Proper TG16 RGB output that works with OSSC and gscartsw

[nintari]

Well... after lurking for so long and running in to a road block.. I had to sign up and ask a question....

Previously I had all my consoles hooked up via several daisy chained Extron MPS 112 switches and manually hooked up RGB scart to either a scart to YPrPb converter for my CRT, or to my OSSC for the 4k set or projector.

Since I was far enough along on my setup I thought it a good time to purchase a gscartsw, better scart cables (all shielded) and get away from the extron as much as possible (I still use one for unmodded consoles that I do not play too much or cant be modded easily)

One of the systems in my setup (as the topic states) is a TurboGrafx 16, for which I was using a cheapie chinese AV booster / RGB board that connects to the ext port on the TG16. I know many on here will instantly jump all over the Chinese adapter but, please refrain from such actions for now. This worked fine in conjunction with a cheap Genesis model 2 (or MD2) cable to my CRT, and worked on the OSSC as long as I turned the sync tolerance up and the LPF to max. With a better grade cable...the scart to YPrPb converter works... but the OSSC doesn't detect sync. To finish this off... neither cable works at all through the gscartsw, and the better cable doesnt on the YPrPb converter or ossc.

I do want to look in to doing this properly...but it also seems this is a common issue with the gscartsw and the turbografx and pc engine. So what is the proper / best way to get this working? I have no issues or fears when it comes to some electronics work (although I am extremely rusty with a scope...speaking of which I'd have to see if my scope even still works lol it's been sitting in a garage for 15 years)

I also am a bit confused on which sync is better for the TG16. It seems as if the better cable was pulling sync from the sync pin on the EXT connector to pin 5 on the MD2 end to pin 20 on the scart connector with a cap and resistor in line, Where the cheaper cable was using composite video (pin 4 on the MD2 connector) to pin 20 on the scart connector with no components inline


The Chinese RGB board looks to be using a THS7314 only on RGB and it does not appear as if there are any other ICs /components boosting or altering sync. There are a few resistors and etc here and there but nothing that I believe would alter sync (tried toning out the circuit to follow the paths they take). This does have a switch for when using the RCA plugs to attenuate the RGB, but when using scart I do have the switch in to the MD2 position which is bypassing these resistors.

[nintari]

Also wondering on this as someone local to me has a PC Duo that has been region modded and RGB modded not to mention recapped available for sale lol...and if this has similar issues through the gscart and ossc... that would be a bit upsetting (of course I don't know what mod was done to it and what the quality of work is)

[it290]

I can't speak to your specific setup, but I will say that I've had no problems with either my stock PCE + SSD3's RGB SCART output or with my modded Duo-R using a retrogamingcables.uk cable into the OSSC.

[nintari]

No gscartsw in line then?

[it290]

Nope, not in my setup. It sounds like sync is getting degraded somewhere in your chain, though. Have you tried hooking up another console (a Genesis/MD2) to isolate the problem to the cables vs. the console side? I'm guessing it has more to do with the cables.

[thebigcheese]

There are a couple options. Tim Worthington makes the AV Driver that will give you RGB out with properly amplified audio and sync, but I find the resulting image to be a little soft. I think Mobius Strip Tech started offering an audio amp for the TG16 now, so you could use Voultar's PCE RGB amp in conjunction with that to get proper output. And if you don't want to do any modding, you could try to find a dbGrafx Booster or buy an SSDS3. I can say that both the AV Driver and the PCE kit offered by Console5 have worked perfectly with my Gscartsw and OSSC.

[ldeveraux]

Does the TG16>SCART>OSSC work without the gscartsw in line? If so, and your setup is like mine, that's the reason I returned my gscartsw.

[thebigcheese]

Does the TG16>SCART>OSSC work without the gscartsw in line? If so, and your setup is like mine, that's the reason I returned my gscartsw.

Don't think I ever tried it that way, but I've never had any issues. My friend bought the TG16 off me and I swapped it to sync on composite since he's not an RGB person, so I don't have a way of testing it now.

[ldeveraux]

Does the TG16>SCART>OSSC work without the gscartsw in line? If so, and your setup is like mine, that's the reason I returned my gscartsw.

Don't think I ever tried it that way, but I've never had any issues. My friend bought the TG16 off me and I swapped it to sync on composite since he's not an RGB person, so I don't have a way of testing it now.

My question was for OP

[thebigcheese]

LOL I even looked and thought you were the OP for some reason... still not quite awake.

[nintari]

Does the TG16>SCART>OSSC work without the gscartsw in line? If so, and your setup is like mine, that's the reason I returned my gscartsw.

with one cable, yes, the other, no. neither cable works through the gscart... but either way thats one of the questions I was trying to figure out was which sync is correct / better... and should there be any components in line on the sync line (pin 44 i think)?

just toned out the cheap cable and it looks like pin 4 on the MD2 side composite video is going to pin 20 for sync on the scart.
the "better" cable is pulling from pin 5 on the MD2 end (which is toned out to pin 44 on the TG16 port) going to pin 20 on the scart cable for sync. This has a cap 220uf 10v cap then a resistor measuring 2.1M ohms (dont have my glasses handy to verify the color bands on it)

[Johnpv]

I have a PCE Duo that is modded with Voultar's RGB Board and it works perfectly through my gscartsw. I believe it is using composite video for the sync as the CSYNC set up was not done for it. That said though it looks and works great, and I have no issues with it going through my gscartsw. For that one I use the RGB cable from Retrogamingcables.co.uk.

[nintari]

I have a PCE Duo that is modded with Voultar's RGB Board and it works perfectly through my gscartsw. I believe it is using composite video for the sync as the CSYNC set up was not done for it. That said though it looks and works great, and I have no issues with it going through my gscartsw. For that one I use the RGB cable from Retrogamingcables.co.uk.

do you know if there are any components inline on the composite video being used for sync on your scart cable? I plan on breaking out the soldering iron this weekend to RGB mod my CRT and may try a few tings out on my cables.

[thebigcheese]

If you're using composite video for sync, there shouldn't be any components in the cable. That's my preferred sync for these consoles.

[ldeveraux]

I have a PCE Duo that is modded with Voultar's RGB Board and it works perfectly through my gscartsw. I believe it is using composite video for the sync as the CSYNC set up was not done for it. That said though it looks and works great, and I have no issues with it going through my gscartsw. For that one I use the RGB cable from Retrogamingcables.co.uk.

I have the same board on a US TG-16 but SCART cable from retro-access.com. It didn't work at all through the gscartsw and superg blamed it on "non compliant signal and shitty mods" so food for thought.

[nintari]

I'm going through looking at various RGB mods out there trying to determine what "should" be used to get proper sync and make any necessary modifications. I have the luck of working at a TV station....and although we moved to HD and digital for the most part I refused to throw out any of the old ICs and parts / switches etc etc lol.

[Johnpv]

I have a PCE Duo that is modded with Voultar's RGB Board and it works perfectly through my gscartsw. I believe it is using composite video for the sync as the CSYNC set up was not done for it. That said though it looks and works great, and I have no issues with it going through my gscartsw. For that one I use the RGB cable from Retrogamingcables.co.uk.

do you know if there are any components inline on the composite video being used for sync on your scart cable? I plan on breaking out the soldering iron this weekend to RGB mod my CRT and may try a few tings out on my cables.

I would think not since its just composite video. Though you could probably email or tweet at retrogamingcables to be sure.

I have a PCE Duo that is modded with Voultar's RGB Board and it works perfectly through my gscartsw. I believe it is using composite video for the sync as the CSYNC set up was not done for it. That said though it looks and works great, and I have no issues with it going through my gscartsw. For that one I use the RGB cable from Retrogamingcables.co.uk.

I have the same board on a US TG-16 but SCART cable from retro-access.com. It didn't work at all through the gscartsw and superg blamed it on "non compliant signal and shitty mods" so food for thought.

It doesn't sound like food for thought. Did you have the mod work checked of who ever installed it?

Voultar's board is great and definitely puts out a compliant signal. If anyone's board does its definitely his, he's super anal about that.

[ldeveraux]

I have the same board on a US TG-16 but SCART cable from retro-access.com. It didn't work at all through the gscartsw and superg blamed it on "non compliant signal and shitty mods" so food for thought.

It doesn't sound like food for thought. Did you have the mod work checked of who ever installed it?

Voultar's board is great and definitely puts out a compliant signal. If anyone's board does its definitely his, he's super anal about that.

I have the same board installed but I get no signal through that particular switch. Works fine through other switches and direct to OSSC, I'm not smart enough to understand why it wouldn't work universally. I think the board is fine, that was my point.

[nintari]

For now until I can test this further and find a mod that will work properly....

I plan to mod my CRT tonight or this weekend to take RGB Scart in and will be bypassing the scart to component adapter I currently use. This would then free up that adapter and allow me to use it on the TG16 in the mean time, and I'll just put it on my extron MPS 112 with the other component based systems.

This could potentially be small variations in the different releases of the gscartsw that handle the TG16 sync differently, or the other way around, enough variation in the TG16s that some output cleaner sync than others. Perhaps a re-cap may be in order to see if that helps to rectify the situation.

[Voultar]

I have a PCE Duo that is modded with Voultar's RGB Board and it works perfectly through my gscartsw. I believe it is using composite video for the sync as the CSYNC set up was not done for it. That said though it looks and works great, and I have no issues with it going through my gscartsw. For that one I use the RGB cable from Retrogamingcables.co.uk.

I have the same board on a US TG-16 but SCART cable from retro-access.com. It didn't work at all through the gscartsw and superg blamed it on "non compliant signal and shitty mods" so food for thought.

I don't own a GSCARTsw so I can't confirm. But if the GSCARTSw isn't getting along with my IFU-RGB or DuoRGB amplifiers, it's not because of a non-compliant or "poorly shaped" C-Sync output.

If that switcher can't trigger off of a buffered C-Sync signal with an amplitude that lives anywhere between 300mvPP and 650mvPP, there's something that's not right. As that's as standard as it gets.. Should be zero problem slicing that. Definitely needs to be looked into

The issue (if any exists) might be how the the GSCARTSw is actually triggering, though. PC-E C-sync off of the RAMDAC (6260) has unusual pulse-widths for both horizontal and vertical and they're slightly out of time. That might be enough to muck it up. But otherwise I haven't the faintest idea. It's either that or most likely some sort of logic threshold error on the switch.

[fernan1234]

In my experience cycling through various PCE mod solutions, forcing C-sync out of this system is not worth it as it can cause incompatibilities like this (most likely for the technical reasons Voultar mentioned). The safe approach is CVBS sync paired with good shielded cables.

[Bratwurst]

In my experience cycling through various PCE mod solutions, forcing C-sync out of this system is not worth it as it can cause incompatibilities like this (most likely for the technical reasons Voultar mentioned). The safe approach is CVBS sync paired with good shielded cables.

The composite video output of the TG16 is really quite good as-is, and it is what I ended up utilizing as sync with my own RGB-out box for simplicity's sake.

[nintari]

In my experience cycling through various PCE mod solutions, forcing C-sync out of this system is not worth it as it can cause incompatibilities like this (most likely for the technical reasons Voultar mentioned). The safe approach is CVBS sync paired with good shielded cables.

The composite video output of the TG16 is really quite good as-is, and it is what I ended up utilizing as sync with my own RGB-out box for simplicity's sake.

Makes sense since the "cheap cable" used composite video as sync and worked through my ossc...but the "better" cable using sync didnt work.
Now the question I suppose is.... should there be any components inline on the composite video as sync to smooth / correct it?

[thebigcheese]

No, you do not need any components inline when using composite video. Just make sure to use good quality cables so there's no crosstalk between the lines.