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Discussion Starter · #1 ·
Over the last 3 months I have had a problem with my 9pg xtra...


When I turn it on the color balance is sometimes way off and the red tube is very over driven (raster not just the image). By entering and exiting the brightness menu it always fixed the problem and seem to adjust everything to where I had it set in the white balance menu.


Until yesterday..


Now everytime I enter the brightness menu it just fixes it for a second and the returns the red tube to the over driven state. It does the same thing if I enter the white balance menu.


I did fix it last night by hitting the kelvin button in the remote (which I though was the same as white balance). But now the red seems to drop out as more red is used on the screen. i.e. as a large red (or any color made up of red) appears the red tube intensity drops. As you can imagine this really screws with the color balance.


Any thoughts? I have a 6PG xtra I can borrow parts off of temporarily if you have suggestions.


Here is some more supporting information...


1) if I normalize the white balance it puts the projector in a state where it is lacking in red and blue (or too much green). This makes sense as the green tube is new. But the red and blue tubes show no sign of wear.


2) If I enable and AKB from the non over driven state it increases the red too much.


3) the rasters are maximized


4) The properly setup white balance (when things are working right) I am required to use a white balance setting of 80 for the red (W) and 4 for (B). These seem to far into the extremes but provide the best gray scale (or did till last night) I have not touched the G2 settings as things look good with the switch in the test position.


Thanks for any help,

Sandy
 

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Sounds like you need a full CRT drive set up. This is not for the faint of heart, I would get an NEC tech local to you to do this...


Curt
 

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I tend to agree with Curt on that one. I have just done a full setup for someone, and cannot overstate enough that unless you know exactly what you are doing, AND have the right tools, DON'T TRY THIS AT HOME!!!!


I am a video technician by trade, and do have all the tools, including the rubber chicken for fine adjustments, but even then, it can be a 6 to 8 hour job to dial that beast in just right. So... yeah, get an NEC tech. Do not turn any pots.


Marc
 

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Discussion Starter · #4 ·
That certainly doesn't sound like anything I want to try? I just submitted a form on NECs website, but does anyone have a phone number for NEC support in Canada? Maybe they can point me to a local NEC tech. I tried to find someone to change a tube for me back awhile ago and the closest was Kingston Ontario which is about a 13 hour drive.


Sandy
 

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Marc,

Quote:
Originally posted by Tinman
I am a video technician by trade, and do have all the tools, including the rubber chicken for fine adjustments,
I have a rubber chicken, but it has not been calibrated. Should I have it calibrated before using it for adjustments? And what would be the best way to use my calibrated rubber chicken? Since it's Thanksgiving, would a rubber turkey be better?


:D


Regards,


Ira
 

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Well, that's a good question.....


See.. the rubber chicken has to be a certain weight, yet still have just enough bounce. I think a rubber Turkey may be good for rough-in adjustments, followed by the rubber chicken for the more delicate final touches.


Marc
 

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Personally I like my rubber chicken to be nice and warmed up before use. It adds that nice snap to the flailing of the chook's limbs when waved with vigour over the whimpering innards of the projector as part of a voodoo ritual.


Just the thing for solving those control interdependency problems.


:) ;) :)


- David Eddy
 

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Good luck finding a competent NEC tech in Canada, I live in Kingston, and I'm pretty sure there aren't even any here. You *might*find one in Ottawa, but is that getting closer or farther from you ? There's a really good NEC/overall tech in the NE NH MA area of the US(or maybe two) is that closer to you ? You can get a form at the border which tells customs you are only bringing something across for repair.
 

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Discussion Starter · #10 ·
MA and NH are closer. Still not close but closer. Could you send me the contact info and I will give them a call.


I spent some more time with the unit tonight so here are a more detailed set of symptomes.


Any time the AKB is enabled (brightness or white balance) the red tube will vary in intensity with the image that is on the screen. If the screen has a bright image like a gray scale ramp then the red tube's output will start to be over driven. But if you were to change the image to a black image the red tube output will drop back to normal. It actually fluctuates depending on the content being displayed. (remember this is only when the AKB is on). The soon as you leave the menu the red tube output stays at whereever it was when you left the menu.


For 16:9 content the image quality doesn't seem to be affected at all. It looks fine. But for brightly lit 4:3 content like Superspeedway the red tube cannot keep up to it's require intensity and the image will turn toward a blueish green. Interestingly if I pull up the adjustment menu during one of bright scenes the black background of the menu will provide enough relief for the red in the image to return to where it should be. Almost the opposite effect than what it was doing with the AKB enabled above in the brightness menu. It is like the AKB is trying to compensate for the red dropout.


I tried reducing the ampliture thinking maybe with a smaller raster the problem might go away, but it didn't.


Does this still lead you guys to believe that it is the CRT drive, or could it be whatever drives the red tube is clipping too soon.


I also just displayed a red image in windows. If the image is small it is brilient red. If I blow up that same red to fill the screen it becomes very dull in color. Just another test verifiing what I was noticing above.
 

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Discussion Starter · #11 ·
Sorry for the spelling errors guys, I feel a little embarrassed. I spell checked the message with the forum spelling checker, but the insert window ended up behind the original and it didn't get inserted.


Sorry
 

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Discussion Starter · #12 ·
Well after many and several days of attempted fixes and hours swapping parts with the 6PG xtra chassis I had here, the solution to the changing intensity of red as more appeared on the screen was a bad neck board.


I replaced the RED neck board and everything returned to normal. I wish I would have tried this first instead of all the other parts/boards I swapped first. All that said, I am soooo happy. Now I need I new neck board for the 6PG xtra chassis I borrowed the replacement out of. Curt, I will be contacting you shortly.


I figure it was worth posting the solution here in the case that someone else runs into the same problem someday.


Sandy
 
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