Naomi 31khz works but Dreamcast 31khz doesn't - NNC VGA question

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    • Naomi 31khz works but Dreamcast 31khz doesn't - NNC VGA question

      I just picked up one of the New Net City's from XeD's group buy and had a question about these monitors.

      I've read that a Dreamcast with a VGA box should work at 31khz. The dreamcast turns on, I hear audio coming through the speakers on the cab but the monitor just displays No Signal. A Naomi board running 31khz works just fine, and the monitor also works in 15khz when the Naomi is set to 15. I've confirmed my Dreamcast VGA signal works in my Blast City and a HDTV.

      The only thing I can think of is that this specific chassis is incorrectly recognizing the Dreamcast VGA signal as 720x480 and therefore not accepting it.
    • I too picked up an NNC from XeD's group buy. Never tried hooking up a DC at 31khz before however.
      Another thing to check is to see if your VGA cable connection at the chassis is connected to the low impedence connection (VGA) and not the high impedence connection (15khz). If it is connected at the high impedence connection, I would expect that it does not work. But honestly don't know the chassis well enough to be sure either way.
      Arcade Multi Systems:
      • Sega: ST-V, Naomi w/Net Dimm, Naomi w/CF Boot (DIY and OG versions), Taito: G Net, Taito F3, Taito Type X², Capcom CPS2, Capcom CPS3, Neo Geo MVS 4-Slot
      Favorite Arcade Genres (in order):
      • Fighting games, Shmups, Light-gun, Puzzlers, Driving
    • acblunden2 wrote:

      Another thing to check is to see if your VGA cable connection at the chassis is connected to the low impedence connection (VGA) and not the high impedence connection (15khz). If it is connected at the high impedence connection
      I'll look again tonight but I swear I only saw one VGA connection on the chassis I have. That still wouldn't add up though, as XeD was flipping the Naomi from 31 to 15 on the Naomi and we didn't have to swap anything on the monitor hookups, the monitor displayed both the Naomi 15k & 31k signal fine. I'll do some more testing... a Pi should also work at 640x480 I assume.

      The post was edited 1 time, last by Zerrminator ().

    • Maybe you are right. See if you have a laptop with external VGA connection and output at 720x480 as well. If that doesn't work, then switch down to 640x480. If that works, then you confirmed the monitor can't do DC VGA, which kind of sucks. But I think there are only two DC games that are VGA compatible that are not on the NAOMI: Soul Calibur and Sturmwind.
      Arcade Multi Systems:
      • Sega: ST-V, Naomi w/Net Dimm, Naomi w/CF Boot (DIY and OG versions), Taito: G Net, Taito F3, Taito Type X², Capcom CPS2, Capcom CPS3, Neo Geo MVS 4-Slot
      Favorite Arcade Genres (in order):
      • Fighting games, Shmups, Light-gun, Puzzlers, Driving
    • MetalliC wrote:

      what kind of "VGA box" was used ? it is known when simplified cheaper adapters may not work with some display models.
      cause: sync lines voltage level.
      Ahh, yes. The Sanwa PFX chassis that might be in your NNC is known to have issues with sync too.
      Arcade Multi Systems:
      • Sega: ST-V, Naomi w/Net Dimm, Naomi w/CF Boot (DIY and OG versions), Taito: G Net, Taito F3, Taito Type X², Capcom CPS2, Capcom CPS3, Neo Geo MVS 4-Slot
      Favorite Arcade Genres (in order):
      • Fighting games, Shmups, Light-gun, Puzzlers, Driving
    • MetalliC wrote:

      what kind of "VGA box" was used ? it is known when simplified cheaper adapters may not work with some display models.
      cause: sync lines voltage level.
      I'm using my knock off Dreamcast VGA box that I bought from Hong Kong around the time when Dreamcast launched. It looks similar to the OEM Sega one but clearly cheap 3rd party, the audio is terrible.
      photobucket.com/gallery/user/c…2EwOTZiZDJlLmpwZw==/?ref=

      Like I said it does work on my Blast City and all of the LCD's/HDTV's I've ever tried it on. Is there anyway to "add an in-line" sync cleaner to improve compatibility? Or converter etc?

      That said, I have been wanting to invest in a BeharBros VGX box for a long time... maybe it's time to just get a good one.
    • Let me dig up my VGA cable and box to see if it works on my Sanwa PFX-based NNC before you drop the dough on Behar Bros. Won’t be till the end of the week when I get home though.

      Can u confirm you got the Sanwa PFX chaasis as well?
      Arcade Multi Systems:
      • Sega: ST-V, Naomi w/Net Dimm, Naomi w/CF Boot (DIY and OG versions), Taito: G Net, Taito F3, Taito Type X², Capcom CPS2, Capcom CPS3, Neo Geo MVS 4-Slot
      Favorite Arcade Genres (in order):
      • Fighting games, Shmups, Light-gun, Puzzlers, Driving
    • Zerrminator wrote:

      Where do I look to confirm the chassis model?
      A quick way to determine (within reason) is that the chassis is tan/brown, not green.

      That'll differentiate between Toshiba/Sanwa, but not if somehow you ended up with Wei-ya, or some other chassis (pretty unlikely).
      On the hunt for: Dinoking, Mushiking, Love & Berry, Egret 29, Grand Am Q25, Capcom New Concept 2, and Naomi guncabs.
    • archimage wrote:

      my nnc takes dreamcast vga with the beharbros without any problem.

      I have a Toshiba PD1843 chassis
      The Toro, right? Do you set it to RGBS or RGBHV? Can you switch it from one to the other and see if you have the same results?
      Arcade Multi Systems:
      • Sega: ST-V, Naomi w/Net Dimm, Naomi w/CF Boot (DIY and OG versions), Taito: G Net, Taito F3, Taito Type X², Capcom CPS2, Capcom CPS3, Neo Geo MVS 4-Slot
      Favorite Arcade Genres (in order):
      • Fighting games, Shmups, Light-gun, Puzzlers, Driving
    • rewrite wrote:

      Zerrminator wrote:

      Where do I look to confirm the chassis model?
      A quick way to determine (within reason) is that the chassis is tan/brown, not green.
      That'll differentiate between Toshiba/Sanwa, but not if somehow you ended up with Wei-ya, or some other chassis (pretty unlikely).
      The chassis is not green. It's more of a tan color for sure. I'll take some pics tonight and post.
    • So tonight I tested my other cheap $10 Dreamcast VGA cable and it actually works. But the main issue I'm seeing is every now and then the picture will just cut out momentarily in some games, then the monitor brings the picture back. The picture is horizontally & vertically stable, then all of a sudden it will go black for a split second, then come back. Some games seemed perfectly fine with no issues, others like Sonic Adventure would cut out every 10-30 seconds. This is exactly what my Blast CIty was doing with my VGA box and cable as well, both 3rd party cheap items. Would a better VGA Box help fix this? Is this an issue with poor sync going into the chassis? Is there some kind of sync cleaner/booster that can be added in-line to help?

      It looks like I have the KW0606 like XeD said.

      Photos
      imgur.com/gallery/m7GjHNR
    • Depends on what sync is coming out of your VGA box/cable. Probably best if you just swoop up a Toro. That gives you the ability to output VGA as RGBs or RGBHV. But you would be blazing a trail here that others in the group guy shall follow. I don't think you're losing much here if it doesn't work out; you said you were investing in a better VGA box anyway.
      Arcade Multi Systems:
      • Sega: ST-V, Naomi w/Net Dimm, Naomi w/CF Boot (DIY and OG versions), Taito: G Net, Taito F3, Taito Type X², Capcom CPS2, Capcom CPS3, Neo Geo MVS 4-Slot
      Favorite Arcade Genres (in order):
      • Fighting games, Shmups, Light-gun, Puzzlers, Driving