Input S-Video to your PAL psone screen (Images Fixed)

If you're making a portable you probably need something to watch it on. (Unless you want to guess what's happening in the game, but I wouldn't advise that) Anyway, this forum is your "Hacking a pocket TV/screen" one-stop solution. Share your experiences and knowledge here.

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sam_thornley
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Input S-Video to your PAL psone screen (Images Fixed)

Post by sam_thornley » Fri Aug 10, 2007 5:09 am

I wanted to get better picture quality on my portable (The Sega Game Block) because i was sick of using composite as it sucks ass.

I was tracing around were video signals go an the board and i came across this philips chip the doesn't seem to be present on NTSC screens. I probed around the chip with the oscilloscope wile inputing composite video the normal way and noticed that it was outputing a pure chroma signal through to the AN2526NFH chip. And on another pin it was outputing a luma signal. Then i got the idea that i could input a s-video luma signal in to the composite input and then input a s-video chroma to where the philips chip outputs to the AN2526NFH ciruit. Still with me ?!
(i bet your thinking now "i've heard this all before on segasonicfan's post its not posible!" but it is with a PAL psone screen as the video circuit is slightly differnt to a NTSC version) I tried it...first the picture was just
black and white as i hooked the chroma up to the wrong pin. Secondly i hooked the chroma pin 51 on the AN2526NFH then picture was in color but it looked like i was inputing composite like before. Lastly i removed a smd capacitor and conected a 220uF cap to 51 and inputed chroma through the cap. It worked awesome! The picture quality had improved loads!

There where...

No more Cross color artifacts

No more Colour bleeding on reds and blues

Sharper image!

If i even dare say...the quality is compareable to RGB!

Its seems that the AN2526NFH is set by an I2C bus to natively accept luma and chroma signals on PAL versions of the psone screen. I'm probably wrong but i'm saying this because of the quality of picture i'm getting is decent. It might be still mixing the y&c signals internally (like on segasonicfans post) but in way that the picture quality is not affected.

How to do it your self.

Basicly conect your Y (luma) signal to the composite in the usual way and
your chroma like this...

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another view...

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If you want any high resolution pictures of the board i'll be more than happy to take some more!

I hooked up my s-video moded radica genesis/megadrive back up to the psone screen so i can put every thing back in to the case. Heres some pics of the psone screen using s-video on a my radica...

Radica ver2 menu...the colors are a bit high but it could do with some more tinkering...

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Alex kidd...look at the text its solid yellow! no cross color! My camera isnt the best so this this is the best pic i could get.

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Alex kidd...level 1

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Radica version 1...hooked up using svideo

Dr.robotnicks mean machine...Pixel perfect!! (almost)

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If you have a PAL screen try it! its loads better than composite!
Last edited by sam_thornley on Thu Apr 30, 2009 4:56 pm, edited 2 times in total.
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Felino
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Post by Felino » Fri Aug 10, 2007 7:11 am

Wow, this should be stickied, great work man!
Charlie wrote:I always wanted to try wall flips, but I'm too attached to my neck.
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bacteria
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Post by bacteria » Sat Aug 18, 2007 3:45 am

This is truly top-grade stuff, excellent work, really well done.

Would you be able to use this mod in a system which inputs BOTH composite (for one system) and RGB for another system (switchable systems) or would this lead to problems (eg missing smd capacitor)? I presume the smd capacitor comes off easily with a little desoldering braid?

Could you please give a final (large, unreduced) pic of the PSone mobo in its final state after your mod?

Excuse me if these questions below seem a bit daft, but I haven't fiddled with S-video much before, so don't know as much about it as I would like:

If your system outputs composite (the standard yellow cable) into the PSone screen:

1) can you split this signal into S-video (if so, how - detail please).
2) would you get any benefit in terms of video quality from splitting composite into S-video (or would the fact the signal started as composite mean the signal is degraded already so making the signals S-video is not beneficial); or is this mod designed purely for a system outputting S-video in the first place.

Thanks. :P
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Post by jeroen » Sat Aug 18, 2007 7:36 am

Wow this is ace stuff. We could use more people like you. *bows*

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Kyo
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Post by Kyo » Sun Aug 19, 2007 5:01 pm

nice!

This would be totally useful if I wasn't too cheap to buy official screens.

oh well, my cheap third party screen only accepts RGB anyway...

Anyhow, nice work!

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Post by Kurt_ » Sun Aug 19, 2007 5:14 pm

Scanning through this I figured you were some noob who plagiarized someone's hard work. After further scanning, I realized this is original work. You should hope. This is a compliment.

As most systems are available in PAL/NTSC or just PAL, this could be a great help for us NTSC users. There's almost always a way to disable lockout chips with no/few ill effects. Doing so would allow S-video easily on the PSOne screen for NTSC users.

Great work.

Sticky this someone.
Hey, sup?

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Post by jeroen » Sun Aug 19, 2007 5:44 pm

Pal screens are ridiculously high price on ebay though. it'll rise if you start buying them :-(

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Kurt_
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Post by Kurt_ » Sun Aug 19, 2007 5:52 pm

In that case, I'll stick to RGB o my PSOne screen! :P
Hey, sup?

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Kyo
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Post by Kyo » Sun Aug 19, 2007 5:56 pm

precisely. I mean on ebay germany, there is ONE sony psone screen right now. it costs 70€, which is like 97$ (it's bundled to a psone tho)

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Post by jeroen » Sun Aug 19, 2007 7:14 pm

yup or that uk thing 70 for just the screen :-?

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bacteria
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Post by bacteria » Mon Aug 20, 2007 2:29 am

Kyo, most of the time brand new PSone screens are "buy now" only and cost about £35-£40 delivered (UK); however sometimes someone makes them auction; I got three PSone screens a while back on different bids, for around £26 each, delivered as I recall. It is all about how long you can wait for your screen as to what you pay.

On e-bay (.co.uk) at the moment, there is only one PSone screen, new condition, available, £40 delivered - not sure if he posts to Germany. Expensive, but they are hard to get after all now.
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Kyo
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Post by Kyo » Mon Aug 20, 2007 5:50 am

yeah, that plus shipping to germany, customs duty and I'm back where I started.

I'll just stick to my 3rdparty screens, they're cheap. (only) accept rgb, and the picture is okay too.

The only problem would be consoles that don't output RGB, but as I have posted in another thread, I'm currently looking into some ps2 screens which are relatively cheap.

I'm 16 years old, and this is a hobby. I just don't have 70€ for one screen.

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sam_thornley
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Post by sam_thornley » Tue Aug 21, 2007 12:08 pm

bacteria wrote:

Would you be able to use this mod in a system which inputs BOTH composite (for one system) and RGB for another system (switchable systems) or would this lead to problems (eg missing smd capacitor)? I presume the smd capacitor comes off easily with a little desoldering braid?

Could you please give a final (large, unreduced) pic of the PSone mobo in its final state after your mod?

Excuse me if these questions below seem a bit daft, but I haven't fiddled with S-video much before, so don't know as much about it as I would like:

If your system outputs composite (the standard yellow cable) into the PSone screen:

1) can you split this signal into S-video (if so, how - detail please).
2) would you get any benefit in terms of video quality from splitting composite into S-video (or would the fact the signal started as composite mean the signal is degraded already so making the signals S-video is not beneficial); or is this mod designed purely for a system outputting S-video in the first place.

So once you've done this mod you can only input RGB+Sync or S-video to get a proper picture. You can still input composite video like you could before but the picture will be in black and white as the split chroma signal from the composite has been disconected (by removing the smd cap).
Heres a unscaled picture of my finished mod...

http://s108.photobucket.com/albums/n19/ ... 010065.jpg

On my portable i use a megadrive radica that i modded to natively output s-video rather than composite. The radica used to output composite video but this post below shows you how to split the chroma from the luma on the PCB.

http://benheck.com/phpBB/viewtopic.php?t=18907

Composite video is made up of luma and Chroma signals of s-video mixed
together. Composite video can be split into s-video...google search "composite to s-video". Separating these signals if they've allready been
mixed will not improve the picture quality but make it worse. So this mod is purely for conecting up systems to the psone screen that only output S-video. If your system outputs only composite video (like the NES) then input composite video as normal to the psone screen to get the best quality. If your system outputs RGB use that to get the best quality of all! But Rember to add 220uf caps on each of the RGB lines.
Kurt_ wrote:

Scanning through this I figured you were some noob who plagiarized someone's hard work. After further scanning, I realized this is original work. You should hope. This is a compliment.

As most systems are available in PAL/NTSC or just PAL, this could be a great help for us NTSC users. There's almost always a way to disable lockout chips with no/few ill effects. Doing so would allow S-video easily on the PSOne screen for NTSC users.
Yes this is all of my own work :D , i've seen segasonicfan's thread but i still thought that s-video was posable on PAL screens only and it is! I may be new to these forums but i aint no noob!

I would recomend that NTSC users stick to RGB anyway as PAL psone screens are expensive to get hold of in the US.
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Post by Kurt_ » Tue Aug 21, 2007 12:38 pm

i aint no noob!
So you admit that you are? :P

RGB is superior to almost every other format of video signal. And most system CAN output it with/without a little modding. Just throwing it out there that RGB > S-video. I know some systems can't get RGB.
Hey, sup?

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sam_thornley
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Post by sam_thornley » Tue Aug 21, 2007 3:12 pm

Ok! forget the whole noob thing, i'm getting mixed up with Nob and Newbie!
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