GameCube cable RGB

Discussion in 'Modding and Hacking - Consoles and Electronics' started by simonbelmont2, Feb 26, 2010.

  1. Today I received the gamecube cable (made by MaDrics) and everything is ok for the moment, but when I opened the cable I saw that one rezistor and one capacitor is missing.
    On this diagram http://members.optusnet.com.au/eviltim/gamescart/gamecube.png you can see that the pin 18 and 20 are wired with one rezistor and one capacitor.
    Can someone tell me for what are used?

    Thanks!
     
    Last edited by a moderator: Feb 26, 2010
  2. Oldgamingfart

    Oldgamingfart Enthusiastic Member

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    I think the output level of RGB and Composite video is higher on the Gamecube, then say the European SNES for instance. These components bring the output levels down a notch so that the picture isn't too bright or over saturated on some TV's.
     
  3. Pin 18 on the scart diagram (http://www.leadsdirect.co.uk/images/technical/scartdiag.gif) is for "RGB blanking ground" and pin 20 is for "composite video input".
    So maybe the capacitor is used for what you have said but I think the rezistor on pin 18 is wrong wired on the diagram.
    If anybody have other suggestions I will be happy to hear them.
    Thanks!
     
    Last edited by a moderator: Feb 28, 2010
  4. link83

    link83 Enthusiastic Member

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    The diagram isn't wrong, it matches the components used in an official PAL GameCube RGB SCART cable (Although one of the resistor values is slightly different)

    The 75ohm resistor to ground lowers the brightness of the composite video signal, and the 220uF capacitor removes the DC offset from the composite video signal. Only PAL GameCube's need these components on composite video, NTSC Nintendo consoles dont (Although the NTSC GameCube doesn't output RGB from the analog AV port anyway)

    Without these components the composite video signal will not be at at the 'perfect' level, and since RGB SCART uses the C-Sync signal from composite video you may see the picture 'jump' occasionally (Especially on bright images) as the sync messes up, although any visable effects will depend entirely on the TV and the way it processes the sync signal.

    I dont know how 'safe' it is for the TV to have slightly incorrect signals though? :shrug:
     
    Last edited: Feb 28, 2010
  5. Thank you Link83 for your response and informations. About the cable, for the moment is working nice without the resistor and capacitor and I don't have problems with "picture jump" but for the future is necessary to wire the rezistor and the capacitor to pin 18 and 20?
    Another question: it is necessary to wire all the grounds?

    Thanks!
     
    Last edited by a moderator: Feb 28, 2010
  6. link83

    link83 Enthusiastic Member

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    Its probably a good idea to add the the resistor and capacitor if possible, but if you cant see any sync problems without them then its probably not much of a problem for you - but I had sync 'jump' problems on my TV without them. Almost all third-party GameCube RGB SCART cables I have seen do not have these components :rolleyes:

    I dont believe it is necessary to wire all the grounds at all, even the official cable does not use all the available ground pins.
     
    Last edited: Feb 28, 2010
  7. Thank you again! By the way, sync problems have something to do with the image settings (horizontal and vertical resolution) because on some NTSC games on my PAL console (modded with xenogc 2.0) the image is not "streched" like in the PAL games; the horizontal or vertical resolution are a bit sync-out.
    Do you know what cause this problem?

    Thanks!
     
  8. link83

    link83 Enthusiastic Member

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    Sorry, I am not sure I fully understand what the problem is. Are you just refering to the resolution difference between NTSC(480i) and PAL(576i) games?
     
    Last edited: Mar 1, 2010
  9. The problem is on some games I need to calibrate the image (the x and y axes or something like that; this problem I have with my PS2 PAL modded).
     
  10. link83

    link83 Enthusiastic Member

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    Sorry, I dont know about the PS2, although it sounds like its an issue with the way your TV processes NTSC and PAL resolutions.
     

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