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Get OSSC Pro Features On Your OSSC With This Simple Mod


Looking to breathe new life into your old Open Source Scan Converter? This official mod and firmware adds improved sync handling, improved picture quality, 6x line multiplying, improved compatibility with HDR displays, shadow masks and more!



…and if you’re here having done your homework on this mod and you just want to see how to do it and you’re not interested in all of the backstory and stuff because you’re already deep in the weeds in the world of the OSSC then I totally understand - I’ve added chapter markers to the video so you can skip straight to the relevant part.

But for everyone else like me who’s perhaps not quite so deep in the world of OSSC, if you stick around I’ll tell you the story behind what this mod actually is, what it aims to achieve, and why I think you should do it.

So the OSSC, or Open Source Scan Converter, is a device that probably needs no introduction if you’re into the worlds of vintage gaming / computing - it basically takes the signals from those old computers and consoles and line multiplies them, does some nice cleaning up of the signal and makes it look lovely on modern displays - and I’ve actually been involved with the testing of the OSSC Pro recently, and I’ve actually put out a couple of videos.

The second channel video I just had a look at the Atari ST, particularly its high resolution mode, and saw how well the OSSC Pro could handle that.

Spoiler alert - it was very good, a massive improvement on the other scalers that I have here, and I’ve done some testing with some PCs and stuff, seeing how it can keep up with changing resolutions and all sorts of things, and so far very limited testing but it has been a big improvement on the original Open Source Scan Converter.

But you don’t actually need to spend all of that money to upgrade to one of these to get some of its features because back in February 2023, Markus, who designed both of these devices, announced that he was actually doing a rewrite of the OSSC firmware - and that goes along with a hardware mod which basically bypasses the sync processing of the built in video chip and allows the FPGA chip to handle that which makes it a lot more flexible.

So up to that point the original hadn’t had any firmware updates since February 2022 and that was essentially just down to limitations of the hardware and taking it as far as it can get and it’s this hardware mod that actually allows all of this extra functionality to be added - which is fantastic!

In addition to some broader goals like improving sync handling across the board and reducing sync-related dropouts - which is always a good thing - as well as improving image quality, there have been further firmware updates over the past year that have added all sorts of interesting and exciting new functionality which I think is well worth checking out.

So there’s stuff like a new line6x multiplying mode, which will take your 240p or 288p signals from your old consoles, and 6x line multiply them all the way up to 1920x1440, which is a massive improvement.

There’s also support for the HDMI HDR flag - so if you have an HDR display and you’ve been seeing some weird brightness-related issues, then that should hopefully fix those.

It should be noted that this doesn’t add proper full blown HDR support to the original OSSC but does improve compatibility with some of those displays - particularly if you’re using scanlines.

One particular standout feature is the new shadow mask preset support - so in addition to the scanlines that the OSSC has always been able to do, you can now actually add shadow masks so you can emulate stuff like those old Sony Trinitron TVs and stuff like that for a more authentic looking picture - and the feedback on this firmware has been really good over the past year or so over on the VideoGamePerfection forums.

People testing with Super Nintendos, Mega Drives, Atari Jaguars, arcade boards, Neo Geos, all kinds of stuff, and there’s all sorts of screenshots and things over there showing people’s results that you can go and have a look at.

So that’s the mod in a nutshell, and if that’s piqued your interest and you’re wanting to do this to your own OSSC, I’m going to show you how to do that right now.

So this is my OSSC that I’ve had for a few years now - it’s the 1.7 version from, and of course being open source there are a few different versions of this out there - a few different implementations of it - but by and large the internals should be the same - the outer casing is often quite different though, but in my case it’s very easy to get into, it’s just a case of removing the four screws on the bottom, and then we can get a closer look at the board.

So there are two steps to the actual hardware side of this modification, and the first step is to remove this resistor marked R35, which is in the very top corner of the board here - and it’s quite a simple process, but of course it is very tiny, it is a surface mount component, so just be careful - make sure you have a very fine tip on your soldering iron and try not to catch the resistor next to it.

Now the second step is a little bit more fiddly - so what you need to do is to take a short length of very fine wire and solder one end to the inner of the two pads from the resistor that you’ve just removed.

…and the other end of that wire needs to go to pin 25 of the TVP7002 video digitizer chip - so that’s the opposite corner to the resistor that you just removed and that’s right next to a component labeled C71.

…aaand that’s it! That’s literally it.

I told you there were only two steps, and you’ve probably spotted that I also re-routed that wire in a slightly more sensible way since I recorded that last clip, but this is what the modded board looks like, and now the only step that’s left is to install the updated firmware.

Updating the firmware is exactly the same as it’s always been, there’s no differences here, so I will link to the 1.x series firmware official download page down in the description, and all you need to do is grab whatever the highest version is with the .bin file extension, and then write that to an SD card as an image using something like Balena Etcher - and if you are using Etcher it will complain that there’s no partition table or whatever, but you can just safely ignore that and the update should proceed as planned.

So there we go, that’s my trusty old OSSC all modded up and ready to go - no longer stuck in 2022, which is absolutely fantastic - got all those new features on there. I have done a very quick test of this just on all of the inputs, just to make sure all the signals are syncing properly and stuff, and I’ve got that new line 6x multiplier mode, and that’s all working, which is great.

But that’s basically the limit of the testing that I’ve done with it so far. But yeah - so cool to have some of those OSSC Pro features for free! I mean you can’t really say fairer than that can you?

So if you found this guide useful why not give it a little thumbs up because that will definitely help my channel out and help to spread this guide a little bit further.

But thank you ever so much for watching, it’s great to have you, and I’ll hopefully see you in the next one!

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OSSC Pro Atari ST Test Video:
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Published on 11 Jun 2024 Post content: CC BY-SA 2.0 UK unless otherwise specified Get in touch!