NAOMI Dark / Dull video output

[codecrank]

Got two naomis, and two blast cities. all combinations results in a dim / dull screen. ( like compared to a my hypserspin pc )

5v is good
went through all the possible chassis & remote board adjustments...

is there some known component that commonly causes this in a naomi ?

 

[nem]

What connection are you using?

Which monitor? 2930 or 2931? 2931 has the OSD.

 

[Zebra]

I get a dull image from certain systems on my Tri-sync CRT monitor's if I don't change the .75ohm / 1kohm switch on the remote board. Oddly, I always have to turn the brightness way down for regular PC output even when the monitor is set for consumer rgb.

My PS2 has the opposite problem - it's always dull on my arcade monitors so I have to use an RGB booster. I got mine from Ultimarc. It's the product they sell to use use consumer consoles on old CGA arcade monitors to avoid a dull image. It's probably cheaper than buying the official Sega rgb amplifier anyway:

https://www.ebay.com/itm/Tested-SEG...JVS-PCB-Retro-Arcade-Game-Japan-/313061546881

This is the Ultimarc one I use:

https://www.ebay.com/itm/Video-Ampl...691512?hash=item5b42db49f8:g:b2gAAOSwuhhXVapM

 

[CoolFox]

Got two naomis, and two blast cities. all combinations results in a dim / dull screen. ( like compared to a my hypserspin pc )

5v is good
went through all the possible chassis & remote board adjustments...

is there some known component that commonly causes this in a naomi ?

See if the ground blew on the filter board's RGB. Also, check the RGB dac on the motherboard to see if it's getting hot.

 

[codecrank]

Thank you all for the response, much appreciated

What connection are you using?

Which monitor? 2930 or 2931? 2931 has the OSD.

2931 ( auto ) , tried both direct db15/vga input, and RGBS through the sega jamma/jva io

I get a dull image from certain systems on my Tri-sync CRT monitor's if I don't change the .75ohm / 1kohm switch on the remote board. Oddly, I always have to turn the brightness way down for regular PC output even when the monitor is set for consumer rgb.

My PS2 has the opposite problem - it's always dull on my arcade monitors so I have to use an RGB booster. I got mine from Ultimarc. It's the product they sell to use use consumer consoles on old CGA arcade monitors to avoid a dull image. It's probably cheaper than buying the official Sega rgb amplifier anyway:

https://www.ebay.com/itm/Tested-SEG...JVS-PCB-Retro-Arcade-Game-Japan-/313061546881

This is the Ultimarc one I use:

https://www.ebay.com/itm/Video-Ampl...691512?hash=item5b42db49f8:g:b2gAAOSwuhhXVapM

yeah I'm familiar with remote board dip switch on the 2930, but this monitor it's an auto.
wow, the VS kit twin out pcb is getting as expensive as what I paid for a whole vs kit years ago.
I was wondering about an rgb booster , something that brings it up 0-0.7v p2p, but this is more of something that brings it to a 0-5v p2p . not sure if it would help

Got two naomis, and two blast cities. all combinations results in a dim / dull screen. ( like compared to a my hypserspin pc )

5v is good
went through all the possible chassis & remote board adjustments...

is there some known component that commonly causes this in a naomi ?

See if the ground blew on the filter board's RGB. Also, check the RGB dac on the motherboard to see if it's getting hot.

ahhh dude you lose me as usual lol
> ground blew
like one of the emi filters ? how do I check that ?
> RGB dac
I know it's small, but, any code or number to help ID the dac ?

 

[CoolFox]

Thank you all for the response, much appreciated

What connection are you using?

Which monitor? 2930 or 2931? 2931 has the OSD.

2931 ( auto ) , tried both direct db15/vga input, and RGBS through the sega jamma/jva io

I get a dull image from certain systems on my Tri-sync CRT monitor's if I don't change the .75ohm / 1kohm switch on the remote board. Oddly, I always have to turn the brightness way down for regular PC output even when the monitor is set for consumer rgb.

My PS2 has the opposite problem - it's always dull on my arcade monitors so I have to use an RGB booster. I got mine from Ultimarc. It's the product they sell to use use consumer consoles on old CGA arcade monitors to avoid a dull image. It's probably cheaper than buying the official Sega rgb amplifier anyway:

https://www.ebay.com/itm/Tested-SEG...JVS-PCB-Retro-Arcade-Game-Japan-/313061546881

This is the Ultimarc one I use:

https://www.ebay.com/itm/Video-Ampl...691512?hash=item5b42db49f8:g:b2gAAOSwuhhXVapM

yeah I'm familiar with remote board dip switch on the 2930, but this monitor it's an auto.
wow, the VS kit twin out pcb is getting as expensive as what I paid for a whole vs kit years ago.
I was wondering about an rgb booster , something that brings it up 0-0.7v p2p, nice to know about the ultimarc one

Got two naomis, and two blast cities. all combinations results in a dim / dull screen. ( like compared to a my hypserspin pc )

5v is good
went through all the possible chassis & remote board adjustments...

is there some known component that commonly causes this in a naomi ?

See if the ground blew on the filter board's RGB. Also, check the RGB dac on the motherboard to see if it's getting hot.

ahhh dude you lose me as usual lol > ground blew
like one of the emi filters ? how do I check that ?
> RGB dac
I know it's small, but, any code or number to help ID the dac ?

Haha, basically look at all of the traces that come off the VGA port...see if any are blown. As for the DAC I think it's 315-6145.

 

[nem]

I want to say 2931 has separate settings for 31khz. Does the Naomi look dim in 15khz as well?

I just find it weird that both Naomis would be faulty. Certainly possible.

 

[nnap]

If you disconnect the video signal for 15khz under the bezel, you will get a slightly brighter picture.

So just remove the bezel, unplug the video signal connector and leave the power/degauss connected.
Then use the vga cable for video.

 

[Zebra]

Thank you all for the response, much appreciated

What connection are you using?

Which monitor? 2930 or 2931? 2931 has the OSD.

2931 ( auto ) , tried both direct db15/vga input, and RGBS through the sega jamma/jva io

I get a dull image from certain systems on my Tri-sync CRT monitor's if I don't change the .75ohm / 1kohm switch on the remote board. Oddly, I always have to turn the brightness way down for regular PC output even when the monitor is set for consumer rgb.

My PS2 has the opposite problem - it's always dull on my arcade monitors so I have to use an RGB booster. I got mine from Ultimarc. It's the product they sell to use use consumer consoles on old CGA arcade monitors to avoid a dull image. It's probably cheaper than buying the official Sega rgb amplifier anyway:

https://www.ebay.com/itm/Tested-SEG...JVS-PCB-Retro-Arcade-Game-Japan-/313061546881

This is the Ultimarc one I use:

https://www.ebay.com/itm/Video-Ampl...691512?hash=item5b42db49f8:g:b2gAAOSwuhhXVapM

yeah I'm familiar with remote board dip switch on the 2930, but this monitor it's an auto.wow, the VS kit twin out pcb is getting as expensive as what I paid for a whole vs kit years ago.
I was wondering about an rgb booster , something that brings it up 0-0.7v p2p, nice to know about the ultimarc one

Got two naomis, and two blast cities. all combinations results in a dim / dull screen. ( like compared to a my hypserspin pc )

5v is good
went through all the possible chassis & remote board adjustments...

is there some known component that commonly causes this in a naomi ?

See if the ground blew on the filter board's RGB. Also, check the RGB dac on the motherboard to see if it's getting hot.

ahhh dude you lose me as usual lol > ground blewlike one of the emi filters ? how do I check that ?
> RGB dac
I know it's small, but, any code or number to help ID the dac ?

Haha, basically look at all of the traces that come off the VGA port...see if any are blown. As for the DAC I think it's 315-6145.

The RGB booster gives you a brighter image. As the problem is a dull image, it will probably solve it.

Arcade monitors often look dull with consumer rgb sources. I'm not super familiar with the Naomi hardware but if it behaves like the the consumer Dreamcast console then I would expect a dull image on some of my arcade monitors without the rgb amp.

As an official Sega RGB amp exists for the Naomi hardware, I'm guessing the RGB Amp is necessary for some 15khz cab conversions.

 

[nem]

I haven't had any problems with a Naomi in a Blast.

 

[codecrank]

The RGB booster gives you a brighter image. As the problem is a dull image, it will probably solve it.

Arcade monitors often look dull with consumer rgb sources. I'm not super familiar with the Naomi hardware but if it behaves like the the consumer Dreamcast console then I would expect a dull image on some of my arcade monitors without the rgb amp.

As an official Sega RGB amp exists for the Naomi hardware, I'm guessing the RGB Amp is necessary for some 15khz cab conversions.

What I'm trying to say is that here is that:

That ultimarc rgb amp is designed to take a VGA signal from a videocard ( 0 - 0.7v ) and boost the voltage range to be used on a standard arcade CGA monitors ( 0 - 5v ). if all it does is use a simple multiplier, and my naomi isn't outpuing VGA at full range ( ie pure is well below 0.7v ) , then the CGA signal will have the same issue ( pure white is well below 5v ) . make sense ?

btw, there is no such thing as a Naomi RGB amp, that ebay seller needs to do some research... https://wiki.arcadeotaku.com/w/Sega_Blast_City_Vs_kit ( I wrote this years ago when I had the kit, which now belongs to @KaPH33n btw )

 

[Zebra]

The RGB booster gives you a brighter image. As the problem is a dull image, it will probably solve it.

Arcade monitors often look dull with consumer rgb sources. I'm not super familiar with the Naomi hardware but if it behaves like the the consumer Dreamcast console then I would expect a dull image on some of my arcade monitors without the rgb amp.

As an official Sega RGB amp exists for the Naomi hardware, I'm guessing the RGB Amp is necessary for some 15khz cab conversions.

What I'm trying to say is that here is that:
That ultimarc rgb amp is designed to take a VGA signal from a videocard ( 0 - 0.7v ) and boost the voltage range to be used on a standard arcade CGA monitors ( 0 - 5v ). if all it does is use a simple multiplier, and my naomi isn't outpuing VGA at full range ( ie pure is well below 0.7v ) , then the CGA signal will have the same issue ( pure white is well below 5v ) . make sense ?

btw, there is no such thing as a Naomi RGB amp, that ebay seller needs to do some research... https://wiki.arcadeotaku.com/w/Sega_Blast_City_Vs_kit ( I wrote this years ago when I had the kit, which now belongs to @KaPH33n btw )

There's no standard for rgb brightness / voltage. They come in a range depending on the source, cables, equipment age etc (and vary with changes in resolution). The amps just boost power from the R, G and B lines from whatever it is.

I've personally never had any brightness issues from pc GPUs on any of my arcade monitors. I've only experienced issues on certain consoles on certain monitors. My PS2 has no issues on my Billabs Tri-sync but looks dull on my Makvision Tri-sync even though My PC, Supergun, Neo Geo AES etc all work fine.

Anyway, I use an RGB amp to make my PS2 bright enough for light guns on my Makvision without having to max out the contrast pot.

I assume Sega made it's RGB amp as an external add-on because brightness issues are monitor specific (or it would just have been part of the Naomi hardware). I'd assume that amps may become necessary on some older cabs too, even if they weren't needed when the monitor was new.

BTW, do the JVS to Jamma convertors for the Naomi have a built in RGB amp?

 

[nem]

BTW, do the JVS to Jamma convertors for the Naomi have a built in RGB amp?

Yes, because video is piped through the jamma connector and the monitor will expect high impedance from it. The amp on the Sega 838-13683-93 (rev.B) is a BA7666FS.

 

[Heatermania]

Just got one of the Ultimarc video amps posted on this thread because my Sega Naomi has a dull video output on my 15khz monitor.

Problem is, I have absolutely no idea how to install it. Are there any pictorial/video tutorials?

trying to get the Naomi looking good on the monitor for my Capcom Big Blue.

 

[Zebra]

It's just a vga in with output on labelled screw terminals (R, G, B, H, V).

The only additional input is 5v for rgb sources that don't already output 5v on pin 9. They show a pic of where an external 5v would go on the Ultimarc site.

 

[tonyt76]

@codecrank did you ever resolve this issue? My Naomi 2 looks dull/dark on my tri-sync too but 15khz looks amazing?

 

[codecrank]

@codecrank did you ever resolve this issue? My Naomi 2 looks dull/dark on my tri-sync too but 15khz looks amazing?

oh you'll laugh, on cab #1 I just had to tune the video settings ( crank up brightness and contrast ) . not sure why the Naomi's output levels are so much lower than a pc, but it just it just is.. on cab #2, well that tube needs a rejuv ( recap din't help, can barely get an acceptable level with 15k boards )