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Vga Internal Sync Mod Howto


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#1 yaywoop

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Posted 03 October 2007 - 02:56 AM

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
IPB Image
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.:
IPB Image
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:
IPB Image
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:
IPB Image
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:
IPB Image
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

Edited by Foe-hammer, 25 October 2007 - 01:37 AM.


#2 yaywoop

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Posted 03 October 2007 - 03:29 AM

oh and you will also need a VGA compatible bios
like Frostythesnowman's. which will work with every game.
this will also work with xbox-linux using the cromwell bios. but cromwell recognizes avip mode 1+3 as vga

Edited by yaywoop, 03 October 2007 - 03:43 AM.


#3 FrostyTheSnowman

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Posted 03 October 2007 - 04:33 AM

I'm doing this mod for sure.

I just got a new dremel, so I think it's time I finally mounted a VGA connector on the back of my XBOX. biggrin.gif

Thanks again yaywoop!

#4 yaywoop

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Posted 03 October 2007 - 04:48 AM

your welcome smile.gif . is there any way to edit a post? the edit button disappeared.

mounting the vga connector on the xbox is very practical for this type of mod. i probably should have included pinouts for the AVIP and VGA sockets

#5 joesnose

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Posted 03 October 2007 - 09:16 PM

niceone yaywoop, you probably should put a vga connector, look better than those two wires.

#6 yaywoop

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Posted 04 October 2007 - 12:13 AM

hmm I screwed something up with this tutorial. although it doesn't really make much difference
the voltages. its not 3V at the power connector its 3.3V and the Vcc voltage for the 74HC14 turns out to be 2.65V. which still works. if you can find a Zener diode of 2.4V that would be a better option. or a linear voltage regulator. if not don't worry
so when you are checking what the voltage is at the 74hc14, it should be around 2.6V

and just in case you didn't see in the "how to actually put it together" diagram. its pins up. because I just freeformed it.

yeah i know that the connector isn't really very neat, but I couldn't be bothered taking out my motherboard and drilling holes in the case at that time. also I don't have a dremil

anyone know how to edit a post after the edit button has disappeared?

Edited by yaywoop, 04 October 2007 - 12:23 AM.


#7 hartigan

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Posted 17 October 2007 - 04:58 PM

yaywoop,

First off, thanks for this great tutorial.

I'm wondering whether this method is better than or just different from the internal sync method mentioned on www.xbox-linux.org


Mostly just curious.

Thanks!!



#8 yaywoop

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Posted 20 October 2007 - 01:04 AM

well its an improvement on the xbox-linux one smile.gif
you may notice that the only difference is the voltage for the triggers. i changed the voltage because 1.5V wasn't working for my vga screen.
I just thought i would post an actual build. because i don't think any one else has.

btw; its definitely not the most popular or easy method of getting sync signals, but its the cheapest and its gets very good results.

#9 hartigan

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Posted 13 November 2007 - 02:55 PM

Are points 35 and 36 for the HSync and Vsync going to be in the same spot on the motherboard for xboxes with the focus encoder?

If not, do you happen to know where they would be for the v1.4 xbox?


Thanks for all your work with the tutorial. It's very well written and ez to follow.



#10 FrostyTheSnowman

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Posted 14 November 2007 - 01:19 AM

QUOTE(hartigan @ Nov 13 2007, 08:31 AM) View Post

Are points 35 and 36 for the HSync and Vsync going to be in the same spot on the motherboard for xboxes with the focus encoder?

If not, do you happen to know where they would be for the v1.4 xbox?
Thanks for all your work with the tutorial. It's very well written and ez to follow.


They should be in the exact same place on the v1.4 motherboard too. happy.gif

#11 yaywoop

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Posted 15 November 2007 - 12:04 PM

Thanks biggrin.gif
I am glad you like it
yeah i am pretty sure it is the same on all chips but the V1.6

#12 mcbeat

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Posted 24 November 2007 - 04:35 AM

i dont get it blink.gif

how is this different from what frosty did? is this a inside version rather then a outside version
OR
better for monitor compatiblitly?

what this does is says we dont need one of these
http://www.maplin.co...e...o&U=strat15
the
LM1881N Video Sync Separator

or am i just on the wrong path here?

great guide by the way,

Edited by mcbeat, 24 November 2007 - 04:35 AM.


#13 yaywoop

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Posted 15 January 2008 - 02:26 AM

Yeah, this mod is an alternative to the LM 1881 design. It gives better compatibility because it gives true sync signals

See here for some info on different methods for vga on the xbox http://www.xbox-linu.../Xbox_VGA_HOWTO

#14 Szamot83

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Posted 06 March 2008 - 08:56 PM

I've done this in This way:
IPB Image
IPB Image

Tomorrow i'll check if this mod work. I hope that it will. I have problem with bright and contrast on my monitor. Maybe this mod will help.


#15 yaywoop

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Posted 09 March 2008 - 04:12 AM

looks nice. how did it go?
by the way, i think the colour problem you mentioned is because of the low voltage of the analogue signals (the RGB signals) and some monitors don't like it. so i doubt propper sync sygnals will help (assuming you where using sync on green before?)




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