OSSC to PC VGA CRT – Unstable signal on Line2x (fw v0.88)

[Apasher]

Hello. I am a recent OSSC owner and wanted to try out hooking it up to my PC CRT (ViewSonic A70f). On Line3x and above, I get a stable image. However on Line2x my monitor would badly flicker on and off. Even after dialing in phase, it didn’t stop the flickering. Is there any way to fix this issue, or do I have to write it off as the monitor not being compatible on Line2x mode?

I should also note that my source is an NTSC N64 running S-Video through the Koryuu transcoded to YPbPr. Here is a twitter video clip of me running Ocarina of Time with my PC CRT and my BenQ Zowie RL2455 side-by-side. I’ve noticed that I don’t get flickering until I either pause the game, or I open the OSSC menu.

I could just use Line3x, but the problem is my capture card (Avermedia Live Gamer HD 2) doesn’t support anything over Line2x.

[BuckoA51]

What DAC are you using with the CRT?

[Apasher]

I’m using the Tendak HDMI to VGA DAC

UPDATE: Changing the TX mode to HDMI (YCbCr444) has given me a more stable image on my PC CRT using Line2x mode! I still get the occasional dropout, but it doesn’t happen anywhere near as often. I think on that note it might be a problem with either my DAC or the CRT itself, because I notice it happening with the RetroTink2x-M every now and then.

[BuckoA51]

Indeed, we really need someone in the community to come up with a consistently good quality DAC, especially now HD Fury have discontinued the Nano.

[TyMiles2012]

I also have the Tendak with the same issue. I’m pretty certain the DAC is the problem now since now I know I’m not the only one and I use a different CRT (Gateway EV910). From what I’ve tested, it seems to be an issue with horizontal resolution, and potentially the brightness of the image. Line2x with a 240p console is very unstable, the Wii which has a 720px wide buffer rather than 640px is more stable (I get either sync drops or rapid red/blue pixels speckling on the screen), a super resolution on my PC (I use 2560×400 to play DOSBox) is perfectly stable whereas a custom 640×400 is basically unusable.

Also, try setting TX mode to DVI (Unless you absolutely need HDMI audio). At least on Wii, that’s as stable as it gets where I just get a sync flicker once every so often rather than a dropout.

EDIT: I had another DAC sent to me today, and so far it’s been WAY more stable. It’s an active one by JideTech, you can find it on Amazon for under $40. Colors seem to be the same. It doesn’t rescale the output either, even a custom 320×240 120hz resolution works! The only issue I’ve had is that when you set TX mode to DVI, it has a large flickering black bar slowly scrolling up, but setting it to HDMI RGB or YCbCr444 resolves it, which is weird because it worked with my GCVideo modded Gamecube with no issue. So far it’s worked on my OSSC at 640×480 and Wii (720×480), including my PC at 640×400 and even the 320×240 at 120hz I’ve mentioned before.

[BuckoA51]

The big problem seems to be inconsistency here. Earlier Tendak’s were raved about by the community, perhaps at some point they changed the chipset or something.

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