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rgb amp help!

Discussion in 'General Electronics Discussion' started by Drakon, Jan 28, 2011.

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  1. Drakon

    Drakon

    1
    0
    Jan 28, 2011
    Hi I modified an av famicom (japanese nes 2) to use a rgb ppu chip from a playchoice arcade pcb. The picture looks excellent when it's unamped but it's much much too dark. So I built a few different rgb amps and they do a great job of making the picture bright enough but as a side effect they cause this annoying white border to appear around graphics (mostly on the right side). I'm using a rgb to s-video encoder pcb to convert the signal to s-video. This encoder works fine on all of my other console systems and arcade boards.

    Here's some comparison pictures of what the image looks like when it's being amped and when it's not being amped. The first picture is how it looks after I run it through a simple 2sc1815 rgb amp and the second picture is how it looks with no amp and my tv contrast and brightness turned to full power:

    [​IMG]

    [​IMG]



    [​IMG]

    [​IMG]



    [​IMG]

    [​IMG]

    Here's the links of the amps I've built and tried:

    http://www.gamesx.com/grafx/pce_rgb.jpg

    http://gamesx.com/wiki/doku.php?id=av:nes_rgb_amplifier

    http://baku.homeunix.net/RGB/RGB_FC/RGB_FC.html

    All three of these amps have the white border. I also took some screenshots of the picture using my capture card:

    [​IMG]

    [​IMG]

    [​IMG]

    These screenshots were taken from the same s-video signal that goes into my tv and causes that annoying white border. But the screenshots look fine however it looks terrible on my tv. Any help is greatly appreciated

    *edit* oh and also the s-video on the tv works fine. I also connected my tv to my pc, other consoles, and even use the same s-video encoder with other consoles and the tv gets a perfect looking s-video picture.
     
    Last edited: Jan 28, 2011
  2. shrtrnd

    shrtrnd

    3,823
    519
    Jan 15, 2010
    Probably can't help, but some possibilities to consider.
    1) Any stop-gap boards, between the conversion of analog to digital in TV's lately.
    2) Any problem with systems (or games) marketed to a particular region, not compatible with what you're using.
    3) Really, your problem looks to me like a tuning problem. Is your signal TUNED to
    the TV you're using?
    Good luck
     
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