Full VGA Support For Modchips!
Posted 22 September 2007 - 01:48 PM
RGBCV ---> RGBHV
CVH (csync,vsync,hsync TTL-Level)
h-sync has to be high if c-sync high and v-sync low
Now, if we use 7400 (four NAND) we may get h-sync (I dont know if the 7400 is fast enough).
- From LM1881 put c-sync and v-sync to the first NAND.
- The output of the first NAND and c-sync to the second NAND.
- Put the output of the second NAND to the third NAND (to invert the signal).
- The second NAND and the third NAND as intverter then build a logical AND.
at the end of the site for the circuit.
The LM1881 and 7400 are easy to get in many countries by private purchase.
This may be the solution to get hsync and vsync without the internal sync signals of the XBOX.
I am not sure but I think some very old Sun and Apple monitors need the c-sync instead of h-sync.
Excuse my poor english.
Posted 26 September 2007 - 01:56 AM
it would probably be a good adition to the frosty vga cable, or a mod for people who need it.
i am sure there will be room inside the box
the only place i can get a lm1881 is over the net. and i cbf, so i will stick with internal signals
Posted 03 October 2007 - 11:26 PM
Punmaster: I appreciate the explanation of the "video level corrector circuit", and am trying to build one, but the "break the three "discharge” traces and wire them instead to the three negative (inverting) inputs of the op-amps" direction doesn't show up on the schematic you posted (linking pins 1 to 16, 3 to 4 and 6 to 7, I'm assuming), though I've tried both and neither seem to work (the schematic first, then the rerouting of discharge traces). The fault could be due to my human error, but some clarification would be great.
Posted 04 October 2007 - 12:57 AM
so you have the evaluation board?
I didn't realize punmaster achieved this. using that circuit and the internal vga mod its possible to get *completely* standard vga out of the xbox
I wonder if the MAX4383 could be used instead of the LMH6739
unfortunately punmaster hasn't logged in for a month or so
hey frosty. did punmaster ever complete his ultimate tutorial? I was thinking about writing one but i quickly gave up
Edited by yaywoop, 04 October 2007 - 12:59 AM.
Posted 04 October 2007 - 01:20 AM
I honestly can't remember.
If you look back in this thread you will find out more about it, but I don't think he ever officially released his diagram...
Man, native VGA sure is a pain in the ass on the original XBOX...
Posted 04 October 2007 - 01:41 AM
its annoying. I did that internal sync mod and a few days ago I got a LCD that supports SOG.
yeah i found the post where he explains it
I think its pretty good that we can get any VGA output on a console that wasn't supposed to support it with such little hardware
Edited by yaywoop, 04 October 2007 - 01:45 AM.
Posted 04 October 2007 - 09:19 AM
I have not really done anything much with analog circuits before but tell me what your problem is and I might be able to help you
Posted 04 October 2007 - 10:18 AM
however I did notice the white tint on both of my CRT screens. so I will attempt the RGB level corrector anyway. it looks really easy.
I was going to make a transcoder with these max4383's but I can't find the resistors for it. maybe I will just make a level corrector and VGA switch all in one instead
Posted 10 October 2007 - 04:44 AM
When the discharge traces are wired to the respective inverting negative inputs, the screen blanks out as well upon testing, with or without power.
The power seems to be fine, measuring at 5 volts steady.
The vga ports are also wired correctly, and work when the circuit is bypassed.
I might try replacing the chip.
Posted 11 October 2007 - 05:33 PM
Posted 12 October 2007 - 03:26 PM
you are not supposed to spit this particular X2 bios into 256 anyway.
Posted 12 October 2007 - 03:51 PM
Posted 13 October 2007 - 02:04 AM
Optionally, you an also try another utility called 'Simple xISO' to extract the files from the ISO.
NOTE: Whatever you do, DO NOT flash this PBL BIOS to any modchip.
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