NESRGB no red on RGB

Discussion in 'Modding and Hacking - Consoles and Electronics' started by Mamejay, Mar 14, 2015.

  1. Mamejay

    Mamejay Robust Member

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    Hey guys,
    I was asked to install a NESRGB for a friend. It is a NTSC front loader.
    I managed to install it and get S-video working perfectly but when using SCART RGB it looks like there is not red.
    I have checked the connections direct from the NESRGB board to the SCART connector and it is definitely connected.
    I suspect the board is fine as if it wasn't I would have no red while using S-video also.
    Anyway I have emailed eTim but he is away till the 27th and I want to get this one closed off.
    On the board there is a JP5 that needs to be closed for front loaders but I am not sure if JP3 needs to be closed also like the famicom.
    I am using C-sync but got the same result using composite.
    Any advise on this one?
    Attached is a couple of pictures to show you want I mean.
    20150315_114051.jpg 20150315_114102.jpg
     
  2. mickcris

    mickcris Site Supporter 2014,2015

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  3. adimifus

    adimifus <B>Site Supporter 2013</B><BR><B>Site Supporter 20

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    It seems to me, if s-video looks fine, that the RGB going into the encoder is fine, but the problem is probably closer to the red out contact on the NESRGB. Maybe the capacitor isn't solered down on one side?
     
  4. Bad_Ad84

    Bad_Ad84 The Tick

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    Got a scope? Just start tracing back from the red output at the TV side until you find the signal
     
  5. retrofixes

    retrofixes Site Supporter 2014,2015

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    Gosh, I've installed many of these boards and seen a few gremlins in my day.

    What type/brand of scart cable are you using? I've seen many crummy mis wired scart cables
    What output method are you using for RGB? Mini Din?

    Are you sure Red & Blue is installed correctly (to the cable port) and not reversed. Easy goofup
     
    Last edited: Mar 15, 2015
  6. crans

    crans Rising Member

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    ditto on checking your scart. I have seen factory scart with bad caps and also on nesrgb i have not made with the cap and risistor inline on the scart hood and all is well
     
  7. Mamejay

    Mamejay Robust Member

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    Unfortunately I don't have a scope so no luck there. I have made my own cable using the mini din connector provided. I am sure that red is connected as I have been connecting the SCART lead to the NES and then doing continuity tests direct from the red contact of the NESRGB board to pin 15 of the SCART connector. I have checked it about 10 times so far.

    Is it possible to find out if the signal is being generated using other methods? IE check the voltage of the red output using a MM?

     
  8. AhmedXyz

    AhmedXyz Rapidly Rising Member

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    Desolder green and blue and see if you get anything at all. If not, solder green or blue to red and see if you get red.
     
  9. adimifus

    adimifus <B>Site Supporter 2013</B><BR><B>Site Supporter 20

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    Since s-video works fine, it's either your cable, a bad connection between the NESRGB and the jack, or something with the red output trace on the NESRGB itself. The first two should be very easy to work out with a multimeter. The third, just work your way from the solder pad back until you find a break in continuity.
     
  10. Mamejay

    Mamejay Robust Member

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    Well I feel like a dofus. Just checked everything again and found that on the back of the RGB jack red and 5V had bridged. Removed the bridge and presto. Full colour rock solid image.
    Thanks guys for the advice.
     
  11. retrofixes

    retrofixes Site Supporter 2014,2015

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    Good job. That would explain why it passed continuity tests.
     

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