S-Video Mod Schematic for the Schematic-Illiterate (For TG-16/Duo etc)

PCEngineHell · 09/13/2012, 04:37 PM

_{svideomodTG16DuoSupergrafxetc.png}

In similar fashion to the Sony CX one I did for my old crusty site.

You know, I wanted to point out, and this includes s-video mods regarding the Genesis, etc also, that even if your Tv DOES NOT support S-Video input, the mod is still worth doing. You can use a decent small S-video to Composite adapter like they sell online and at Radio Shack, and the picture quality from that Composite output will still be better then the native Composite output signal provided by the system in most cases. It still wont be as good as s-video, but the picture will still be a notch sharper, and the shimmering effect you see on sprites and objects during screen movement will still be reduced a noticeable amount. Just something to think about for all those stuck with Composite only input on CRT and LCD sets but who still desire improvement in picture quality.

(screen caps comparing composite and svideo on this mod can be found here:
https://www.pcengine-fx.com/forums/index.php?msg=280373)

Keep in mind, ymmv.

Drakon · 09/13/2012, 06:19 PM

No need to solder straight to the ic pin. I soldered to the surface mount resistor that the trace connects to you'll get a much bigger spot to solder with doing that.

PCEngineHell · 09/13/2012, 06:37 PM

Quote from: Drakon on 09/13/2012, 06:19 PMNo need to solder straight to the ic pin. I soldered to the surface mount resistor that the trace connects to you'll get a much bigger spot to solder with doing that.

Yeah I noticed too that between the Tg16 on that pin and on Pce Duo-R that the TG had a bit more/wider soldering area then the other system on pin 40 to attach to on that pin if you decide to solder there, so the pin spot on the TG-16 is easy to use. But in general, as long as you solder on something leading to that pin then it works. If I remember right too the Duo-R has a tiny solder blob leading off of a trace to pin 40 that is very close by, so you can solder on to that too if need be. If you don't have steady hands I'd def recommend finding a spot leading to the pin to attach to, or use a very fine point soldering iron.

Basically why I didn't bother posting any pic of any wires actually soldered to the pin directly, as the layout seems to vary some between systems. Everyone is just going to have to choose the spot leading to the pin that works best for them. Some people will want to attach directly, some wont.

RRR · 09/13/2012, 11:32 PM

Awesome, can't wait to try it out on my TG-16

Freezer · 09/13/2012, 11:35 PM

Great diagram. Makes me wish I hadn't already A/V modded my TG16. If I hadn't I would have totally done this S-Video mod. Oh well, maybe in the future I'll add it.

HercTNT · 09/13/2012, 11:38 PM

The two of you need to keep up the good work. idiots like me need these diagrams to keep from blowing things up.

Drakon · 09/14/2012, 06:50 AM

Quote from: HercTNT on 09/13/2012, 11:38 PMThe two of you need to keep up the good work. idiots like me need these diagrams to keep from blowing things up.

I get worried when someone who can't read diagrams tries to mod it themselves. I always prefer the idea of hiring an experienced modder. I get clients frying a lot of expensive hardware because they wanted to try stuff themselves. Even when I started modding I sat down and learned how to read simple shematics before doing the actual mods.

Quote from: PCEngineHell on 09/13/2012, 06:37 PM
Quote from: Drakon on 09/13/2012, 06:19 PMNo need to solder straight to the ic pin. I soldered to the surface mount resistor that the trace connects to you'll get a much bigger spot to solder with doing that.
Yeah I noticed too that between the Tg16 on that pin and on Pce Duo-R that the TG had a bit more/wider soldering area then the other system on pin 40 to attach to on that pin if you decide to solder there, so the pin spot on the TG-16 is easy to use. But in general, as long as you solder on something leading to that pin then it works. If I remember right too the Duo-R has a tiny solder blob leading off of a trace to pin 40 that is very close by, so you can solder on to that too if need be. If you don't have steady hands I'd def recommend finding a spot leading to the pin to attach to, or use a very fine point soldering iron.

Basically why I didn't bother posting any pic of any wires actually soldered to the pin directly, as the layout seems to vary some between systems. Everyone is just going to have to choose the spot leading to the pin that works best for them. Some people will want to attach directly, some wont.

Yeah I understand why you did it this way. When I first posted my improved 32x s-video mod one guy was so non steady he took off the solder pad when removing the 0 ohm resistor and wasn't able to solder to the ic pin. If he hadn't removed the solder pad he could have used that which would have been much easier, but it's certainly not impossible to solder to the pin on the ic, it's just more annoying. Also if the duo doesn't have the expansion port maybe you should show which pin is 5v on something easy to show in a picture like the power regulator?

PCEngineHell · 09/14/2012, 07:50 AM

Quote from: Drakon on 09/14/2012, 06:50 AMI get worried when someone who can't read diagrams tries to mod it themselves. I always prefer the idea of hiring an experienced modder. I get clients frying a lot of expensive hardware because they wanted to try stuff themselves. Even when I started modding I sat down and learned how to read simple shematics before doing the actual mods.

To be honest, everyone has to start somewhere, and to suggest someone not try and opt to hire someone instead is just discouraging, making it out like this is something only for the elite, and its most certainly not. Some people learn better by getting their hands dirty getting right to the work, and there are plenty of folks out there with more then capable soldering ability from doing cap repairs, etc, who simply never learned to read a schematic. There is no reason why something like having to decipher squiggly line symbols and arrows should somehow hold someone back if they otherwise have steady hands and could do the work once they are told what parts they need and where to solder. A complicated schematic is only doing one thing for the person having trouble reading or having never read a schematic, being complicated. There are better ways to share knowledge then that if you want to reach a broader audience.

Quote from: Drakon on 09/14/2012, 06:50 AMAlso if the duo doesn't have the expansion port maybe you should show which pin is 5v on something easy to show in a picture like the power regulator?

I am not sure what you mean here. My understanding is the Duo has the same AV port as the Duo-R with the exact same pin out. That means that per what the schematic states, 5 volts can be pulled from Pin 4 of the AV port. If it helps you understand which pin to tap it from, I have revised to include a view of the bottom of the port showing its solder points, which have been labeled for easy understanding for anyone who cant figure out which solder point goes to what pin.

Drakon · 09/14/2012, 03:23 PM

What I mean is if the person isn't willing to learn how to read a simple schematic. Then they're most likely not patient enough for modding. A schematic involving 1 transistor a couple of resistors and 1 cap isn't complicated at all to learn. My schematics are already highly simplified showing pictures of the actual parts. I admire you making a super easy to follow guide. I've seen lots of threads on forums where people try to follow some super dumbed down guide but still manage to mess it up all over the place. I don't try to make mods for "elites" only I just like to keep it difficult enough that if you demonstrate enough patience to learn how to read and wire it then you should have enough patience to get it done right.

I've never had a duo in my posession I didn't know if it has the same expansion port as the tg16 / pc engine. I'm pretty certain that all consoles contain a 7805 voltage regulator. If they all use the same expansion port then using the expansion port's fine.

thesteve · 09/14/2012, 04:19 PM

drakon the duo does not have the expansion port, but has 5V at the AV port.
ALL DUO's have the same AV port, as do some PCE's

Drakon · 09/14/2012, 06:42 PM

Quote from: thesteve on 09/14/2012, 04:19 PMdrakon the duo does not have the expansion port, but has 5V at the AV port.
ALL DUO's have the same AV port, as do some PCE's

Oh okay so maybe grabbing from the regulator is more of a universal spot.

HercTNT · 09/14/2012, 06:44 PM

Quote from: Drakon on 09/14/2012, 03:23 PMWhat I mean is if the person isn't willing to learn how to read a simple schematic. Then they're most likely not patient enough for modding. A schematic involving 1 transistor a couple of resistors and 1 cap isn't complicated at all to learn. My schematics are already highly simplified showing pictures of the actual parts. I admire you making a super easy to follow guide. I've seen lots of threads on forums where people try to follow some super dumbed down guide but still manage to mess it up all over the place. I don't try to make mods for "elites" only I just like to keep it difficult enough that if you demonstrate enough patience to learn how to read and wire it then you should have enough patience to get it done right.

I've never had a duo in my posession I didn't know if it has the same expansion port as the tg16 / pc engine. I'm pretty certain that all consoles contain a 7805 voltage regulator. If they all use the same expansion port then using the expansion port's fine.

I can't read schematics and i mod all the time. Also, modding is for everyone, some people learn by example and not by reading charts. Its done right when it works.

thesteve · 09/14/2012, 07:29 PM

http://www.learn-c.com/schemat.htm

HercTNT · 09/14/2012, 07:34 PM

well thats fine and dandy, but without someone to tell me what it all means it does not help me much.

turboswimbz · 09/14/2012, 07:51 PM

now see I have the opposite problem, I can read the schematics all day long. (thank you 70 hours of science credit hours) Hell I've even made things on practice bread boards, but when I try to do my own stuff, with real electronics and soldering, I never seem to be able to make the repair correctly. Although reading the modding boards here has me thinking about trying again, Maybe the next turbo-16 I come across will be fiddled with.

HercTNT · 09/14/2012, 07:55 PM

everyone is different, some people have the manual skill but the lack of book smarts, some have the book smarts but lack of manual skill. usually though most go to school to learn how to do this stuff and can't simply absorb it. What freezer and the professor are doing is making simplistic easy to follow walk throughs that help those of us who are not as gifted.

turboswimbz · 09/14/2012, 08:03 PM

Quote from: HercTNT on 09/14/2012, 07:55 PMeveryone is different, some people have the manual skill but the lack of book smarts, some have the book smarts but lack of manual skill. usually though most go to school to learn how to do this stuff and can't simply absorb it. What freezer and the professor are doing is making simplistic easy to follow walk throughs that help those of us who are not as gifted.

Yeah, and I think it's great. Just saying that for me, it's not the schematics that hang me up, so to say that everyone should learn them is silly, because learning them did me no good. However, I've met many who can simply pick it up and with a minimal amount of guidance, and do a 100% better job than me.

HercTNT · 09/14/2012, 08:06 PM

My comment was more of a general one, thats why i did not quote you. I actually agree with you and thought you made a good point

turboswimbz · 09/14/2012, 08:08 PM

ha. oops, read yours wrong, lol. it makes sense now.

HercTNT · 09/14/2012, 08:10 PM

no worries

Drakon · 09/15/2012, 06:59 AM

Quote from: HercTNT on 09/14/2012, 07:34 PMwell thats fine and dandy, but without someone to tell me what it all means it does not help me much.

I used google to learn. I really doesn't take that much effort. People not being able to do it right is what worries me. Like I said some of my clients send me messages about how many systems and expensive hardware they fried trying to do things on their own. Heck some clients got fried or improperly built hardware because they cheaped out and got some amateur modder to try to get the work done. I think this super easy guide is a good thing, I'm just concerned about people bridging the pins on the IC and killing their systems. They're more than welcome to try. I've been around a lot of modding forums where people follow ultra beginner friendly guides and I get to see how much hardware gets murdered.

HercTNT · 09/15/2012, 11:02 AM

I understand why you would be concerned about those that try to sell shoddy work. Just saying there are alot of us that mod for our own private use and our inability to read a schematic does not diminish our patience or the quality of our work. I know that was not the intent of your comment

PCEngineHell · 09/15/2012, 02:57 PM

Lets stay on topic here please, which is just about the svideo mod itself. If you want Drakon, you could write up a guide with tips and pics to help people new to soldering make the transition easier, and post it it in another thread, maybe help a few avoid making certain mistakes.

Drakon · 09/15/2012, 07:12 PM

I don't feel the need you can just google it. Now that you have pictures of where to get 5v from every model it's pretty much as good as it can get.

Quote from: PCEngineHell on 09/15/2012, 02:57 PMLets stay on topic here please, which is just about the svideo mod itself. If you want Drakon, you could write up a guide with tips and pics to help people new to soldering make the transition easier, and post it it in another thread, maybe help a few avoid making certain mistakes.

PCEngineHell · 09/15/2012, 07:44 PM

Quote from: Drakon on 09/15/2012, 07:12 PMNow that you have pictures of where to get 5v from every model it's pretty much as good as it can get.

I agree. I dont have any issues reading schematics myself, but I found that people ended up liking that one Sony CX one I did due to its ease of use, so hopefully people will find this one helpful. Other then the schematic, all people really need is a good soldering iron, good wire, maybe a good desoldering pump just in case they make a mistake, dremel or power drill, and the parts needed for the mod.

Quote from: Drakon on 09/15/2012, 07:12 PMI don't feel the need you can just google it.

There is actually a nice amount of soldering and desoldering tips videos up on youtube if someone needs them in case they are a beginner at soldering.

tpivette · 11/02/2012, 10:35 AM

Bumping this, as it was a few pages back and I'm going to use it as a reference when modding my spare TG16 soon. Thanks for the diagram!

Keith Courage · 11/02/2012, 01:41 PM

Thought I'd post an update on doing S-video for a TG16 or PC engine that originally had the RF out. This is the easiest S-video mod to do. Some of you may already know this but I found better spots to tap moist signals needed. You can tap 5V and the Composite sync straight from two of the pins that originally went to the RF out. So if you de-solder your RF you can do your mod this way. So this saves having to run really long wires all the way to your expansion port and makes a sturdier connection for the transistor. Also, make sure to still use a 0.001 capacitor. There isn't one in the picture shown. I temporarily hooked it up that way for quick testing purposes.

/cimg6863.jpg
/cimg6867i.jpg

fsa · 11/02/2012, 04:01 PM

Thanks for the pic Keith Courage and the diagram ProfessorProfessor (Props to you guys), now I am able to add Svideo to my turbo which is long overdue. I was going to do the AV mode but will also incorporate the SVideo at the same time. Man I got to say its great having guys like you willing to share their knowledge with others. Thanks and I hope my mod works.

vxbinaca · 11/02/2012, 07:52 PM

Nice!

Nec.Game.head · 12/02/2012, 04:25 PM

I had a question regarding the picture with all the pin outs ?? At the bottom left corner that says BOTTOM OF AV PORT ON DUO SYSTEMS, does that also apply for my Duo-R ?? I looking to AV mod it myself, so that later in the future when I decide to have it RGB modded I can have my audio come out from those output jacks ...

PCEngineHell · 12/02/2012, 04:42 PM

AV Port is the same for all Duo models.

DildoKKKobold · 12/29/2012, 10:03 PM

Quote from: Keith Courage on 11/02/2012, 01:41 PMThought I'd post an update on doing S-video for a TG16 or PC engine that originally had the RF out. This is the easiest S-video mod to do. Some of you may already know this but I found better spots to tap moist signals needed. You can tap 5V and the Composite sync straight from two of the pins that originally went to the RF out. So if you de-solder your RF you can do your mod this way. So this saves having to run really long wires all the way to your expansion port and makes a sturdier connection for the transistor. Also, make sure to still use a 0.001 capacitor. There isn't one in the picture shown. I temporarily hooked it up that way for quick testing purposes.

Thanks for this. Just finished up fixing a TG16 I got with a broken RF port, so this mod was perfect for that. This has now become my main TG16 for streaming video. The picture quality is mind-blowingly good. Thanks again, couldn't have done it so nicely without this image.

blueraven · 12/29/2012, 10:08 PM

I dig this, simple and effective. This is kickass, Prof.

HercTNT · 12/29/2012, 11:14 PM

want to do this myself, thanks mike for the circuit, thanks keith for the pic.

Duo_R · 12/30/2012, 12:25 AM

Nice to see you guys placing the svideo port in place of the rf port. Here is an idea for the audio - place a mini jack plug where the channel selector used to be.

/imagetpe.jpg

HercTNT · 12/30/2012, 06:02 AM

duo, would love to see the internal on that one.

Duo_R · 12/30/2012, 04:09 PM

I should have taken pictures but was in a rush. Its pretty straightforward, gutted the RF box, then dremelled holes for the Composite video and audio jack. Then connected to the expansion port internally.

jamisonia · 01/14/2013, 03:22 PM

You guys are wiring the composite video straight into the Chroma pin? That can't be right. Wouldn't the damage already be done to that Chroma, since its mixed with Luma before you're tapping it? Does that chip produce Chroma by itself?

ApolloBoy · 01/14/2013, 06:17 PM

Quote from: jamisonia on 01/14/2013, 03:22 PMYou guys are wiring the composite video straight into the Chroma pin?

It goes through a capacitor first so no, it's not straight into the S-video jack. I take it you've never seen S-video on the PCE/TG-16 in action?

jamisonia · 01/14/2013, 06:40 PM

Quote from: ApolloBoy on 01/14/2013, 06:17 PM
Quote from: jamisonia on 01/14/2013, 03:22 PMYou guys are wiring the composite video straight into the Chroma pin?
It goes through a capacitor first so no, it's not straight into the S-video jack. I take it you've never seen S-video on the PCE/TG-16 in action?

I have not yet. I see it goes through a very small capacitor. My concern would be since the chroma is already part of composite signal, and has been mixed with Luma, hasn't the damage already been done?

NightWolve · 01/14/2013, 06:42 PM

Quote from: jamisonia on 01/14/2013, 03:22 PMYou guys are wiring the composite video straight into the Chroma pin? That can't be right. Wouldn't the damage already be done to that Chroma, since its mixed with Luma before you're tapping it? Does that chip produce Chroma by itself?

Yeah, what Apollo said, the cap acts as a decent filter, but if you want the *best* result you can disconnect the Luma in the amplifier circuit so that at the end of the Composite output all you would have is Chroma, and thus no need for a filtering cap. That's how I wanna do my S-Video mod eventually and make a diagram for it as well.

You asked previously how this S-Video craze got started. Best as I can trace it back to would be first here:

https://www.pcengine-fx.com/forums/index.php?topic=9150.0

Bonkuts/TurboXray posted the circuit for the NEC Composite amplifier which showed that a working Luma was being outputted by the 6260 video chip and then thesteve posted his initial design for an amp here:

https://www.pcengine-fx.com/forums/index.php?msg=206287

So I'd say early 2012 is when things kicked off with Steve's initial circuit there. Then Keith Courage made the first clear, big image here revising it a bit after consulting with thesteve.

Drakon actually did it another way in the link below which was something I had been consulting thesteve about. I wanted to know if there was a superior way to produce/obtain a clean Chroma and if that was better than a filtering capacitor. He said yeah, it is. So here's that, (disconnecting Luma from the Composite amp to get a clean Chroma):

https://www.pcengine-fx.com/forums/index.php?topic=12339.0

(I wouldn't recommend his technique for disconnecting Luma though. I wanna find an early trace and just razor it to achieve disconnection, rather than his idea of soldering off a resistor... This way, you could scrape both ends of the trace and solder them back to restore it if you wanted or connect to a manual switch. Anyhow, you get the idea of what is trying to be accomplished here from that image.)

I wanna put all that together eventually but with a Luma + Chroma mix, since while this idea gives you the best possible S-Video, it breaks Composite output. So to do this right, you'd break the trace of the Composite output near the AV-Out and you'd add a basic Luma+Chroma Mix to restore back Composite support. So, you'd get the best possible S-Video output, while still having Composite support, only that it would be slightly inferior...

I think that is the circuit that those bi-directional S-Video-to-Composite adapters use. That's what you'd need to do if you did this the more involved way. It will be slightly inferior, yeah, but the benefit of the best S-Video output outweighs that con I feel. In principle, you'll stop using the Composite output anyway after such a mod. Thing is though, a lot of new TVs are phasing out S-Video support and you'll only find Composite, Component, or HDMI, etc. So, you don't want to be lazy and permanently break Composite support to get this quality gain, so it'd be smart to restore it this way should you go this extra route. There is a possibility that connecting that 470pF cap to your perfect Chroma and Luma lines to restore Composite ruins them when they travel out the S-Video jack... That was the other thing I was thinking of, so you'd want to put two new transistors so as not to attenuate your S-Video output in order to restore Composite and not have it interfere... (I dunno for sure if this will happen, haven't done it yet, but it's a concern). Not a problem at all if you don't care about restoring Composite though. You would simply have to make sure you get one of these:

So that if you switch to a TV without S-Video, you could still use Composite with it. Or, look into the Component mod we've been working on, once again, thanks to thesteve. I think Professor mentioned that these adapters can be better than the native Composite output if you've got S-Video to work with. I bought a cable that does this from RadioShack for a $1 (RS, can you believe it??), a close out item, but my experience is that it's probably that cheap circuit I linked above because the quality is inferior than the existing Composite output that I tested it against from my BluRay player. Anyhow, if you want the best, there ya go! ;)

thesteve · 01/14/2013, 07:17 PM

that bI-directional mixer, is just that.
it would (contaminate your Luma, with chroma.

NightWolve · 01/14/2013, 07:27 PM

Ah, thanks for confirming it! So would my idea for a way out work ? Basically, having gone this extra route, you've got a clean Chroma line going to the S-Video jack and a properly prepared Luma line as well. You tap this clean Chroma and Luma, add transistors, attenuate them down properly with resistance and then connect that combining capacitor on the output end, thus restoring a Composite signal AFTER 2 extra transistors...

Would that prevent the contamination ? You combine them AFTER 2 transistors? If not, fuck it, just sacrifice the Composite output for good and purchase one of these adapters or cables and keep it handy should you have to switch to a TV that only has Composite some time in the future.

thesteve · 01/14/2013, 08:34 PM

yes on the transistors, dont attenuate.
better idea is simply isolate the signals from the chip, mixing the luma/chroma after the first transistor
then have a transistor pair for S-Vid and the stock (almost) amp

NightWolve · 01/14/2013, 08:59 PM

Your circuit from the 3.5" LCD mod thread:

1) Break the Luma trace in the internal amp so at the Composite output, you have a clean Chroma.
2) Tap the Luma pin, build the well-known amp at the start of this thread, connect both clean Chroma and Luma to female S-Video jack.
3) Build your circuit pictured above (extra soldering to pins in question) to maintain Composite support, and who cares if it's slightly inferior since you'll mostly be using S-Video after this mod.
4) Break the Composite trace at some point near the AV out and connect it to this simpler amp, achieving a bypass, etc.

All in all, I would need 5 resistors and one transistor for this extra distance idea. (Of course, this was for TE and no lifting and grounding pins is necessary.)

Thumbs up or ? I think you cited a simpler idea but I can't visualize it from what I read.

thesteve · 01/14/2013, 10:13 PM

simpler yes
do the amp from luma (like S-Vid scat)
connect a resistor from it to after the first transistor in the composite circuit.
connect amp shown above twice (once without luma, and again with just luma)

jamisonia · 01/15/2013, 12:40 AM

Quote from: thesteve on 01/14/2013, 07:17 PMthat bI-directional mixer, is just that.
it would (contaminate your Luma, with chroma.

This is cheesy but this reminded me of that you got peanut better in my chocolate, no you got chocolate in my peanut butter commercial.

You got Chroma in my Luma... no you got luma in my chroma!

NightWolve I agree that simply cutting the trace would be more desirable than removing the resistor. Its just strange that the PC Engine doesn't create fully formed Chroma before Luma is mixed in. Its not ideal to remove features.

TVs have already dropped s-video. My Plasma was mid range in 2012, and did not have either VGA input or s-video. However I keep around a Sony Wega for retro gaming. Of course if that YPbPr mod comes out and looks good I'll just skip s-video and go straight to it.

thesteve · 01/15/2013, 01:23 AM

it works and looks decent
just need wolve to verify my schematic, so we can have boards made

Keith Courage · 01/15/2013, 01:30 PM

I prefer S-video myself since I still like to do all of my gaming on a CRT TV. I hate playing games on a flat screen. I can't stand seeing the picture all streched out or a square in the center with black all around it. So for those of us who prefer CRT gaming S-video is still a great option.

jamisonia · 01/15/2013, 03:50 PM

How abuot a CRT with YPbPr inputs? Many of the later SD CRTs had them. Might I suggest trying to track down a KV-xxFV310. the xx is the size, which ranges I beleive from 27 to 36". This TV has a subwoofer inside the TV, better speakers than most TVs. It also has a 3D Comb Filter which is the best comb filter designed, great for composite only systems (Only the NES remains I believe), and finally the coup de grace for me was 2 YPbPr Inputs, 2 S-video Inputs, and 1 additional Composite only input. Additionally you can maintain a separate calibrations on the YPbPr and other inputs, and it has a Pro Calibration mode. Its really the best SD CRT one can find.

10/31/2023: Localization News - Dead of the Brain 1!

S-Video Mod Schematic for the Schematic-Illiterate (For TG-16/Duo etc)