Needing help: 31kHz to 15Khz Jamma adapter

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    • Needing help: 31kHz to 15Khz Jamma adapter

      Actually I am not sure if this is the right place in the forum for this question:
      I want to use my TypeX2 or XBOX360 on my Astro City cabinet, therefore I need a converter for 31kHz to 15kHz.
      The problem I encounter is that these chinese downscalers:

      output with 5 pins to rgb. Since I want to lead the signal through my Capcom i/o (for the joystick signals via USB from Taito TypeX2) I need an adapter from this VGA2CGA (5 pins) to a 15pin RGB pinout to connect to my Capcom i/o. If I use this VGA 15 Pinout, I only get 31kHz to Capcom I/o,



      so I need some idea how to do this adapter where CSync is HSync and VSync combined. Or am I wrong ?

      So mainly: I need the converted signal from this VGA2CGA to be connected to my Capcom i/o so that I have 15kHz input on Capcom i/o. Any thoughts about this ?

      Thx
      Jan
    • I don't know shit about the Chinese scalers, but if you can find one... You want the mighty UVC!


      Hasuki-san wrote:

      so I need some idea how to do this adapter where CSync is HSync and VSync combined. Or am I wrong ?
      Again never used one but that information should be WRONG.
      IF the device it outputting 15khz it is also outputting Csync on pin13.
      Only VGA output would use separate H (pin13) and V (pin14) syncs, this is the spec/standard.

      Some devices like the PVM20L5 monitor for example have no problems displaying VGA, however they require Csync.
      So for a device like this, yes you need to composit the H and V syncs of a VGA output.
      For that I recommend the Extron RGB 580xi...

      Darksoft: CPS3, ST-V, CPS2, F3, MVS
      RGB: RECO v2, HAS v3


      [genesis] [segacd] [saturn] [dreamcast_ss] [nes-101] [snes] [n64] [gamecube] [pce] [pcecd] [psx]

      The post was edited 3 times, last by jassin000 ().

      Post by brad808 ().

      This post was deleted by the author themselves ().
    • it's not good form to simply join the sync lines like that. it depends on the specific hardware design and where in the circuit you're joining them but it could potentially cause damage to the sync output IC or cause a short.

      the safe/right way to do it is to feed them through an OR gate. Or, at minimum, pass them through some resistors before joining them.

      -------------

      As Jassin suggested the UVC is the best tool for the job.

      I will say that a lot of Monitors will run with just H-Sync on the Sync Pin, and a lot of 31KHz arcade boards can be set to output C-sync too... so there may not be any issues with the sync at all.
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    • twistedsymphony wrote:

      so there may not be any issues with the sync at all.
      Other than stripping...

      Some PCBs need this others don't, it really comes down to the combo of monitor and source.
      If you get a rolling image, that won't stabilize its a pretty sure sign of strippers being needed.

      Running thru a converter I wouldn't expect this, but if you experience it remember strippers baby!

      twistedsymphony wrote:

      it's not good form to simply join the sync lines like that.
      OMG this x1000!
      Yes often times this will produce a image that will "display" but its stressing the shit out of your monitor (you do care about that MS8/9 right).

      Use a professional device like the Extron 580 if you need to composite H and V syncs.
      Or take the time to research like Twisted said, and build the appropriate (gated) solution.
      Darksoft: CPS3, ST-V, CPS2, F3, MVS
      RGB: RECO v2, HAS v3


      [genesis] [segacd] [saturn] [dreamcast_ss] [nes-101] [snes] [n64] [gamecube] [pce] [pcecd] [psx]

      The post was edited 4 times, last by jassin000 ().

    • okay, thanks for your replies. So the extron seems to be the perfect solution. Where do I get that besides eBay ?
      For me it seems that I am the only one trying to force 31kHz to 15kHz and nobody trying to play Cave shmups on XBOX360 on Astro City. Maybe I should just buy a Blast City and everything will be okay :) But I like my Astro so much. Anyway thanks for your help !
    • jassin000 wrote:

      OMG this x1000!
      Yes often times this will produce a image that will "display" but its stressing the shit out of your monitor (you do care about that MS8/9 right).
      No it won't. Not at all. Like twisted say is bad form and I agree some situation it isn't good. in this one you are absolutely safe to only hook up those like that. I can write you better later but for now just some quick data for sync processor toshiba.semicon-storage.com/in…16770&prodName=TC74HC86AP

      no gate is conversion of your signal into anything dangerous here. would be protection should you not know what you are doing and hook up somehting dumb.
      see signal you are way underspec and exactly what it want:


      if you don't understand past that then you'll have to explain to me why it will stress because otherwise just a guess for me.