S video black and white screen help

Discussion in 'General Electronics Chat' started by dazzer7, May 14, 2016.

  1. dazzer7

    Thread Starter New Member

    May 7, 2016
    5
    0
    I have a super ~Nintendo console and I have noticed when using S-video the games play in black and white , Now I have come to the conclusion that the problem is on the board some where , Now when I do use S-video it shows a black and white picture this should mean there must be a Y luma signal that is working but the C chroma is not . I would like to know if anyone has any ideas of what it could be and maybe a fix >?

    I also was thinking of trying this taking the C chroma signal from the (S-RGB A ) chip which on mine is called (S-EWC 92224 M60F) solder wire to pin 12 with 100nf Cap and 75 ohms resistor then solder this to the C chroma pin 8 on the multi AV out which in order to trying and bypass the problem , This is just a long shot what do you guys think I should do?>
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    I would first check the cables and pins carefully, interchanging sources and monitors to isolate where the problem is. It could be as mundane as a crushed pin in a connector or a faulty cable.
     
  3. dazzer7

    Thread Starter New Member

    May 7, 2016
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    0
    Hi! Cable is working tried with another console I would also like to point out that AV is working just not s-video , I did check the pins too they looked ok.
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    Any idea if you can probe the chroma signal to find it on your board?
     
  5. dazzer7

    Thread Starter New Member

    May 7, 2016
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    I know where the C chroma signal is or should be just not sure how to test it.
     
  6. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,972
    744
    You're going to need an Oscilloscope to view the signals.
     
  7. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,518
    1,247
    Starting with pin 3 on the connector and working backwards through the circuit, you are looking for an amplitude modulated 3.58 MHz sinewave, about 0.5 Vpp for bright colors.

    ak
     
  8. Andrew Hodson

    New Member

    May 26, 2016
    5
    1
    Yeah, some TVs only show s-video in B&W. just do ½ the job.
     
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