating the current block number. Remember this value, back out of the menus, and switch sources, then do the copy.


The memory block deal on a Barco (and most other projectors) is just a set of slots in memory where the projector stores all convergence information. When the projector fires up, it downloads the convergence data from the memory block(s) and uses that to properly control the electron beams to produce a nicely converged image. Geometry is also stored with the memory block.


Each different input frequency (both H and V sync rates) results in a little different behavior within the projector as it processes and displays that signal. Consequently, minor changes in H and V sync can result in the image being placed differently on the tube faces, requiring small corrections in geometry and convergence.


Thus, each frequency pair maps to a unique memory block, allowing the projector to store these corrections.
 

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Discussion Starter · #12 ·
Thanks Spearce,

Quote:
Each different input frequency (both H and V sync rates) results in a little different behavior within the projector as it processes and displays that signal. Consequently, minor changes in H and V sync can result in the image being placed differently on the tube faces, requiring small corrections in geometry and convergence.
Well that might explain why when I changed from input A to input B on my Quadscan Elite I initially could not get the two to sinc up though there should be no difference whatsoever. I switched back and forth a few times and it then sinced up with the right settings.


Regarding the streaking/smearing, I had to set the contrast down to around 5-10 range to get rid of it! Man, how can that be right? I might need to investigate some more the G2 issue.


Brian
 

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Those green lights on the neck boards are supposed to be out? Crap. I should have read the manual.


Good luck with the smearing problem. I had two independent problems causing smearing on a 800 I used to have. One was a tired output transistor on the neck board, and the other was crappy interconnect cable.


-Garrick
 
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