As I was attempting to do this mod myself, I could not find a single complete guide for getting vga to work using the xboxes internal sync signals. So to help anyone who can't afford a HDTV or a xbox 360, here is my guide.
this guide is not for the faint of heart. as with every modification to the xbox, there is a risk of totaly fucking it up. I take no responsibility for what YOU do to your xbox.
this mod requires fine soldering. if you don't have a soldering iron, don't bother. you should have previous SMD soldering experience.
now. what exactly will this mod achieve? well it will get you an xbox that will work with almost all VGA screens and projectors. it will give you the best VGA signals possible with the xbox. the only nonstandard aspects of the signals will be a high rgb signal voltage, a low sync voltage (2.6V) and the sync signal will still be embedded in the green signal. basically the signal will be within spec for most screens but some really picky ones might not work. so far it has worked for every monitor i have tried.
you should not bother this mod if you have a monitor which supports sync on green or SOG. if your screen supports SOG all you need to do is build a cable and install a vga bios
OK here we go.
What you will need:
-a modded xbox. tsop, modchip or even softmod
-any xbox AV cable
-a VGA cable
-some fine insulated wire (the finer the better. enameled copper winding wire would also probably work, for connecting to the tiny points on the board)
-some not so fine wire (like from a IDE ribbon cable out of a computer, this is for power and the external wire)
-a Schmitt trigger chip like the 74hc14
-a 330ohm resistor (or whatever gets you 2.5V to 2.65V. its just to load the diode)
-a 1nF capacitor
-a 10uF capacitor (optional for extra filtering. anything bigger will do)
-a diode (any silicon diode will do. I used a 1N4003)
-a small 2 pin plug and socket
you will also need these tools
-torx screw driver to open the xbox
-a soldering iron with a fine tip and some thin flux cored solder
-skill with the soldering iron. this is important!! if you can't solder give up now. you are required to solder to 2 tiny points on the motherboard.
-a sharp hobby knife
-wire snips
-a multimeter
The following is a schematic of the circuit I made for my xbox
(IMG:
http://i197.photobucket.com/albums/aa189/yaywoop/vgaschematic.jpg)
The main difference between my idea and that on xbox-linux.org is that I am running it off 2.6V, not 1.5V. This works because at 2.6V Vcc the 74HC14's trigger is just below 1.5V.
The diode is there to drop 3.3V down to 2.6V and the resistor just keeps a slight load on the diode.
This is how you actually put the circuit together, it should be pretty self explanatory.:
(IMG:
http://i197.photobucket.com/albums/aa189/yaywoop/everythingelse.jpg)
I give credit to sandman1867 for the motherboard sync points photograph. the rest are mine.
When soldering the points on the motherboard it is important to get a good join. First it must be carefully scraped with a hobby knife to get the green gunk off. I say carefully because it is possible to cut the track.
I used a very fine tip and a tiny bit of solder with flux to tin the connections before i soldered on the wire.
After you soldered the wires on, test for continuity between the wire and the corresponding pin on the encoder chip:
(IMG:
http://i197.photobucket.com/albums/aa189/yaywoop/encoder.jpg)
Alternatively you can just solder the wires directly to the encoder chip. but you run the risk of bridging pins. Only try this if you know what you are doing and have very thin wire and a ultra fine soldering tip
here is a photo of my final mod:
(IMG:
http://i197.photobucket.com/albums/aa189/yaywoop/finalvgamod.jpg)
The wire running down the bottom of the photo is going to the power connector for 3V
The 2 white wires running out the top is going to the cable.
Here's a pic of the cable:
(IMG:
http://i197.photobucket.com/albums/aa189/yaywoop/DSC00711.jpg)
I am not going through the details of making a VGA cable, this has been covered before.
My cable is basically a copy of Frosty's cable but without the sync separator (because the sync is coming from the xbox duh) I just used a VGA cable and ran the audio through the unused wires (usually used for identifying the monitor)
However you need to find the sync wires in your VGA cable and figure out a way to connect them to the sync wires now coming out of the xbox. I just used a 2 pin connector I had lying around. You can see the connector poking out the back of the xbox. poor i know but it works
That just about concludes the howto. sorry about the lack of detail. If anything isn't clear please tell me
This post has been edited by Foe-hammer: Oct 25 2007, 01:37 AM
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Topic: Vga Internal Sync Mod Howto (Read 237 times)