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Discussion Starter · #1 ·
I am having a strange problem with input B on my new G70 that I bought last week. I have an IFB-11 RGB card on input B. When feeding a signal from my HTPC, the picture has a red tint that changes in intensity depending on what's showing on the screen. It is more intense when showing dark backgrounds:

http://members.aol.com/vruiz63/picture1.jpeg


When the background gets brighter it then takes a green-red tint:

http://members.aol.com/vruiz63/picture2.jpeg


Needless to say, the picture leaves a lot to be desired:

http://members.aol.com/vruiz63/picture3.jpeg
http://members.aol.com/vruiz63/picture4.jpeg
http://members.aol.com/vruiz63/picture5.jpeg


My previous projector was a Marquee 8000 which did not exhibit any of these problems when fed the same signal from the same HTPC. Also, this only happens on input B of the G70. When I connect the HTPC to input A the picture is fine. I have tried two different IFB-11 cards and the problem remains.


A couple of people have said it could be the color balance or gain/bias but if it was that why would the tint change depending on what's showing? Wouldn't it be the same regardless of the image on the screen? Also, wouldn't that show on input A as well? The fact that it only shows on input B and it's happened with two different cards leads me to believe it may be something with the input itself in the projector.


Anyone has any idea what this could be?
 

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There are a number of jumpers (termination, sync, etc.) on the IFB-11 card that must be properly set in order to work properly. They might have been moved by someone using the card for a different signal.
 

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I don't know if it could have as dramatic effect as your photos show, but wrong bias settings can cause exactly what you're experiencing.


Set the color temp for input B to the same color temp as input A. If gain & bias settings are your problem, that will fix it.
 

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The IFB-11 has jumpers and pots on the board that will allow you to set each RGB color to either FIXED or Variable gain (each colors gain can be adjusted with the pots).


Not sure where your jumpers are, but you can easily remedy this by setting the jumpers (JP6, JP7 and JP8) to the fixed position. If afer doing that the problem still exist, the board should be swapped.


Anyway, never use an IFB11 in the VARIABLE position, if you'll want the cleanest image.
 

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Discussion Starter · #6 ·
Ok, I pulled the board out and checked it. Jumpers JP6, JP7, and JP8 are in the fixed position. All other jumpers are also in the proper position according to Mike's diagram. The problem remains. Anyone else has any ideas?
 

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I didn't see the "diagram" you're referring to, but what about JP-1 and JP-2, they should be set to OFF and the black switch to ON?
 

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Discussion Starter · #10 ·
Yeah, unfortunately all the settings are just as those diagrams say they should be.


I'm getting a third IFB-11 card tomorrow from a different source. If the problem is still there on that one then I don't know what else to do.
 

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Vic,

I find it odd that you have changed the IFB11 already and had the same results.

You said that the color temp on the IFB11 is set to 6500 just like input A. But what anout the bias and gains of all three colors??Are they the same as input A??


Terry
 

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Discussion Starter · #12 ·
Yes they are, but another weird thing is that the gain and bias numbers are the same no matter what input memory I'm in, although they look very different! I know I must be doing something wrong. When I press the gain or bias buttons the picture pops into a 4:3 test pattern, it doesn't stay in 16:9 mode. Is that supposed to be that way?
 

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Vic,


Have you gone into the Servicemans more and hit enter on inputB and made sure that RGB was selected??


Terry
 

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This is about the IFB12 card, but maybe some of this will apply to your situation: http://www.avsforum.com/avs-vb/showt...B12+AND+jumper


Terry, the bias and gain settings for any given color temp are always the same, regardless of input or memory block. If you change them in one input, they will be changed in every input. The memory blocks will only remember which color temp is selected. As least this is true with my G70.
 

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You are correct Phil. I was thinking of something else.


Terry
 

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Vic,


I have an IFB-11 board that I know has good color in my G70, but is goofy in that it takes about 10 min to start working. You are welcome to try it you would like.


Steve
 

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Discussion Starter · #17 ·
Ok, I think I really screwed the pooch now! I decided to do a complete setup from scratch and I did resets on all parameters, including the magnetic focus and bias/gain settings on all 3 colors. Now I can't get the blue focused the way it was before, and even though the red tint on RGB input B diminished significantly (not completely), now the picture has a greenish look on all inputs, including the HDTV component on input A which was perfect before! Someone please save me from myself!


Anyone has any tips on doing grayscale by eye? I don't have access to a color analyzer and I don't want to pay someone to do it now when I'll be moving in a couple of months and was plannning to hire someone to properly do the new setup then.


I'm having a few people over for the Super Bowl and if I don't get this picture right by then we're going to be very unhappy here. :(
 

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Vic,

I don't know why your B focus won't come in but have you used all the adjustments in the focus menu. Position 1 is global and will effect the entire screen.

Sony has some number that are the factory start number for the R, G & B Gain and Bias settings that should get you started. From there (since you are eyeballing) put up a grey "step" pattern, set the color temp to 6500 and use the Bias settings to get the blacks black, and the Gain to get the whites white. These controls will have a slight effect on each other.

Before you do this make sure the ABG is on in the Set Setting menu as it will make it much easier to set your grey scale.



Terry
 
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