Dreamcast Flicker Issue – Fix

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This topic contains 5 replies, has 5 voices, and was last updated by  shadowofbob 1 month ago.

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    Hi there. Just got my OSSC and I’m absolutely loving it. I had a flicker issue with my Dreamcast, running through a Kuro VGA box on a Sony XBR55X810C and recently discovered the fix. Thought it might help others having the same issue: Navigate to:

    Sync Options -> H-PLL Post-Coast -> 1 lines (really anything more than 0 lines seems to help)

    This solved the issue for me and my Dreamcast looks beautiful running through the OSSC now. Hopefully you guys find this useful!

    • This topic was modified 1 month, 3 weeks ago by  amstrick17.
    • This topic was modified 1 month, 3 weeks ago by  amstrick17.


    Really odd that you would need this setting for the Dreamcast though.



    Yeah I thought it was weird too, but adjusting that sync setting fixed my issue.



    H-PLL coast settings should not have any effect in RGBHV mode as coast is internally disabled.



    Heya fellas,
    I found that my Dreamcast would flicker on default settings until I changed the “480p in sampler” setting to “DTV 480p”.

    For some reason after that the flickering hasn’t occurred anymore.



    Just wanted to confirm that setting Sync Options -> H-PLL Post-Coast to 1 line also fixed the flicker issue with my Performance VGA box that I was seeing.

    Mentioned on this page in Shmups forums.

    Has anyone else has issues with RGBHV input and the Dreamcast? Not sure if something has started failing in my unit, but the other day I noticed that there is a random flicker/white level change happening with VGA input from my Dreamcast. Noticeable on primarily lighter colors, especially the boot sequence. None of the other inputs have this occur or even with RGBS over AV3. Tried swapping Dreamcast systems, power supplies for the OSSC and it still happens. Bypassing the OSSC doesn’t show this issues on my VGA monitor. I’m going to try another RGBHV source like my GCN or my Xbox 360 VGA cable tonight to see if it’s that or something weird with how my Dreamcast VGA box interacts with the OSSC.

    • This reply was modified 1 month ago by  shadowofbob.
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