Pc Engine NTSC / Turbografx PAL NO SYNC at all?

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    Hi all,

    New OSSC owner here, im hoping someone may be able to help me.
    All my other consoles work brilliantly except my NTSC PC Engine and PAL Turbografx.

    When I connect either of them using either adapter, nothing is displayed on the OSSC screen at all (NO SYNC) as if there is nothing connected.

    I am using a Sega MD2 CSYNC packapunch cable through with 2 different devices on the expansion port.

    I have a couple of different versions:

    An older version of this: (without the TTL/75ohm switch)

    dbGrafx Booster

    And one of these:


    Neither seems to want to activate the OSSC, however they both work fine connected directly to a scart TV, or via a cheap and cherful scart to HDMI adapter I used prior to purchasing the OSSC.

    Any help appreciated!

    Thanks in advance.


    Are you using a scart switch? Searching the forum, seems that the GSCART switch can cause issues.

    Bucko posted that “some adjustments” were needed on the OSSC, but he didn’t specify in that particular thread. There is also nothing on the wiki.

    I’m assuming this is a sync issue, so you can start to try adjusting the sync LFP or sync threshold settings.

    Also see this thread: https://videogameperfection.com/forums/topic/turbografx-sync-issue/


    Hi Harrumph,

    Thanks for the reply, I do have a scart switch, but I have also tried both consoles and devices connected directly to the OSSC.

    I will have a look at the LFP and threshold as suggested and see if it make a difference.




    I managed to get it working, it turns out the db-grafx booster doesnt actually work on my normal TV after all, s-video and composite from it are fine, but the RGB output briefly displays a picture then fades to black on both the NTSC and PAL consoles.

    The cheapie ebay one works perfectly on the TV and with the cheapie scart to HDMI.

    I wired up the cheapie to the OSSC directly and it then just worked, I made sure LPF was set to max.
    I tested through the scart switch I have and its still good, the only time it doesnt work is if i have 2 scart switchers in series but i guess thats good old fashioned signal degredation going on.

    The sync is definitely better using the packapunch cable rather than the standard cable, so i will continue to use this setup and ditch the db-booster (even though it was more pricey!).

    Thanks for the heads up, and hopefully the info will help someone else.


    That fading to black problem sounds like bad/unnecessary capacitors in your RGB cable.

    Try the following settings if you have further issues. Analog Sync Vth to 101mV or higher and the Vsync Threshold to around 11.38.

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