What's currently the best RGB mod for the PC Engine?

Discussion in 'Modding and Hacking - Consoles and Electronics' started by FireAza, Apr 17, 2013.

  1. RetroSwim

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

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    :)

    It's a good thread, heaps of good information in here. I've definitely got it bookmarked for future reference.
     
  2. Fandangos

    Fandangos <B>Site Supporter 2013</B>

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    In the end which circuit did you use?
     
  3. RetroSwim

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

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    Um:

    ;)
     
  4. existensmaximum

    existensmaximum Member

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    Did you amplify the c-sync in the end, or did you just use it as-is?
     
  5. bacteria

    bacteria I am the Bacman

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    One option is to get a TurboGrafx instead of PC Engine as it has a graphics chip you can tap off RGB directly.
     
  6. earthshaker

    earthshaker Member

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    Hello guys! I just tried to mod my pce but it doesn't work. I followed your thread and you mods ( but i am using an 8 din pin socket instead of a 9 pin, as mmmonkey's guide) ><
    i followed this pic to wire the pin socket:
    [​IMG]
    I have some question..
    1) In the idiot's schematic the three 5.1 ohm resistors are wired to the ground, instead in the schematic on the first thred page, are connected to VCC (i guess).
    2) Shouldn't I connect 5 volt to the 8 pin din socket? the idiot's schematic doesn't connect it.
    Thank you for your patience and your help!
     
  7. relo999

    relo999 Robust Member

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    I just did the mod, worked great until I closed it up. Now it doesnt show any video, what might be the problem?

    Edit: found the problem, chip got loose
     
    Last edited: Apr 6, 2014
  8. Friend of Sonic

    Friend of Sonic Spirited Member

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    I ordered a PC Engine Core that was promised to have no jail bars, but they're just as bad as the Turbo Grafx I had modded. Any ideas to get rid of the jail bars? I've heard installing a couple of ceramic caps at certain points, and also adding an amp to my SCART cable.
     
  9. ApolloBoy

    ApolloBoy Gutsy Member

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    Except the European TurboGrafx runs at 50 Hz.
     
    Last edited: Apr 6, 2014
  10. APE

    APE Site Supporter 2015

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    Put one of these together for a CoreGrafx console and it almost works great but after a few seconds of booting the thing up the picture slowly fades to black. I'm following the aforementioned circuit exactly which leaves me confused. I'd rather not put together a discrete transistor based amp but I'm running out of options.
     
  11. ApolloBoy

    ApolloBoy Gutsy Member

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    Where are you getting 5V and ground?
     
  12. APE

    APE Site Supporter 2015

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    Wherever I can source it on the board. The 5v for the amp is being sourced from a point close to the 7805's output pin.
     
  13. ApolloBoy

    ApolloBoy Gutsy Member

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    Can you post a picture of how you have it wired up? I've done this on a Core Grafx II which is pretty much the same and never had any issues.
     
  14. APE

    APE Site Supporter 2015

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    I'm going to put aside the amp I'm using and rewire it to start with just in case I've got a bad amp or cap. Right now it's wired up identically to the earlier schematic you posted sans an additional decoupling capacitor.
     
  15. Bad_Ad84

    Bad_Ad84 The Tick

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    Any caps in the cable? (assuming you are using scart and then a converter? - if not, disregard)

    Also, are you 100% sure the caps are the correct value on the output?
     
    Last edited: Jun 11, 2014
  16. APE

    APE Site Supporter 2015

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    100% sure? Nope. The cable has 220uF caps on the RGB lines and I tried using a 220uF on the amp's RGB output lines and without; didn't see a difference.

    I'm also using straight composite video fed into the external sync input on my PVM. Originally the cable had some sort of "sync booster" (I can't find a datasheet for the chip inside) but I've since bypassed it.
     
    Last edited: Jun 12, 2014
  17. Bad_Ad84

    Bad_Ad84 The Tick

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    IIRC, you shouldnt have caps in the cable. The signal from the amp is exactly what should go to the TV.
     
  18. APE

    APE Site Supporter 2015

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    Removed it and I don't see a difference. Even built a second circuit using different components and it acts the same way.

    EDIT:

    Just tried a C945 as an amp with no other components attached: almost instant fade to black. Wire up the cap back into the cable and the picture is extremely red (that isn't part of the picture that the CoreGrafx is outputting, it's like a filter across the entire screen) that fades to normal then to black slowly.

    Could it be possible that the CoreGrafx has an issue that other consoles of this lineage don't have?
     
    Last edited: Jun 12, 2014
  19. Zer0-2k11

    Zer0-2k11 Site Supporter 2012,2013,2014,2015

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    It could be that its a grounding issue. Have you tried different ground spots?.
     
    Last edited: Jun 13, 2014
  20. Ergot_Cholera

    Ergot_Cholera Flaccid Member

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    I have performed this mod but the image looks a bit off, slightly washed out and there are some faint vertical lines. I don't think they are jailbars as they seem uneven in width. I used 5M1 resistors and 0.1 uf caps on the input and 220 uf caps and 75R resistors on the output. The decoupling cap is 22uf with a 0.1uf across it.
    [​IMG][​IMG][​IMG][​IMG]
     

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