PC Engine / Turbografx16 s-video mod

[PCEngineHell]

Thanks for this mod Drakon, and others who helped too of course! I just did this mod on my US TG16, worked flawlessly. The picture is AWESOME, it even fixes that horrible shimmering that is always there on composite when scrolling. Hyperdyne Sidearms looked like shit now it looks as sharp as on an emulator!

I figured the solder points with the schematic. I still need to hook up audio and fine tune the resistor value for optimal brightness.

Once im done ill make a diagram with a picture of the US motherboard, maybe it will help people wanting to mod their US TG16.

Svideo mod has already been covered here by a few members including myself. I posted one that showed what pins exactly to tap on the US TG-16 expansion port for composite and 5 volt, so another would not be needed in regards to that. https://www.pcengine-fx.com/forums/index.php?topic=13044.0

[EvilmaxWar]

The picture is AWESOME, it even fixes that horrible shimmering that is always there on composite when scrolling. Hyperdyne Sidearms looked like shit now it looks as sharp as on an emulator!

Hm, that's kind of a good way to describe it, a "shimmering" effect when scrolling. I was actually trying to find a better way myself besides referring to it as dot crawl, which I think is mostly what's responsible for that (100% when it's a composite signal), but even with a S-video test on my Turbo Duo and my SNES, while it was greatly reduced, there was still some of this shimmering left. In the case of my SNES, after the component video mod was put into place, THEN it was beautiful, frankly, and that effect was practically eliminated! Clear coloring, no interference artifacts, good sharpness, contrast, scrolling, etc.

Im not sure this effect is all that much related to composite dot crawl. Even though dot crawl would seem to be a good name for it. True dot crawl will appear on a still image as well (Playstation splash screen).
This is different, it only happens by a noticeable amount on the NES, PCE and i think SMS has it too. It only happens on moving objects or scrolling and the severity depends of the scrolling speed. Im not sure exactly what causes it.

I even created a thread about it on assembler games and its pretty funny as everyone had a different explanation for it.
http://www.assemblergames.com/forums/showthread.php?42005-NES-caracteristic-Dot-crawl-while-scrolling-shimmering-shifting-pixels

[Drakon]

Yeah, I made this thread because the title makes it obvious this's where the information can be found.  Then you made another thread about the same thing, which could have just been posted in here.  I wasn't trying to claim I invented the mod, I just wanted to make a thread with a very clear title that this's where information on the s-video mod can be found.

Thanks for this mod Drakon, and others who helped too of course! I just did this mod on my US TG16, worked flawlessly. The picture is AWESOME, it even fixes that horrible shimmering that is always there on composite when scrolling. Hyperdyne Sidearms looked like shit now it looks as sharp as on an emulator!

I figured the solder points with the schematic. I still need to hook up audio and fine tune the resistor value for optimal brightness.

Once im done ill make a diagram with a picture of the US motherboard, maybe it will help people wanting to mod their US TG16.

Svideo mod has already been covered here by a few members including myself. I posted one that showed what pins exactly to tap on the US TG-16 expansion port for composite and 5 volt, so another would not be needed in regards to that. https://www.pcengine-fx.com/forums/index.php?topic=13044.0

[PCEngineHell]

Yeah, I made this thread because the title makes it obvious this's where the information can be found.  Then you made another thread about the same thing, which could have just been posted in here.  I wasn't trying to claim I invented the mod, I just wanted to make a thread with a very clear title that this's where information on the s-video mod can be found.

Thanks for this mod Drakon, and others who helped too of course! I just did this mod on my US TG16, worked flawlessly. The picture is AWESOME, it even fixes that horrible shimmering that is always there on composite when scrolling. Hyperdyne Sidearms looked like shit now it looks as sharp as on an emulator!

I figured the solder points with the schematic. I still need to hook up audio and fine tune the resistor value for optimal brightness.

Once im done ill make a diagram with a picture of the US motherboard, maybe it will help people wanting to mod their US TG16.

Svideo mod has already been covered here by a few members including myself. I posted one that showed what pins exactly to tap on the US TG-16 expansion port for composite and 5 volt, so another would not be needed in regards to that. https://www.pcengine-fx.com/forums/index.php?topic=13044.0

Your mod only covered the PC-Engine, not the TG-16 or Duo, etc, which mine did, and though I haven't looked back on it in awhile, because at the time it was kind of sloppy, it seemed like you removed components from the game system that did not need to be removed, to compensate for being afraid of soldering directly to a pin on the 6260. I have not bothered to look and see if you corrected that or not. Maybe if I get a white PC-E or Coregrafx sometime I will get around to doing it in detail myself if you have not done so by then, after I take a good solid look inside one, and add it to the thread I did to make it easier for some to read. I'd rather have a thread for my own schematics at any rate, instead of posting them in someone else's page way down the road, as they will get lost in the shuffle more easily.

[EvilmaxWar]

I haven't looked back on it in awhile, because at the time it was kind of sloppy, it seemed like you removed components from the game system that did not need to be removed, to compensate for being afraid of soldering directly to a pin on the 6260. I have not bothered to look and see if you corrected that or not.

I Do not know if you are referring the the resistor, but i thought the point of removing it was to get a stronger Luma signal but also to prevent the luminance from being mixed with chrominance down the line, possibly resulting in a better image. Please correct me if i am wrong here.

I also do not like to solder directly on IC legs, especially when I do not have to do it. On my TG16 I certainly did not need to do that. Ill post picture of the solder points i used when i get back from job tonight.

[Drakon]

What?  I didn't remove anything out of fear, I removed the resistor so luma and chroma wouldn't get mixed together producing a sharper image.  What you're saying makes zero sense, you don't need to remove a surface mount resistor to solder a wire to one side of it.  And you could have posted your stuff in this thread, I would be happy to update the first post with new information.

Evilmaxwar is correct, I'm all about getting the best quality image possible.

[Keith Courage]

Yeah, and I posted a chart here as well. So basically the good news is that a lot of us here in the forums know how to do this now. Haha https://www.pcengine-fx.com/forums/index.php?topic=10850.105

[PCEngineHell]

What?  I didn't remove anything out of fear, I removed the resistor so luma and chroma wouldn't get mixed together producing a sharper image.  What you're saying makes zero sense, you don't need to remove a surface mount resistor to solder a wire to one side of it. 

To that I will just point back to your prior post, as that is what gave the indication that you may have some fear of soldering directly to the pins.

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.

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?

And you could have posted your stuff in this thread, I would be happy to update the first post with new information.

Or not. I don't rely on others to post my own tech info. Why would I? And by this thought process, why didn't you just post this said info on the other thread done prior to yours? If it differs in some way then what is already present, and is original enough in some way to warrant it being posted, I am going to post it in my own thread, not piggyback my own work in vivid detail on someone else's, which I would consider to be slightly disrespectful. I would hope others do the same, unless people are all collaborating on one certain project together at once. Someone (Keranu, or Joe) could always make a thread that is stickied that refers to all of these threads, containing links to the actual mod content if they like, to make them easier to find. Otherwise, ALL of them eventually over time will float downriver and be harder to find without using the search engine.

[EvilmaxWar]

Here are some pictures of how i did the mod on my US TG16. I did not bother remaking a full diagram, I just indicated the solder points and the resistor to remove on the board.
If someone wants to use or modify these pictures, i dont mind.  ( If you want to see larger version open picture in separate window and remove the "h" at the end of the file name. )

First i cut the lead from the resistor R130, to remove Luma from the mixing circuit.


On the following picture you notice i made all the soldering on the underside.
I did not use the connector pins to grab my 5v or CVBS, instead I used points in the video mixing circuit. This allowed me to have all the wires in the same spot, hopefully making a more tidy mod.    I had also wired audio but ended up removing it and opted to keep using my TurboBooster instead. The signal from those pins is quite weak. I also felt that maybe it sounded a bit dry compared to the TurboBooster, even after I had raised the volume on my sound system to compensate.  The TB boosts the volume but i think it also adds some warmth to the sound.   

Also, I used a 2N4132 Transistor instead of the 2N3904, for the simple reason that i already had those. They seem to be similar enough for it not to matter. I used a trimpot to adjust the brightness and settled at 225 ohms.

[Drakon]

What?  I didn't remove anything out of fear, I removed the resistor so luma and chroma wouldn't get mixed together producing a sharper image.  What you're saying makes zero sense, you don't need to remove a surface mount resistor to solder a wire to one side of it.

To that I will just point back to your prior post, as that is what gave the indication that you may have some fear of soldering directly to the pins.

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.

I soldered to the surface mount resistor, I didn't say you have to desolder it, you can just solder to the one side of it which's still a lot bigger than the IC pin.  It's not a fear thing I'm just trying to make it easier for people.  The whole point of posting everyones guide in one easy to find thread is that people don't have to go looking everywhere for all info.  I'm not trying to be against everything you do I'm trying to work as a team.

Thanks for the great pictures eveilmaxwar!

[chipperkwah]

Wanting to get dirty with some s-video on my Duo R, wondering if anyone has done the mod on their duo and taken photos of it? I assume that the R130 resistor should be easy to find, but I haven't opened it up yet to check. Too busy with blood gear. Also, if I remove the stock din and replace it with an s-video din I'm not sure how I would go about getting audio. I could always replace it with a din that has plenty of pins and make a cable that terminates in s-vid and stereo rca, but that's a pain. Anyone have a better idea? Would rather not drill holes to make room for new audio jacks.

[PCEngineHell]

Wanting to get dirty with some s-video on my Duo R, wondering if anyone has done the mod on their duo and taken photos of it? I assume that the R130 resistor should be easy to find, but I haven't opened it up yet to check. Too busy with blood gear. Also, if I remove the stock din and replace it with an s-video din I'm not sure how I would go about getting audio. I could always replace it with a din that has plenty of pins and make a cable that terminates in s-vid and stereo rca, but that's a pain. Anyone have a better idea? Would rather not drill holes to make room for new audio jacks.

Alternatively you could hit up this thread:

https://www.pcengine-fx.com/forums/index.php?topic=13044.0

Drakons fled the scene so to speak, rather wishing to focus on trashing peoples efforts on his own forums and taking credit for others work elsewhere I was last told, so I don't think he would be able to help you out on his mod here. This is basically one of those threads better left to die. If you do want to discuss Drakons method and how to improve it, you can google his name and you should come up with some results showing what forums he is currently on or something so you can contact him directly. If you're really lucky too, he may offer to do the work for you for about 400 bucks or so. He may, or may not, include even drilled holes with the modwork. That might cost extra.

[chipperkwah]

Ah I see. I had previously read through your thread as well and it seems that both circuits are almost identical, except that yours uses a cap as a filter while this mod opts to remove the resistor in order to get a clean chroma signal. I feel like both methods should yield very similar results, someone correct me if I'm wrong. I must say though that the schematic photo you made is much nicer looking. I would have to pass on his $400 mod fee , as I'm perfectly capable of doing this myself. Sorry to revive an old topic, seems as though there was some bad blood associated with this in the past.

[thesteve]

alternately the cap is optional, as most displays should just ignore the luma on the chroma pin.
several DUO mods have been done, adding the connector to the back of the unit

[chipperkwah]

alternately the cap is optional, as most displays should just ignore the luma on the chroma pin.
several DUO mods have been done, adding the connector to the back of the unit

I know you're the resident video guru, so in your opinion would it be best to pull the resistor/cut the trace or use a cap on the chroma line? Just curious, since it seems like both ways work. I wasn't aware that most screens would ignore the luma anyways, good to know.

edit: I have no interest in using composite video again once I do the mod, so I'm not bothered if getting rid of the resistor gets rid of composite.

[NightWolve]

I know you're the resident video guru, so in your opinion would it be best to pull the resistor/cut the trace or use a cap on the chroma line? Just curious, since it seems like both ways work. I wasn't aware that most screens would ignore the luma anyways, good to know.

edit: I have no interest in using composite video again once I do the mod, so I'm not bothered if getting rid of the resistor gets rid of composite.

There's a simple pro/con to it. A clean Chroma signal that isn't contaminated with Luma at all will be better than using a filter cap from a Composite signal where both have been mixed in. So yeah, if you disconnect the Luma (break resistor/trace) from the Composite amplifier, all you'll be getting out of the Composite output is a clean and properly amplified Chroma signal which will be perfect for S-Video use. The con here is that you're breaking default Composite support, so you can either build another circuit/mixer to maintain it or not care. Since you're indicating that you don't care, then I'd say do it this way. You'll get the best S-Video signal, but will break Composite support. If that trade-off is acceptable to you, then this is the best way.

[chipperkwah]

Right on, thanks for the info guys. Very excited for some crisp s-video. Not that the duo composite is particularly horrible, but might as well have it looking as good as possible.

[NightWolve]

You know, I thought of something. You don't have to really break Composite support over this and there's a much better way than building another circuit. Back when I was inspecting new LCD TVs to see how many had S-Video (very few nowadays), I noticed a trick they did to save space in supporting both Composite and YPbPr Component signals:  Instead of 4 RCA jacks (yellow, green, blue, and red), they reduced it to 3, but the green jack for Luma was colored half green/half yellow to indicate that it accepted a Composite signal and thus would digitally switch to it if detected.

Based on that idea, when I did my SNES Component mod, I drilled the holes for a triple RCA jack mount (green, blue, red) but I also bought a little switch and later added that, so when the switch is on the Luma side, Component works, but when I flip the switch, the same green jack outputs a regular Composite signal. This way, I didn't have to drill a big 4th hole for a yellow RCA jack for Composite.

Anyhow, based on this idea, all you need is a simple switch. You'd find that resistor (or trace) that delivers Luma into the Composite mixer/amplifier, you'd solder off one end, then solder wires from and to, and those wires would go to the manual switch (placement would have to be determined, next to the S-Video jack perhaps), etc. OK, so idea is, when you're using S-Video, the switch is in the off position, disconnecting Luma from the Composite mixer, but say you get a new TV which doesn't have S-Video support, boom, just flip the switch and now default Composite support is restored.

I was asking steve something more complicated and needless (which I see now) in the other thread, which was what's the best way to build another circuit to maintain Composite support. But, that idea is totally replaceable by the switch idea and there's no possibility of contamination... If you don't mind buying the right switch and drilling another hole for it, it'll do the trick just fine!

[EvilEvoIX]

I need to get my TG16 modded.

[chipperkwah]

Anyhow, based on this idea, all you need is a simple switch. You'd find that resistor (or trace) that delivers Luma into the Composite mixer/amplifier, you'd solder off one end, then solder wires from and to, and those wires would go to the manual switch (placement would have to be determined, next to the S-Video jack perhaps), etc. OK, so idea is, when you're using S-Video, the switch is in the off position, disconnecting Luma from the Composite mixer, but say you get a new TV which doesn't have S-Video support, boom, just flip the switch and now default Composite support is restored.

That's an excellent idea, it would be ideal if I could have both. Looks like I'll be drilling an extra hole.

[fsa]

I need to figure out where to mount a S-video connector on a CG unit, I suppose I could replace the 5 din connector with an 8 din and make two pins s-video (with a custom s-video cable). With the CD-unit that I have there really aren't that many options on locations to install. I assume s-video works fine in conjunction with CD-rom unit.

I have been toying with the idea of using a female 3.5mm stereo plug and build a custom Svideo cable with a male 3.5mm on one end because the female jack is much smaller and easier to install ( the ones with the with the small ring screw).