Where can I tap a sync signal for s-video?

[Keith Courage]

Well, after all the work messing around with the ground in my DUO and cables on my TV it turns out that the problem is my TV. I just remembered that I used to have issues with vertical lines when I used a DVD player on it before with S-Video. To test this out I grabbed my old 27 inch Toshiba out of my closet and hooked it up. Dam does the S-Video look good and no lines whatsoever. I think I might end up trying to find myself a different CRT TV cause my 36" Sony Trinitron just doesn't do S-Video without showing verical lines. Thanks for the help though. This is a killer mod with the right TV.

[ApolloBoy]

I'm in the process of trying this mod on a white PCE I got from Samurai Ghost, I'll let you guys know how it goes!

[Keith Courage]

I was actually surprised how easy it is once I got used to it. I was making it way more difficult in my head until you guys helped me out.  Really the difficult part is just trying to figure where or how to mount the S-video jack itself. On a pc engine you would be best using the kind you can solder to the board since you can remove the RF and have a nice big space of ground to mount to. With my DUO-R I went with a plastic style jack that screws into the casing as opposed to one that you solder to the board. I added some glue to the jack to make sure mine was solid cause one screw is hardly enough to hold the pressure of pushing the cable in.

[thesteve]

ive done 1 with the jack having a metal box (like the controller port) and i soldered it to the RF shield (the one pictured above)
the next had no shell, so i braced it and glued it to the housing

[ApolloBoy]

That's exactly the technique I used, I just removed the RF modulator and in its place soldered on a PCB mount S-video jack. I also put in some audio jacks, one on each side of the expansion port. I also used a 220 ohm resistor since I originally wanted to try a 200 ohm like Keith but only had 220s laying around. The colors are a tad bit washed out, but I think that might be because I'm more used to RGB these days.

But overall I'm pretty pleased with the result and now I have a PCE I can tote around to meetups and stuff with my friends!

[thesteve]

this is a close-up of my ship in image fight showing S-Video VS Composite (2 pics)
note how the color bleeds between objects on Composite:

S-Video:


Composite:

[Keith Courage]

I just made a diagram to help those of you out who want to upgrade your video to S-video. Especially since I was confused myself when I first did this without seeing any pics. There is also info on where to tap the needed signals for both a DUO system or a standard TG16/pc engine.


https://postimg.cc/qN0JrWD8

[city41]

That diagram is great. I think I will give this a shot on my spare TG16 and if that succeeds do it on my main one. Thanks Keith!

[SignOfZeta]

Nice! I have a long weekend coming up. I really need to do this.

[NightWolve]

Thanks Keith! Awesome! I'm gonna do it for sure, was toying with the idea, but now having full/clear information, I think it'll be another fun project to do having already done the cap replacement on my Express! Oh, if you can sell me all the parts, that'd be cool! If you got extras!

[YAGRS]

Question from someone who isn't very tech savvy—will this work with the Turbo CD? If not, has anyone come up with a solution for getting S-video from a Turbo CD?

[thesteve]

from the cd base it can be done with an encoder, but not this way

[YAGRS]

And that, in all likelihood, is beyond my abilities at this point. Maybe someday.

[Keith Courage]

There is no reason to put an S-video jack in the CD base. Installing one in the turbografx system itself would be easiest and will work for both chip and CD games. You would just want to use the CD base still for the audio.

[ApolloBoy]

After having done this mod to a couple of PCEs, I've found that 220 ohms is the "sweet spot" for the resistor on the luma amp. Part of my reason for selecting it was because I didn't have any 200 ohm resistors on hand and because I wanted to try a higher value. It's been tested on three different TVs (two Sony PVMs and a big Toshiba CRT) and looked fantastic on all three. I was amazed at how great it looked on my friend's 20" PVM, it looks very close to RGB!

[NightWolve]

Hm, you pretty sure about that 220 ohms? Sucks about the uncertainty here, but if you say 220 Ohms is the "sweet spot," I'm inclined to use it.

Keith, I take it you're not interested with the idea of s-video mod packs, selling everything needed ready-to-go ? Wanna put my order in with DigiKey if not. BTW, in general, is DigiKey the preferred retailer around here for electrical components ?

[YAGRS]

There is no reason to put an S-video jack in the CD base. Installing one in the turbografx system itself would be easiest and will work for both chip and CD games. You would just want to use the CD base still for the audio.

Okay, this is what I was wondering. I didn't know if the CD video had to come out of the CD base or not. If I can mod my TG-16 for S-video, connect the CD base, and use the S-video for both, then I'm going to try this mod.

[BlueBMW]

Hm, you pretty sure about that 220 ohms? Sucks about the uncertainty here, but if you say 220 Ohms is the "sweet spot," I'm inclined to use it.

Keith, I take it you're not interested with the idea of s-video mod packs, selling everything needed ready-to-go ? Wanna put my order in with DigiKey if not. BTW, in general, is DigiKey the preferred retailer around here for electrical components ?

I typically use mouser but also ebay for odd things like logic chips.

[bust3dstr8]

What about using trimmers? Use a 0.5K and dial it in until you get the best result.
There are vary small ones made that are not much bigger than a resistor.

[futureman2000]

Did this mod today, it looks fantastic! Looks way better than composite, which isn't that bad to begin with on these consoles. Also, it was nice to get the plug all on the back of the console... no more goofy av cable coming out of the left side! I didn't try any other resistor values- 220 seems just right.

[NightWolve]

Thanks to futureman2000, I stopped by my local Radioshack and was able to find all parts needed except a female s-video mount which I guess I gotta buy online. But during my visit, I ran into something interesting. Apparently, RCA/Composite-to-S-Video adapters already exist. Has anybody ever tried these ? I mean, if it's possible just from the composite signal, why wouldn't a good quality TV already better process the signal ? Here are the items in questions:

Bidirectional RCA-to-S-Video Adapter
"This Cables To Go™ RCA-to-S-Video Adapter is an alternative to costly active converters. The Y/C signal separation circuitry provides a crisp picture, perfect for your multimedia setup."
http://www.radioshack.com/product/index.jsp?productId=2486496

Expensive one (This is the one I saw at the store):
http://www.radioshack.com/product/index.jsp?productId=2102651

thesteve, what do you think about these?

[thesteve]

a good set will do T least as well........probly better
the color sig punches holes in the luma sig when mixed

[NightWolve]

https://www.jrok.com/hardware/RGBv4/index.html




Hmm, anybody by chance know anything about this encoder, does it work with a TurboDuo ? I'm wondering now if I should give this a shot, go all the way, not just s-video (I noticed that new LCD TVs stopped supporting it, it's down to Composite, Component, VGA and HDMI these days)... The guy wants you to email him for a price, so I'm guessing he gives a "special price" per customer... ;) Anyhow, I'm somewhat interested if the price is right and if it works.

[thesteve]

how would that help you
the duo has better composite than that thing can possibly do.

[NightWolve]

??? The Component output converted from raw RGB via this circuit is worse than the native composite output ???

[thesteve]

err no the component is good if your display does 240p

[Keith Courage]

Most new LCDs will still take a composite source. It's just not what you are used to seeing. You just need one of those stupid adapters for them. I had to track one down for a friend not too long ago. I mean, how much money are they really saving by not just putting RCA jacks on the TV for you instead of that 3.5mm port?

[thesteve]

lol its real-estate not money
thats what i use on the express

[Keith Courage]

Oh, by all means that makes perfect sense to use it for an express since space is limited. But inside a LCD TV or plasma there is plenty of room. Not to mention if you are throwing down $500-$1000 on a nice TV don't you think TV manufactures could put/build in some composite RCA jacks for you.

[thesteve]

they dont want to remind you its just a tv

[grahf]

Those jrok encoders have been around for a long time, and don't seem to work with PCE stuff for some reason. Not sure if anyone ever got one to work, but there are cheaper RGB to Component options out there.

[NightWolve]

Yeah, you're right, grahf... Bad idea. I asked him about it to be sure:

I have sold at least one in the past for use with the TurboDuo, but they also used one of the sync-cleaner boards, I don't know if it's required to be honest as I've never tested it myself.
From a quick read about the if the sync is very low level, then the encoder may not be able to detect it at all. Also the issue of low RGB levels output from the Turboduo sounds like it would almost certainly need an additional video amp, which the board does not include.

He wanted $50 bucks for the RGB-to-Component-only version BTW, but if you have to play around with an Amp and need this "sync-cleaner", with that level of uncertainty, it's not worth it... I'm the last person that would be able to figure it out. I guess you gotta go with those external devices you see floating around eBay.

@Keith: Yeah, the ones that I was looking at had regular Composite RCA jacks, they didn't have S-Video, though. They're not bothering with S-Video is what I was pointing out - it seems that connection standard might be on the way out with newer TVs.

Anyway, I'll just do the S-Video mod for now. Spent about $5 bucks so far, minus a female S-Video mount which I still need to find.

[Kidpanda]

What about using trimmers? Use a 0.5K and dial it in until you get the best result.
There are vary small ones made that are not much bigger than a resistor.

yea i would think this would be the way to go

[Kidpanda]

What about using trimmers? Use a 0.5K and dial it in until you get the best result.
There are vary small ones made that are not much bigger than a resistor.

yea i would think this would be the way to go

[Duo_R]

man I saw a few initial posts in this thread but missed the rest...lol! Nice work TheSteve and others (like Keith)!

I have Component video in most of my Duos, but I do have one that I would like to have Svideo on. I always intended to do the CXA1645 mod but just never got around to doing that. Now Drakon has done basically the same circuit but removed a resistor on the board, I wonder how that changes the picture compared to the way the rest of you have done it?

http://www.jrok.com/hardware/RGBv4/index.html

Hmm, anybody by chance know anything about this encoder, does it work with a TurboDuo ? I'm wondering now if I should give this a shot, go all the way, not just s-video (I noticed that new LCD TVs stopped supporting it, it's down to Composite, Component, VGA and HDMI these days)... The guy wants you to email him for a price, so I'm guessing he gives a "special price" per customer... ;) Anyhow, I'm somewhat interested if the price is right and if it works.

As far as component converters go I have had good luck with the Atlona RGB to YUV converters. As others have mentioned the Neobitz didn't work so great on the Duos. Nice work



Got a couple of these off ebay for about $45.

[HercTNT]

You have component "in" your duo's????

[Duo_R]

Well RGB amps internally to a modified AV port sends RGB to the Atlona box which converts Tje RGB signal to  component video. So it isn't internal although I could internalize if I wanted to.

[pdiggitydogg]

I just made a diagram to help those of you out who want to upgrade your video to S-video. Especially since I was confused myself when I first did this without seeing any pics. There is also info on where to tap the needed signals for both a DUO system or a standard TG16/pc engine.


https://postimg.cc/qN0JrWD8

Sorry to bring this back from the dead, but does anyone have this diagram from Keith?

[SmokeMonster]

I'd love to have the diagram too if anyone has it saved.

[Keith Courage]

I didn't realize it was down. Uploaded it again here. Also, I have found that for a US Turbo DUO or Black PC engine DUO it is best to get ground from the AV port. Tapping it from the sheild or common ground on the board itself doesn't produce as clear of an image. There is also another good place to get 5V and Pin 40 for the collector straight from the Hu6260 chip inside a DUO that I like to use instead of the AV jack now but the AV jack still works just fine. It's just personal preference where to tap some of the signals from.


https://postimg.cc/qN0JrWD8

[NightWolve]

Steve's suggestion for the best place to ground your video circuit is right at the Huc6260 chip itself which would be pins 55+56. Are you suggesting otherwise in having tested the AV port versus pins 55+56 ? Also, best undisputed tap for a 5V source is the output pin for the regulator. Clean voltage right from the source not having gone past many traces to get to the AV port or wherever else you might tap it.

[Keith Courage]

Yeah I've tried the two pins mentioned off of the hu6260 for the ground. still produces a slightly blurry image with a US duo on my TV. ground from the AV jack is the only place that seems to fix the issue. I've tested it with many US DUOs. I would also like to add that tapping the av jack ground fixed issues with the component video mod showing big white lines as well on US and JP Pc engine DUOs.

Could just be an issue with my TV as well.

However, I've been able to use any ground for a turbo grafx, white pc engine, and duo-r without any issues at all.

[thesteve]

the prob is the ground on the AV jack of the US duo
run a wire from AV ground to 6260 ground

[NightWolve]

Hmmmm, thanks for info then Keith... Guess I have to work this info into my photo guide somehow... :/

[existensmaximum]

yes the chroma could be cleaner (its from pin 20 inverted)
the cap cleans the signal (smaller cap cleans it more)
i just used a cap and transistor i had handy

Hello! I'm doing this mod soon, and I have a couple of questions first.

1, Earlier in the thread, you said that any NPN transistor will do. Is that true? Any? Could I try with any NPN I have lying around at home, or could I damage something..?

2, Would an even smaller cap clean the signal more? I would need to buy this capacitor anyway so I could just buy an even smaller one than 0.001 uF. Same question here - could I damage anything by choosing the wrong value?

[thesteve]

Yes any NPN you have should work
The cap I stated should be the smallest  you can use