Thursday, June 1, 2023

Totally unauthorized transcript: HD15-2-SCART: RGBHV & RGBs to SCART

Note: This is the first of possibly many transcripts I do for both fun and necessity (never just one or the other). I kept referring to the video linked below because I really had to make sure I wasn't going to wreck my expensive gscartsw and gcompsw with my supergun. 

Right now, I made new line breaks whenever I felt a natural break. Otherwise, I'd go every 30 or 40 seconds. Ultimately though, I'd like to turn this into something like a CCSL, just without frames. Hopefully it'll still look good in this Blogger template.


HD15-2-SCART: RGBHV & RGBs to SCART (by RetroRGB)

YouTube: https://www.youtube.com/watch?v=ifb9YBIHMpU

Purchase: https://castlemaniagames.com/products/rondo-products-hd15-2-scart

 

[00:00:00]

BOB:  A new device was just released that solves one very annoying problem that retro gamers often run into: how to connect consoles that output via a VGA-style D-sub connector to devices that have SCART inputs.

 

[00:00:00]

BOB:  Some of the most helpful tools aren't always the flashiest, but I love them just as much as the rest.  So, let's take a look at the HD15-2-SCART adapter. 

 

[00:00:22]

[intro sequence]

 

[00:00:36]

TEXT:

RetroRGB

HD15-2-SCART: RGBHV to RGBs Converter

 

[00:00:38]

BOB:  Before we get into the video, I just want to make the point that this device does not change the resolution of the signal being fed through it.  This isn't a downscaler that converts VGA to RGB; this is simply a device that passes the RGB signals from a D-sub connector through to SCART with a switchable option to combine H&V sync into Csync.

 

[00:00:46]

TEXT:

*THE HD15-2-SCART adapters shown in this video are prototypes - Production versions will look slightly different.

 

[00:00:56]

BOB:  That's still a really necessary tool in most people's retro gaming setups, but I wanted to set expectations straight.  Okay, let's start with a quick overview of how it works. 

 

[00:01:08]

BOB:  This is a device designed by Tian Feng that's part connector adapter, part sync combiner.  To start, the RGB and ground signals are passed directly through the D-sub connector without any conversion at all.  Then, a 3.5mm jack allows audio to be routed, and all of those signals are passed directly to the SCART output, converting the connector from D-sub to SCART.  The only circuit in the adapter, and what sets this apart from other connector converters, is the sync combiner and sync attenuation.

 

[00:01:33]

TEXT:

*Once again, this is a prototype that I hand-soldered.  Production versions will look MUCH cleaner than this!

 

[00:01:40]

BOB:  When set to VGA mode, the horizontal and vertical sync signals are combined via an XNOR circuit originally designed by Ste from HD Retrovision.  This allows things like a Dreamcast's VGA cable to be used on a RetroTink 5X.  The next setting is RGBs mode, which passes the sync through a resistor that drops it to a voltage safe enough to be used with devices like the MiSTer's I/O board on SCART equipment. 

 

[00:02:06]

BOB:  Also, for cost reasons, this is a unidirectional device.  It only works as a D-sub-to-SCART adapter, not the other way around.  We are working on a device that goes in the reverse direction, but more on that later.  Okay, let's check out some examples of this thing in action. 

 

[00:02:23]

BOB:  I think one of the main uses for this device is connecting 480p VGA signals to SCART devices that can handle the higher-resolution signal.  The RetroTink 5X is a perfect example.  It doesn't have any VGA inputs, but has no problem accepting 480p signals. 

 

[00:02:39]

TEXT:

*Safe voltage can only be guaranteed if purchased from reputable sellers, or if the EXACT design and BOM are used - if you change a component, the voltage can change. 

 

[00:02:39]

BOB:  This device passes RGB right through, then combines sync into a level that's perfectly safe for all SCART devices.  The creator of the Tink 5X, Mike Chi, also confirmed it's safe, and should work fine with TV resolutions.  PC resolutions may not work on the Tink 5X, but should be safe to try.

 

[00:02:56]

TEXT:

*Looks like the Virtual Tap's 800x600 output isn't compatible with the current RetroTINK 5x firmware.

 

[00:03:00]

BOB:  Another great example are multiformat CRTs, as most only accept component video or RGBs.  Using this device will convert RGBHV to a voltage-compatible RGBs that'll also work with pretty much all PVMs and some BVMs.  As with the Tink 5X, resolution still matters, so make sure your source device is sending a compatible resolution to your target display.

 

[00:03:23]

TEXT:

*Some monitors like the H-series BVM's require special, powered sync circuits

 

[00:03:28]

BOB:  And speaking of compatibility, the HD15-2-SCART is designed specifically for retro gaming equipment.  That means if you're using PAL consumer-grade CRTs, this most likely won't work, as it doesn't have voltage connected for the blanking pin.

 

[00:03:39]

TEXT:

*I don't believe any supported 480p through RGB SCART either.

 

[00:03:39]

BOB:  This is an open-source project, so people can feel free to make a version specifically for PAL CRTs, but this one's probably not gonna work.  They will work on HDMI-to-VGA converters, though.  Once again, you need to set your source to a resolution that's compatible with your target device, but you could use this for interfacing PCs to your multi-sync monitor, or even connecting your HDMI console to the Tink 5X's SCART input for downscaling.  In fact, I used this to get most of the downscaling footage in the RetroTink 5X launch video. 

 

[00:03:42]

TEXT:

*I used this RGBHV to RGBs sync combiner, as well as an HDMI to Component adapter for the downscaling testing / footage.

 

[00:04:15]

BOB:  Depending on your setup, HDMI to component might be a better choice.  But if you need RGBs, this is a great solution.

 

[00:04:24]

BOB:  Here's one more interesting use for this device in VGA mode: the OSSC.  Wait, what?  Why would anyone use this when the OSSC already has a VGA input?  Good question. 

 

[00:04:24]

BOB:  And the reason is the OSSC's low-pass filter is only connected to the SCART and component video inputs, not the VGA.  Sometimes this won't matter, but other times it could clean up a lot of interference.  Here, check out the screen when a device is connected directly to the VGA input.  Even though the OSSC says the low-pass filter's on, it's not affecting the VGA port at all. 

 

[00:05:01]

BOB:  Now let's take a look through the SCART port.  As you could see, the low-pass filter makes a big difference. 

 

[00:05:07]

BOB:  Depending on your source device, it might really benefit from sending it through the OSSC's SCART port instead of the VGA. 

 

[00:05:16]

BOB:  The HD15-2-SCART isn't just for VGA-style signals, though.  There's actually plenty of equipment in the retro gaming world that outputs RGBs over a D-sub style connector.  And the most common one these days?  The MiSTer.  That's right, with this device, you could just use a cheap shielded VGA cable, and have an easy way to interface the MiSTer to SCART equipment.  And it's perfectly safe.  Something that can't be said for other supposed MiSTer SCART cables.  Here's why. 

 

[00:05:46]

BOB:  The Mister's analog I/O board was designed to be as versatile as possible.  It could output RGB, VGA, and component video all through the same D-Ssub Connector.  One downside of this, though, is the sync output needs to be TTL-level voltage. 

 

[00:05:58]

TEXT:

1.1v under 75ohm load, is just too high for SCART equipment.

 

[00:06:02]

BOB:  If you're just going into an RGB monitor, that should be fine.  Make sure to check your monitor's service manual to be safe, of course, but while it should be fine for most RGB monitors, that voltage is much too high for SCART equipment.  This attenuates that voltage to a level that's perfectly safe for all devices, including all PVMs and SCART equipment.  I'll definitely be using this from now on with my MiSTer, just because I don't have to worry about anything.  As long as I grab one of these and a VGA cable, there's no safety issue.  Whereas if I grab a VGA-to-SCART cable, I'm gonna have to check to see if it's a passthrough cable, or if there's one with a resistor in it. 

 

[00:06:03]

TEXT:

*MiSTer -> VGA to BNC Cable -> RGB Monitor is probably safe, but you'll need to check your monitor's specs to be sure.

 

[00:06:39]

BOB:  Now, there are reputable stores selling MiSTer-compatible SCART cables that include the resistor on the sync line, but some stores don't include it.

 

[00:06:39]

TEXT:

*This is just one of many good "MiSTer SCART cable" sellers.

 

[00:06:48]

BOB:  That's right, there's sellers out there labeling their passthrough cables as safe-for-use with the MiSTER, even though there's no resistor in them. 

 

[00:06:52]

TEXT:

There's no resistor on the sync line - This is NOT safe for use with the MiSTer and SCART equipment!

 

[00:06:57]

BOB:  Now, if you want to be safe, you could test a MiSTer SCART cable without opening it at all by using a multimeter.  Or simply by popping the SCART head open and looking for a resistor. 

 

[00:06:56]

TEXT:

*Check out my video on how to test cable components for an easy way to check if there's a resistor on the sync line.

 

[00:07:05]

BOB:  I'd personally not worry about it at all and just use one of these, but that's totally up to you.  If you already own a MiSTer cable, definitely pop it open or test to check if there's a resistor in it, though. 

 

[00:07:16]

BOB:  Oh, and this will also work with the MiSTer's HDMI direct modes via an HDMI-to-VGA converter like shown before.  That's a great way for MiSTer users without an I/O board to get lag-free 1:1 RGB output.  Just follow the instructions on RetroRGB to configure your .ini file, and you'll end up with an RGBs signal that's properly attenuated for your SCART equipment. 

 

[00:07:41]

BOB:  There is one small downside to the attenuation, though.  Some custom RGB mods with D-sub outputs might have voltage that's too low.  There's not much of a chance of this happening, but if you have a custom setup with a bunch of crazy adapters and this doesn't work for you, you'll need to recheck your setup.

 

[00:07:41]

TEXT:

LOL, there's no reason to do this.  Just showing an example of one of the RARE times you might have an issue...

 

[00:07:59]

BOB:  The best part is, there's no safety issue.  As long as you're using properly built consoles and superguns, the worst thing that could happen is nothing.  You just don't get a sync signal. 

 

[00:08:09]

BOB:  And, speaking of superguns, they're the next most likely place you'll run into a D-sub connector passing RGBs.  Here's the Axunworks JAMMA Supergun Mini.  And, like the MiSTer, it's usually safe to connect it directly to most RGB monitors, but not safe to directly connect it to SCART equipment. 

 

[00:08:28]

BOB:  Using this device drops sync to a perfectly safe voltage, and is an awesome way to connect the supergun to your display. 

 

[00:08:29]

TEXT:

When using the HD15-2-SCART, the voltage is now down to a perfectly safe level. 

 

[00:08:36]

BOB:  Just a quick note.  Like with all superguns, don't crank the RGB levels too high, or that could be a voltage concern.  That has nothing to do with this device or the Axunworks Mini.  It's just a general supergun reminder. 

 

[00:08:51]

BOB:  One last thing before I go.  Since this is a unidirectional device, we're also working on one that goes in the opposite direction: SCART to D-sub and audio.  Now, I don't think there's any need for a circuit in that one, just a passthrough, as there shouldn't be any safety issues.  And while I don't think it's gonna be nearly as popular as this, there are a few ways that I think people would benefit from it.  Let me show a few examples. 

 

[00:09:13]

BOB:  First, if you have a SCART switch, you could use this along with a cheap VGA-to-BNC cable to send video to your monitor. 

 

[00:09:13]

TEXT:

*SCART-2-HD15 prototype shown - The final design will most likely be different. 

 

[00:09:21]

BOB:  Depending on your setup, just buying a SCART-to-BNC cable might be a better option.  But this option's here if you need it. 

 

[00:09:28]

BOB:  Next, maybe you just want to use a VGA cable to go from your switch to your SCART device.  I mean, it's always best to keep your analog cables as short as possible, but sometimes that's just not an option.

 

[00:09:28]

TEXT:

*Once again, this is a prototype.  I'll update the description once the final version is released.

 

[00:09:40]

BOB:  In that scenario, it might be cheaper to get both of these adapters and a long, shielded VGA cable as opposed to buying a long, shielded SCART cable.

 

[00:09:50]

BOB:  Now, to be honest, I'm not even sure if the SCART-2-HD15 is gonna be released as a product for sale, or just as an open-source product that people can make themselves.  But either way, keep your eyes on RetroRGB.com, 'cause as soon as there's more info, I'll definitely post there. 

 

[00:10:05]

BOB:  So to sum things up, if you have any D-sub equipment in your setup, including and especially the MiSTer, I'd definitely recommend buying one of these.  Now of course, if you already have a fully-wired setup that's running perfectly, you don't need to switch any of that out for this.  But on the other hand, if you're a nerd like me that always likes good tools in your toolbox, this is also something you should seriously consider. 

 

[00:10:29]

BOB:  Since this is an open-source project, you could feel free to make your own.  But it is not an easy installation.  That is a really small circuit on there, and I had a hard time with at least one of those parts.  Luckily, Greg from Laser Bear designed the case, as well as a jig that makes things easier when you're soldering the SCART connector onto the circuit board.  So that's available if you could 3D print your own.  But it's still not something I would call an easy install. 

 

[00:10:56]

BOB:  Well, that's it for this time.  Please consider supporting this channel, as all the work I'm involved in is funded directly by the retro gaming community through monthly or direct support services.  Your help is keeping all of this stuff and the weekly podcast live.  Thanks very much, and I'll see you next time. 

 

[end of file: HD15-2-SCART: RGBHV & RGBs to SCART]

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