S-Video on PSOne Screen. You can't do it..

segasonicfan · Post by **segasonicfan** » Sun Jul 31, 2005 7:28 pm

Editing note: read through post, it doesn't look like it's possible.

I've been doing a lot of research on my PSOne screen the past couple days in an attempt to reduce its power consumption. I've finally uncovered the only part of the system that actually uses the full 7.5v power supply and that's the AN2526NFH circuit. I believe everything else runs off 5v since that is how the audio amp and cathode tube are powered...
but anyway onto the S-video...

http://users.raketnet.nl/darkfader/=%3E ... 526NFH.pdf

That's the PDF of the circuit and as you can see, it supports Chroma and Luma inputs for S-Video. Looking at the PCB layout it's connected in the analog RGB fashion and uses other circuitry to detect a composite input. Therefore it is NOT connected to composite on default. So it looks like S-Video will work if you simply connect Chroma to pin 51 and Luma to pin 60! I haven't tested it yet but it all seems pretty straight forward. Those two lines are combined for composite input (duhh that makes sense), so when seperated it should output S-Video!

Also, for those that remember Ben's brightness mod this datasheet explains it. He removed the cap to the luminance clamp input. And that lead to increased luminosity!

This should be extremely useful info to those of you working on portable N64s out there.... =)

-Segasonicfan

usbcd36 · Post by **usbcd36** » Sun Jul 31, 2005 8:38 pm

Yes, but my N64p is just going to use RGB. You mean this will be a boon to those making VCSps.

segasonicfan · Post by **segasonicfan** » Sun Jul 31, 2005 11:54 pm

oh you did an n64 RGB video mod then? You must have one of the older boards with the RGB lines available. I tried hooking mine up directly, but the the signals made the picture too dark. I'd love to know how you did the mod for it...

Also, I'm going to try to do a component input on my PSOne screen. That way I can watch DVDs on my Portable PSTwo without having to use crappy composite. Unfortunately I know very little about component video so I'm doing some research on it right now.

-Segasonicfan

segasonicfan · Post by **segasonicfan** » Mon Aug 01, 2005 4:22 am

SUCCESS!! After a couple hours tinkering and looking over the schematic I managed to output full S-Video. And the quality is WAY better than composite! This is good news for Atari makers and those with DVD players with macrovision (like the PS2) =) What I'd really love to do now is get component video working on this but that's gonna be hard....=/

-Segasonicfan

*o* · Post by ***o*** » Mon Aug 01, 2005 4:29 am

great work!!! I am so impressed ny this!!!

tom61 · Post by **tom61** » Mon Aug 01, 2005 3:01 pm

Good to know it does take S-Video, I'll be passing that info along. Can you take pics to help out the newbs in figuring out what to do?

I'm disappointed that the one component that needs >5V is the hardest to replace and have the screen continue to work. Powering the screen off 5V would be great for PC mods.

segasonicfan · Post by **segasonicfan** » Mon Aug 01, 2005 3:37 pm

Just finished taking the pics

It's a pretty simple mod to do and I made the pics self-explanitory:

Just disconnect that one side of the cap. This disconnects the chroma and luma inputs from eachother.

Connect Luma to the Composite signal in. This will switch it out of Analog RGB mode (I believe it detects the Sync line).

And voila! Ground your S-video (obviously) ans you're good to go =)

-Segasonicfan

usbcd36 · Post by **usbcd36** » Mon Aug 01, 2005 3:48 pm

segasonicfan wrote:oh you did an n64 RGB video mod then? You must have one of the older boards with the RGB lines available. I tried hooking mine up directly, but the the signals made the picture too dark. I'd love to know how you did the mod for it...

I didn't actually do the mod yet, I'm still waiting for the white LEDs so I can safely have my PSone screen sitting on the carpet (and not have it catch fire). Is there a certain model you need to have for the RGB? I didn't know that. Also, you should have some 200?F caps between the N64 and the PSone screen, as I'm told. It is supposed to lighten the picture or somethingâ€¦

segasonicfan · Post by **segasonicfan** » Mon Aug 01, 2005 4:10 pm

You have to have an early N64 board from 96 or 97. Later boards don't have RGB output... =/ That's why the S-Video mod can be very useful to N64 people. It's very hard to get an early board since there is no way to distinguish the boards outside of the case...you just have to open it up. And as for the mod, you need more than 220uf caps. It requires a video amp NPN Transistor for all RGB and Sync lines and some other passive components.

-Segasonicfan

segasonicfan · Post by **segasonicfan** » Mon Aug 01, 2005 4:15 pm

Can someone help me out with the Component mod for the PSOne screen? This would be an AMAZING mod for any PS2 due to all the anti-RGB crap Sony has. The Y connection works perfect (just connecting to Sync line) but the R-Y and B-Y inputs aren't working. I also got a -5v readout on them which seems a little high to me. I think the chip might need to be told to switch to Component mode, but I can't figure out which pic controlls the video mode... =(

-Segasonicfan

usbcd36 · Post by **usbcd36** » Mon Aug 01, 2005 4:24 pm

segasonicfan wrote:You have to have an early N64 board from 96 or 97. Later boards don't have RGB output... =/ That's why the S-Video mod can be very useful to N64 people. It's very hard to get an early board since there is no way to distinguish the boards outside of the case...you just have to open it up. And as for the mod, you need more than 220uf caps. It requires a video amp NPN Transistor for all RGB and Sync lines and some other passive components.

-Segasonicfan

Mine is from '96, or so it appears. Also, according to the video mods in the sticky here, the RGB signal is fairly strong when acquired from the chip instead of the resistors. I am not sure if you do, in fact need the caps, since the PSone will not output good RGB without them either and the screen will accept that.

segasonicfan · Post by **segasonicfan** » Mon Aug 01, 2005 7:11 pm

Well I tried the RGB N64 mod myself a while back and the signal is not strong enough even directly from the chips. According to www.gamesx.com the PCE rgb amp is the most suitable.

-Segasonicfan

segasonicfan · Post by **segasonicfan** » Mon Aug 01, 2005 7:50 pm

oh and is it turns out the screen switches to composite/s-video mode simply when the video input (detection line) is connected to 5v. So you don't even have to connect luma there =)

EDIT: Actually this doesn't work. Luma carries the Sync signal which is split using a LM1881 Sync Seperator. Therefor you won't get any video unless you input luma or some other sync carrying signal here.

-Segasonicfan

Post by **Gamelver** » Tue Aug 02, 2005 3:56 pm

well, I just finished the s-video mod on my psone screen, tested it with my N64, and it worked

!!! good job on creating the mod, segasonicfan

!!! now then...onto the rest of my N64p4!!!

usbcd36 · Post by **usbcd36** » Tue Aug 02, 2005 6:10 pm

I still can't tell if I have RGB on my N64, how can you tell? I have hooked up the wires to the chip on the system, and it still works with composite (so luckily, I didn't fry it or anything), but I don't know how to hook it up via RGB.