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Composite From Video Encoder Or Gpu ?


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#1 GIGA 24/7

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Posted 27 July 2007 - 06:04 PM

does anyone know if I can get an composite signal from a pin on the conexant chip or the gpu,
cause i have no Volt on the composite pin at the av connector.

It's an xbox version 1.0 pal.
This is the product sheet of the conexant video encoder if someone understand something about it :Link



THX
GIGA 24/7



PS: sorry for my english, i'm a german

#2 DarkMatter

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Posted 29 July 2007 - 01:21 AM

If your getting no video, then you need to check the surfacemount inductor L4A1 to see if it has gone open circuit. See Pic.

IPB Image

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DarkMatter

#3 GIGA 24/7

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Posted 29 July 2007 - 06:54 PM

I don't know what i should look for?
i can only see an black cube without an wire or something
or did i have to make an wire link like the red line???

greetz
GIGA 24/7


#4 DarkMatter

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Posted 30 July 2007 - 12:50 AM

Follow the link below. It will take you to a small turorial I wrote on another Forum, it will show you what you need to do.
Don't worry if your motherboard looks a bit different, the component in question is the same. You only really need to perform the first check. All the other checks will not pertain to your motherboard, so don't try doing them, you'll find the parts in question won't exist on yours.
http://jansforums.jc...wtopic.php?t=76
Regards,
DarkMatter

Edited by DarkMatter, 30 July 2007 - 12:53 AM.


#5 GIGA 24/7

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Posted 30 July 2007 - 05:37 PM

Thank you DarkMatter!!!

Ok I have about 2 Ohm on the L4A1, so you think the Video Encoder chip is damaged?

Small question: do you know if DACA, DACB, DACC, DACD on the conexant productsheet is something about a video output?

Thanks
GIGA 24/7

#6 DarkMatter

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Posted 31 July 2007 - 01:30 AM

QUOTE
Thank you DarkMatter!!!

Your welcome. wink.gif

QUOTE
Ok I have about 2 Ohm on the L4A1, so you think the Video Encoder chip is damaged?

Yes, there is a possibility that the video encoder IC is damaged. But it can also be the GPU IC as well. Its very hard to say what the cause is.
If you can, try setting your X-Box up using component cables instead of a composite video signal. I have come across one X-Box in the distant past that wouldn't work with composite, but worked ok via component, which I found to be a bit strange. I'm guessing that the DAC element for composite was damaged only inside the IC, since each of the four outputs uses its own digital to analogue conversion (DAC).

QUOTE
Small question: do you know if DACA, DACB, DACC, DACD on the conexant productsheet is something about a video output?

The DACA to DACD are analogue outputs, but DACD is for composite output (Pin 66), while DACA to DACC are for component (pins 68, 70 and 72).

If your able to connect your X-Box via component cables and it works, then leave it at that. But if the component cables give you no video as well, then either the Conexant is faulty or the GPU.
If you had acess to an oscilloscope you could find out definately if there's any video present at any of the DACA to DACD points.
I've found that when an X-Box has no video and the L4A1 inductor is ok and refuses to work with component cables, the motherboard is usually a throw away. There are very few people that would attempt to replace the video encoder IC. It requires good skills and the right tools.
Sorry to be the barer of bad news. sad.gif
Please keep me posted on what you find if you do decide to use component cables.
Regards,
DarkMatter




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