Dreamcast Flicker Issue – Fix

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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!


    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.


    Hi, first time running the DC through the OSSC, and I am having this flicker issue sometimes, usually with lighter colors and white. I want to try the couple of different settings above, but I’m not sure how to access the OSSC menus. FW is .73. Do I need a remote?




    Hey, I answered my own questions, it looks like I need a remote to do this. Fortunately I have a Logitech Harmony 650 that I programmed and was able to go through the menus.

    Sync Options -> H-PLL Post-Coast -> 1 lines

    did the trick. (was set at 0) No more flickering! The other suggestion referring to the 480p-in settings did not stop the flickering.

    Edit, thanks for the answer harrumph, I was typing this message while you answered and I did not see it until I posted.


    No problem 😉

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