Xbox VGA Bios modification help needed!

Discussion in 'Xbox (Original console)' started by N64 freak, May 24, 2016.

  1. ToxicMedz

    ToxicMedz Enthusiastic Member

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    720p seems to work fine with mine, I'm not seeing a black bar either.. at least nothing noticeable. Definitely has a issue with XBMC though, text has a green ghosting effect to it. UnleashX dash seems to look fine though as well as the games I have tried so far. Need to do more testing though.
     
  2. rso

    rso °

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    What's the setup you're using?


    Progress:
    - Better cable management got rid of the fuzzy hsync
    - Still no 720p. Fwiw, it does work with component. Can't check 1080i on the current monitor.
    - BG&E shows that squashed image even with component cables, maybe it just doesn't like being on an NTSC console? Anyways, doesn't seem to be a VGA issue. Have yet to come across a second game with the same issue, though I didn't check all that many tbh.
     
    Last edited: Aug 16, 2016
  3. ToxicMedz

    ToxicMedz Enthusiastic Member

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    Im using a X2 5032 vga patched bios, connected up to my 42" Vizio TV and aside from XBMC not looking good the video quality looks identical to my Frosty Frozen Vga cable or atleast very close. It does how ever cause me to have to change my screen boarders when switching between the two. I'd love to see what the black bar looks like for you because im not seeing it atm.
     
    Last edited: Aug 16, 2016
  4. rso

    rso °

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    I'll have to wait for some parts to come in until I can try the X2/5032 for myself, but I doubt the BIOS is going to make much difference anyways. What's your VGA mod - internal/external, w/ or w/o LMH1980?

    Re: Borders - Don't have a decent camera atm, but will try with my webcam. Of course I could enable/adjust the overscan settings like you seem to be doing, but to me that feels like cheating - overscan is for TV-type material, shouldn't be necessary for VGA. This mod falls into "hack" territory though, so I might just have to live with it.
     
  5. weinerschnitzel

    weinerschnitzel Spirited Member

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    Id recommend people test using Odamex and observing correct pixel aspect and overscan issues. If you are using overscan correction on your tv or on Odamex, check the mini map. Some walls will be omitted by nearest neighbor. If you have good overscan correction on your TV you wont notice anything.

    I had black bar issues with some monitors and the old lm1881n mod. I have a vga + toslink to hdmi adapter i will be trying with the lmh1980 and internal mod as the lm1881 isnt good enough.
     
  6. weinerschnitzel

    weinerschnitzel Spirited Member

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    Got my VGA boards from N64 Freak yesterday.

    I'm testing with a Connexant encoder, MrNova's VGA X3 BIOS and Frosty's and Xman's X2 5035. I'm connecting to a StarTech VGA2HDMI PRO.

    I'm experiencing a weird flicker with the External Mod. The screen will have a black frame flick on when I am navigating XBMC, or it will flick black every few seconds. Frosty's original LM1881 mod does not flicker here. The flicker also only occurs when I am using a VGA BIOS. If I use a standard AV BIOS, the screen does not flicker, however, the green tint is present.

    I'll wire in the internal mod when I get some time off work. I'll also test benny's VGA BIOS.

    The shielded lines give a superb picture. My overscan issues are also no more! Yay, Odamex minimap!

    With some more testing, I found that the Optical audio out and SPDIF out on the adapter are a little finicky. Optical works with XBMC but seems slightly quiet, and other games have no audio at all. SPDIF just gives me silence with some crackles. Not sure if the TOSLINK adapter isn't Xbox friendly, but SPDIF not working has me very puzzled.

    EDIT: Everything is hooked up fine, the signal is just too low. I have this fixed on my receiver.

    I still have to try internal signals, but I have the adapter modded to use the old lm1881 method. In a few days when I install the internal sync mod, I'll add switches to switch between lm1881, lmh1980, and internal sync.

    LM1881 + VGA2HDMI PRO gives a black bar. I can correct this by fine tuning the horizontal position on the VGA2HDMI PRO. I didn't get the black bar with the LMH1980, but the screen would flicker from time to time.
     
    Last edited: Aug 23, 2016
  7. N64 freak

    N64 freak Robust Member

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    Got some improvement hints for the vga mod.
    The idea i liked most was to combine both the LM1881 and the LMH1980 on one external adapter and use a select switch which one is active.
    With a second switch you could switch between internal sync signals and external ones. That would allow to have the internal, and both external sync signals with just one adapter.
    What do you guys think about the idea?

    BTW: If anyone is interested in testing the LMH1980 VGA mod in person i have one last LMH1980 cable i could offer. It's one off these 4 cables i just finished. So PM me if interested!
    [​IMG]
     
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  8. weinerschnitzel

    weinerschnitzel Spirited Member

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    I think it would also be pretty cool if the internal VGA sync amplifier was printed to fit around the AVIP and could connect to pins 7&8 with quick solder pads. Did you say you cut traces on these? SCART Blanking isn't used afaik, but are there any components connected to it?
     
  9. link83

    link83 Enthusiastic Member

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    Sorry to bump this thread, but i'm, curious if this VGA BIOS was ever finished?
    All the VGA BIOS I have found so far only support RGsB (Sync on Green) and I was really hoping to get pure RGB signals from an Xbox, especially since the Focus datasheet states:-
    So it would be great to get raw analog RGB signals, without any flicker filters or sync added to them.

    Also, my initial plan was to tap the HSYNC and VSYNC signals directly from the GPU, but after reading the Conexant datasheet I started wondering if we could perhaps configure the video encoders to output RGB+CSYNC?

    All the Xbox video encoders have four configurable DAC's, so shouldn't it be possible to configure them so that the fourth currently unused DAC is either Y(Luma) or SOG(Sync on Green)? From looking at the datasheet its clear you can have multiples of the same signal from different DAC's (e.g. You could have two Composite video outputs) so really all thats needed is to configure the DAC's to output RGB+Gs? (e.g. the fourth DAC outputs a second Green signal which is combined with CSYNC) That way we should be able to use use a standard Xbox SCART cable connected to an OSSC for all the possible video modes?

    I hope someones up to giving this a try! (Perhaps @MrNova or @bennydiamond?)
     
    Last edited: Jul 11, 2017
  10. nonosto

    nonosto Dauntless Member

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    need help for a vga cable, in ebay we can buy that:

    https://www.ebay.fr/itm/143347461008?ul_noapp=true

    this is vga cable but assume that scheme is a HDTV AV mode with vga outpout (2+3).

    [​IMG]

    I will use Frosty's BFM VGA BIOS Pack w/PBL Metoo on my debug kit (conexant encoder), on toshiba monitor tri sync from new net city cab. Must I take a VGA cable in VGA mode (1+3) or use HDTV mode?
     

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