SNES US / SuperCIC / Image flickering in 50hz and white flashing in some games

Discussion in 'Modding and Hacking - Consoles and Electronics' started by p4r4d0x86, Feb 10, 2014.

  1. p4r4d0x86

    p4r4d0x86 Member

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    Hi all,

    I have purchased a SuperCIC to Bad_Ad84 and I tweaked my US SNES properly.

    My TV is a french one from samsung : UE40F6640.

    I am in France so my input is 50hz, but whatever, SNES uses DC. I found a compatible DC converter with the positive and negative pole at right place in the connector.

    I use RGB cable on my US SNES (PAL GameCube one with capacitors) like required (see http://gamesx.com/wiki/doku.php?id=av:nintendomultiav to understand)
    So the problem below is not a problem of NTSC or PAL decoding for me. And the cable is ok/perfect (see below in same case)

    If I play Super Mario World US cartbridge on my US SNES in 60 Hz ==> No problem, perfect
    If I play Super Mario World US cartbridge on my US SNES in 50 Hz ==> lateral image flickering

    If I play Super Mario World 2 Yoshi Island EU/PAL cartbridge on my US SNES in 60 Hz ==> No problem (some glitch at start and nothing after)
    If I play Super Mario World 2 Yoshi Island EU/PAL cartbridge on my US SNES in 50 Hz ==> lateral image flickering

    After those tests, I was thinking my US SNES doesn't like 50 hz !? but why ? :(

    Yesterday, I tested Super Mario All stars EU/PAL cartbrdige (Super Mario 1,2,3 NES game adapted for SNES) on my US SNES.
    If I play Super Mario 1 EU/PAL cartbridge on my US SNES in 60 Hz ==> Random white flashing in game especially if there is lateral scrolling, no problem in some part of the game
    If I play Super Mario 1 EU/PAL cartbridge on my US SNES in 50 Hz ==> a lot of lateral image flickering
    If I play Super Mario 3 EU/PAL cartbridge on my US SNES in 60 Hz ==> No problem
    If I play Super Mario 3 EU/PAL cartbridge on my US SNES in 50 Hz ==> lateral image flickering

    Any idea of what is the problem ? A damage component ? Capacitor ?

    I don't understand why I have problem with "50hz" (EU/PAL) games if I run my games on my US SNES in 50 hz ? (I could understand if I was forcing 60hz on EU/PAL games "optimized" for 50 hz)

    Maybe my 50hz TV with the 50hz signal produced with a 60hz console moded ? Samsung TV option to disable ?

    Thanks in advance for your advices :)
     
    Last edited: Feb 10, 2014
  2. sanni

    sanni Intrepid Member

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    This is a known problem that can appear with the following games:
    Super Mario Allstars
    Super Mario Allstars & Super Mario World
    Super Mario Kart
    Super Mario World
    Starfox
     
  3. p4r4d0x86

    p4r4d0x86 Member

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    Ok, thanks for the answer sanni !
    No luck, I tested only games with problem ...

    But, why 50hz is not stable with EU/PAL cartbridge of SMW 2 - Yoshi Island (not listed) ?
    I will test with other EU/PAL cartbridge in 50 hz. Hope the 50hz will be stable.
     
    Last edited: Feb 10, 2014
  4. sanni

    sanni Intrepid Member

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    Remove/bridge the one capacitor from the PAL RGB cable that connects to Scart Pin 20, which provides the sync signal.

    This is how the RGB cable should be for a NTSC console:

    [​IMG]

    See only 3 capacitors not 4 like in your RGB cable.
     
  5. p4r4d0x86

    p4r4d0x86 Member

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    Thanks a lot sanni for helping me :)
    I will have a look to my PAL Gamegube cable used with my US SNES.
    (Just in case it is this one http://www.amazon.fr/Cable-MAD-CATZ-RGB-gamecube/dp/B0000902BD)

    But if it was a signal problem, I should have problem also in 60Hz no ?
    I just tested 5 others PAL games : in 50 Hz same problem for every game, in 60Hz some are OK (accelerated or not) and some have flashing problem (accelerated or not)
    It seems to be two different problems :
    - I have sync problem in 50 Hz
    - Some PAL games can't be accelerated/played at 60Hz : that's fine - no problem (there is lists of incompatibity on Internet)
     
  6. p4r4d0x86

    p4r4d0x86 Member

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    I opened my cable. I had only 3 capacitors (one by color)
    And one resistor on pin 16, and two between pin 2 and 4 and pin 4 and 6
    But this was on the scart side of the cable.

    With multimeter, I detected there was indeed a capacitor between PIN 20 of scart and PIN 9 of SNES side.

    It was not in composite "box" on mad catz cable but in the SNES connector !

    I removed it but it changed nothing.

    Any other idea ?
    A way to improve quality or strengh of sync signal on SNES ?

    P.S. I read that some french users used to have the same problem with 60Hz on their modified PAL SNES.
     
    Last edited: Feb 10, 2014
  7. sanni

    sanni Intrepid Member

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    It might be possible that you got a 75Ohm resistor in the sync line. Most Pal RGB cables have them. Use a multimeter to messure if thats the case and then remove it. On my TV the picture is constantly rolling with the resistor still in place. I use a Super Famicom with my European TV.

    One other thing you could try is to manually set your TV to PAL or NTSC. On my Panasonic I can choose between Auto/PAL/NTSC and with a 50Hz modded Super Famicom I have to manually set it or else the picture will be shifted to the left. Maybe that would help your TV too.
    Technically if you got a 2 PPU SNES you are outputting 50Hz NTSC when you put it in 50Hz mode. Not all TV's can cope with that. A 1-chip SNES however can be modded to always output the right video signal.
     
  8. p4r4d0x86

    p4r4d0x86 Member

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    Ok, I will have a look. I see a resistor in SNES connector between PIN 9 and another PIN but not in serie on the composite sync. I will test with multimeter.

    I think you forgot something in my first post :p I am not outputing NTSC or PAL, I am outputing RGB at 50Hz or 60Hz ;-)
    But I agree with you, not all TV's can accept NTSC 50Hz. I tested yesterday composite output : NTSC 60Hz => I got color, NTSC 50Hz => black & white with the sync problem.

    I have a more precise look at the problem. It's really a problem of sync. When I have the problem, block of lines are slayed of ~20 pixels to the left.
    Interference with the 50Hz of sector ? Problem occurs every 5 or 10 seconds or sometimes twice in one second but regularely. I really think it is a problem internal to the snes (voltage on sync signal ?) ... but will test the cable for resistor first ;-)
     
  9. p4r4d0x86

    p4r4d0x86 Member

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    I found something interesting on another forum :
    http://www.boards.ie/vbulletin/showthread.php?t=2056593395

     
  10. p4r4d0x86

    p4r4d0x86 Member

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    Last edited: Feb 11, 2014
  11. Lum

    Lum Officer at Arms

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  12. p4r4d0x86

    p4r4d0x86 Member

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    No, I just discover this kind of problem : pure sync VS sync with video, LM1881 solution, put sync of S-video in place of composite sync ...
    Now I have the right keywords to implement a solution
    I will try and come back to give a feedback

    Thanks for helping me ! :)
     
  13. p4r4d0x86

    p4r4d0x86 Member

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  14. Lum

    Lum Officer at Arms

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    Sounds promising. I don't mod though.
     
  15. p4r4d0x86

    p4r4d0x86 Member

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    It perfectly works !

    Thanks everybody for help :)
     
  16. Myria

    Myria Peppy Member

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    I compensated for the NTSC SNES's +1V DC bias mentioned on that page by setting the RGB resistance on my XRGB-3 to 225 Ohms instead of 75 Ohms. Should I be soldering 220μF electrolytic caps inside the SNES instead? (I don't want to modify the European GameCube SCART cable or the SCART-to-RGB21 adapter, because I intend to use those cables on a Famicom 2 with that Australian guy Tim's RGB mod as well.)
     
  17. MangledLeg

    MangledLeg Peppy Member

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    I always figured those games got cranky when shifting outside of their native refresh rate due to optimisations in the code? I noticed the same with pushing my PAL carts of the above into 60hz, and remember similar issues crop up in many other games. On the Mega Drive I recall multiple games from Ancient that crap out if you adjust the refresh rate in-game, and in Sonic 3D on the Saturn if you push the PAL version to 60hz the 3D geometry disappears in the bonus stages.

    Before hacking more stuff apart, I'd suggest trying some games that are happy to float between refresh rates on your SNES. From memory, PAL Super Metroid behaved itself but I'm a bit rusty on my other PAL titles!

    Mind, if your hacking job worked you can disregard all the above :)
     

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