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Discussion Starter · #1 ·
Hi,


I have tried strengthening the ground on the Xcapture with decent results. Chroma noise is significantly reduced. Luma noise is also reduced, though not as much.


There are two solder bridges, as shown in the images. I used a small screwdriver to scratch out the enamel on the PCB. Be sure not to scratch the enamel on the area that is to be bridged over, or you run the risk of a short circuit.


I used some braided de-soldering wire as a base for the solder bridge. Desoldering braids are readily available at electronic repair stores. Alternately, you could use the ground conductor of a coaxial wire.


I am not sure if you need a thick solder bridge at all. A simple wire might work as well. I used the thick bridge just to be sure.


-T
 

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Far be it for me to question this mod, as I'm sure it works. But why wasn't this "mod" done by the company? How is it that they can ship a noisy card, and yet simple soldering can increase the picture quality? This makes me wonder about the quality of these products...
 

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L1st3r-


Who said the factory ships a "noisy" card in the first place? This chipset offers a better feature set than any other card for Dscaler that I know of for the price.


Why do folks modify BMW's, Porsche's, Ferrari's, Corvette's, etc.? This makes me think that these cars are flawed when new. Come on buddy, it's all about getting the best 'bang for the buck', and having a little fun as well.


Thanks tsingh for devising this tweak!


-PGPfan
 

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Discussion Starter · #5 ·
I forgot to mention that I observed the improvement on the S-Video input. I didn't check the composite input.


As for why the manufacturers didn't do it in the first place, perhaps the card worked well on the designer's computers. This card does well work on most computers, the modification is aimed at making it work well in noisy environments as well.


Regards,

T
 

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T,

Could you email me a copy of the original photo of your mod? I'm guessing the original jpg has more detail. I think I can tell what you've done from the picture and description, but would like to be sure what I'm doing before I pull the card and screw up a perfectly good setup. :)


I should have time to mod the card this week and will post my findings.
 

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Discussion Starter · #7 ·
My original jpeg is no better, unfortunately. I'll try to take a better picture tonight.


Regards,

Tripurari
 

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Discussion Starter · #8 ·
If you don't want to wait for new pictures, you could use a multimeter to verify that you are connecting two ground planes. There are no other ground planes nearby to cause confusion.


To verify if something is a ground plane, scratch off its enamel and see if it is connected to the chasis.


-T
 

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I wonder if it would be easy to solder a few metal standoffs to a blank PC board the size of the X-capture board, giving you a full ground plane and some measure of shielding at the same time?
 

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Discussion Starter · #10 ·
It should definitely help, I would love to see the results of that mod. Unfortunately, I destroyed the svideo circuit of my Xcapture with my latest modification attempt, so I can't try it out.


Please keep me posted, I am still interested in the Xcapture.


Tripurari


ps: Moving my card to the slot closest to the PC case helped with the noise. This bodes well for your modification.
 

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My impression of the above mods thus far are not favorable. are you certain that your lower bridge is connecting two ground planes? from what i can tell from my ohm meter the upper bridge is connecting two ground planes while the lower one is not. against better judgement i made the lower bridge anyway and no great surprise the card didnt work. after removing it the card works again although I am now plaqued by faint diagonal scrolling lines. I will remove the upper bridge tommorow with the hope that the card will be back to baseline.
 

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Discussion Starter · #13 ·
Rick,


The lower bridge has to be connected to the small triangular area directly leading to the CX23881. See the attached image; connect to the checked area and not the crossed area.


When connecting groundplanes, you can worsen the noise if you connect a clean and critical ground plane to a dirty and not so critical ground plane.


Reversing the modifications should bring your card back to baseline. Get as much solder out as possible and make sure that the remaining is flat and smooth with no sharp protrusions.


Keep me posted.

Tripurari
 

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Hi,


This is a translation of the following thread, sorry it's a french forum and there is not yet any picture !

http://www.homecinema-fr.com/forum/v...light=xcapture


Despite it's quality, its true that this board have some bad point (noise) :

- Noise from PC Power Suply

- Noise from PC internal EMI

- Noise goes to the inputs


So we have to shield as much as possible the boards and inputs.

The Svideo inputs it's at abaout 7cm from the CX23881 and there is not that good caps on the path.


You can use 3 good coax cable (2 for Y/C, 1 for composite) 6 good quality caps (paper or polypropylene + 10nF plast.). 3 220 Ohms resistors (metal) and 3 RFI 10MHz filters.


RFI filters and caps must be wired close to the CX23881. Resistors must be wired after this between signal path and ground.

Then the coax cables goes directly to the connectors.


Shielding the board. Two piece of epoxy + copper (classic electronic plates) could be installed on each face of the board, shielded to ground.


No work has been (yet) done on power supply noise filtering.


Some pictures should follow...


Hope this helps, at least the improvement are nice ;)


Thanks to BladeRunner.


--Patrice
 

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Discussion Starter · #15 ·
Here's a simple "mod" suggested by RTK - remove the lid of the PC case! A closed case reflects the electromagnetic waves back into the PC thus increasing their intensity.


I had previously observed the same effect with my old IOMagic card. I can't verify the effect with my Xcapture because I destroyed it in a shielding experiment.


You can make your circuit immune to EMI by placing a ground line close to the signal line or by shielding the line outright. You can also route the signal away from strong sources of EM.


One interesting difference between the XCapture and ASUS is that the ASUS routes the video lines near the top edge of the card - ie. as far from the motherboard as possible. The Xcapture, on the other hand, routes it through the middle.


-Tripurari
 

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Quote:
Originally posted by PGPFan
This chipset offers a better feature set than any other card for Dscaler that I know of for the price.
Last time I checked (just a week or so ago) on dscaler.org, it specifically lists this card as *not* supported (though they were planning to support it at some point in the future)... ???


I was pretty interested in this card until I saw that. Are there new developments that I'm unaware of on this front?
 

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Hi,


There is a beta version of Dscaler (4.1.3) working with XCapture (and more generaly CXxxx chips)...


To my knowledge it should be remeased pretty soon...


I can tell you that it's really stable and working fine.


--Patrice
 

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Discussion Starter · #19 ·
Laric,


That's a lot of modifications, can you tell us which ones were particularly effective? Not all of us have the energy/inclination to do them all.


Regards,

T
 
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