VGA output in Xbox

[MrMajst3r]

Hi I want to add VGA output to my Xbox. I've read about 2 methods:
- Hsync, Vsync from LM1881N
- Hsync, Vsync directly from video encoder

Which way will give better video quality? Has anyone tried it?
On Xbox-Scene forums I've found that 1st method works almost for everyone, but with 2nd people has problems.

[professor_jonny]

You have to really use the sync seperator chip as the xbox decoder output is not buffered and the sync signal can mess with the green phase and cause issuies with your monitor also you risk overloading, i believe you may kill your xbox video decoder chip in time.

You can also buffer the xbox output with a 74ls buffer or something simular along those lines.
it is actually best to buffer the sync output from the sync seperator chip if you plan to use long cables to your tv/monitor.

The other option is component and a vga box or a computer screen with sync on green most sony tv's/monitors support sync on green there is a big list on some playstation web page as sony was a big pusher of sog for use with their playstation's and tv's.

I my self use a neoya x2vga2 adaptor.

[asbo]

I've messed around with this a lot over the years and, assuming your monitor isn't sync on green*, its so much easier to buy a Component to VGA box.
This is the one I have, but search around as they may be cheaper elsewhere.

*What model monitor do you have?
Sometimes the manual says nothing about sync on green, but it works. This is the case with my Benq G2222HDL

[MrMajst3r]

I do not want any converters... I just want VGA mod

I consider using this diagram with direct singnals and 74HC14 (but some people wrote that doesn't work)
http://forums.xbox-scene.com/index.php?showtopic=624248
or LM1881N
http://forums.xbox-scene.com/index.php?showtopic=213487

So I'm asking if you have any experiences with these mods?

[2 Bunny]

Bear in mind (so you don't make my mistake) that component and VGA, however alike they may seem, are not the same. I now know that you can't just feed the "Y" into "Green", the "Pb" into "Blue", and the "Pr" into red. They have to be somehow converted, and as such the Xbox at the house now only hangs out at Component friendly displays.

- 2B

[asbo]

I've used a LM1881N before, but with a PS2 rather than an xbox. I didn't have much luck with it. The reason was that, even though it took the sync signal from the green channel and converted it into Hsync and Vsync for VGA, it left the sync signal in the green channel and some monitors don't like that. I got a purple screen on one monitor and scrabbled rubbish on another. The solution was to incorporate a sync stripper into the circuit to remove the sync signal from the green channel, but I never got it to work.
Of course doing all of that you are basically building a converter, so you may as well buy one.

I do not want any converters... I just want VGA mod

The thing is as soon as you start adding any circuitry its not "just a VGA mod" any more.
The only way to get "just a VGA mod" would be to use a VGA cable with a monitor that supports Sync on Green.

[professor_jonny]

yip i forgot that asbo the sync can make the screen go green if the screen does not like the sync signals, but in theory it shuld not make an ounce of difference as it should just skip or ignore the sync as it shuld be out side the display data, basically it is poor design readding the sync as green data.

You can remove the sync from the green component to be compliant with those displays but propagation delay may ruin you day it may not and really were talking of making a pcb here.

What you would do is get the green component and strip the sync using the lm1881 then feed both outputs of the seperated sync h and v and preform a logical NOTAND with the green component signal then feed the two outputs into an OR gate and it would strip the sync from the green and give you a clean green signal for your green component output as well as both clean h and v signals.
problem is they have different voltage references.

This will most likely add propagation delay that would cause the green to lag the other component signals and you would have to use aditional gates to delay or make the green component be back in sync with the other component signals you could try to make the green lead shorter or try wrap the other two components through a ferrite inductor (thats if it works).

people with skills (not me) would just slap in a clpd and program it to do as they wanted which is basically what a vga box is.
http://www.syncblaster.com/SBBOX.html
http://www.inlineinc.com/products/special/2065.htm