Naomi + Vewlix F = Black screen

[jugu]

Hi folks,
I'm having trouble with a recently acquired Naomi motherboard and a Vewlix F. When I connect the Naomi to the VGA cable of the Vewlix, all I see is a black screen. I'm hoping someone has some suggestion as to how to resolve my problem. I've verified the following:
* Dip switches set correctly to 31khz
* Voltage: 12v, 3.3, 5v, have all been adjusted and are set accordingly
* Power: The Naomi motherboard powers up, fan and led lights are on

I've tried the following:
Naomi -- VGA --> Vewlix = Black Screen
Naomi -- VGA --> XRGB-3 -- VGA --> Vewlix = Black Screen

Now I don't have a Naomi game to try it with at the moment, just the motherboard. However, I have a Naomi2 motherboard that I can boot without a game and get to the service menu successfully on the same Vewlix.

Is the black screen expected when booting with out a game? Anything else I can try?

Thank you!

jugu

[Jockel]

Did you try to use the Naomi on a normal VGA monitor, to rule out a faulty motherboard?

[arcade-stg]

Are you powering the naomi from the JVS Power Supply of the Vewlix?
The JVS Power Supply of the vewlix requires exactly 100v of input, otherwise the naomi is not going to correctly power up.

[jugu]

Yes, I did try the Naomi motherboard with another VGA monitor, and it still displayed the black screen.

I am powering the Naomi from the JVS power supply in the Vewlix. I'm using a stepdown transformer, https://acupwr.com/collections/japan-to ... -countries, to output 100v. I'd read about the Wei Ya power supplies being finicky.

Thank you for the responses.

[Unseen]

Is the black screen expected when booting with out a game?

No, the Naomi should at least show its logo and complain that there is no game inserted or that it is invalid (I don't remember which). I think it takes quite a long time (a minute?) until you see something other than a black screen though.

[jugu]

Thank you for your reply. I have a Naomi 2 system that does boot up and display the cartridge error on the same machine. I've concluded that it is a defective Naomi motherboard and sent it back. Hopefully the next one works in my setup.

jugu