Naomi 2 - No VGA Signal in 31.5kHz

OldFoo · Post by **OldFoo** » Tue Aug 16, 2011 10:54 pm

Hello everyone.

My name is Paolo and I write from Italy!

(Sorry for my English)

I recently purchased a Naomi 2 but I have the same problem of an old post reported on this forum (http://www.sega-naomi.com/forum/viewtop ... ht=bizarre)

When I connecting the Naomi to a VGA monitor, i can not see anything (the dipswitch 1 is correct to off. In 15kHz i don't have problem in monitor CRT mounted in CAB).

The only game that works is Ikaruga (only when the game start, i can't see a naomi boot screen and test mode)...

I read that "HORIZONTAL SCANNING FREQUENCY: 15.85kHz / 31.69kHz" while my monitor accepts only 31.5 khz.

I read another post (http://www.sega-naomi.com/forum/viewtop ... ght=#15642) about an internal Jumper...

Can anyone tell me if i can solve the problem?

Thanks to everyone who responds!

OldFoo · Post by **OldFoo** » Sun Aug 21, 2011 9:20 pm

Hello everyone!

No one has ever found the problem mentioned above?

Thanks to whoever responds.

OldFoo · Post by **OldFoo** » Mon Aug 22, 2011 4:38 am

It sounds like your monitor just doesn't like the Naomi, try using a different monitor.

I think the jumpers mentioned are only present on the 2001 shorter main board version of the Naomi, but I don't have a functional one of those to play with.

OldFoo · Post by **OldFoo** » Mon Aug 22, 2011 6:47 am

Hello!

Thanks for the reply!

But why Ikaruga works?

It Use a resolution or scan rate different?

I tried to use an adapter to convert the VGA signal (PCtoTV) but behaves in the same way as the LCD TV. Only Ikaruga works.

Thanks!

OldFoo · Post by **OldFoo** » Tue Aug 23, 2011 3:14 am

Ikaruga outputs a slightly different sync rate than most other games according to that thread you linked. I don't have that game currently, but I know other games like Death Crimson do have control of the sync rate the Naomi outputs.

PC to TV adapters typically have even more trouble dealing with sync rates than regular PC monitors.

OldFoo · Post by **OldFoo** » Tue Aug 23, 2011 7:47 am

Hello.

"... Death Crimson do have control of the sync rate the outputs Naomi ..."

Very interesting!

I will try soon as I can.

But I think the problem is due to the fact that Naomi not has a VGA output at 31.5khz but at 31.69KHz.

Some monitors do not have this tolerance ...

Using the PC-TV to turn on the monitor horizontal vertical games.

OldFoo · Post by **OldFoo** » Tue Aug 23, 2011 6:11 pm

I meant that Death Crimson changes the sync rate on its own, not that you had manual control of the sync rate when using it. Sorry for the confusion.

In 15kHz mode of Death Crimson the startup screen is running at a different sync rate than what the game uses, which confuses one of the LCD monitors I was using it on (ended up with 'Insert Coins' at the top of the screen occasionally).

OldFoo · Post by **OldFoo** » Tue Aug 23, 2011 11:35 pm

Ah, ok!

Thanks!