Sega Naomi universal monitor issue

[Rob_bob_2k6]

I had a Naomi universal delivered today, which was working before being shipped.

Now when I turn it on I get horizontal lines which then fade and the screen stays blank.

Is anyone able to offer an troubleshooting help please?

I’ve tried a Dreamcast into the vga port in case it was the Naomi motherboard and that does the same thing.

Thanks a lot for any help

 

[gunblade]

reseat the neck card and all connectors to the chassis- you will need to take the plastic cover off the back of the cab

locate screen volts adjustment pot on flyback and turn anti clockwise a small amount

 

[devtty0]

On my naomi, it gets a blank screen when I first turn it on, if I leave it on for a short while and then power cycle it, I see a screen which quickly fades to black.

If I then leave it on a bit longer, if I power cycle again, the picture comes up and stays on.

Dont know whats happening, but it at least works. Caps maybe?

There is also a fizzing sound from the annode, which sounds like its fizzing out when it fades to back, and stays when the picture stays.

 

[Fantazia2]

I would say check the seating of all the cables related to the monitor, including the remote board that is in the control panel area, but you will need to remove the screen surround to access that I think from memory.

Something could have rattled loose during transport.

Also with the rear plastic surround off when the screen goes blank have a look to see if its losing neck glow.

 

[Rob_bob_2k6]

I’ve done than and now get the horizontal white lines on a grey screen but it doesn’t fade it stays on the screen.

 

[Fantazia2]

As mentioned by DevTTY the Naomi MB's sometimes take a while to boot, if you leave it for a while do you hear anything coming our of the speakers, pretty sure they have a boot up sound.

If you could stick a picture up of what your seeing that might help.

 

[Rob_bob_2k6]

The game is playing out of the speakers, so is def in game.

Neck doesn't ever seem to glow all that bright.

Im taking the surround off now to check connections there.

I had already reseated the cables on the chassis.

Thanks

 

[Rob_bob_2k6]

Taken the control panel off, nothing seemed lose. Seated a few bits and no difference.

 

[jinq-sea]

Is the ground wire connected on the neck card?

 

[Rob_bob_2k6]

I can’t see anything lose that looks like it

 

[jinq-sea]

Upload some pics with the back off - might be sensible.

 

[Rob_bob_2k6]

Heres on of the neck card whilst running:

 

[jinq-sea]

Chassis too would help if you can

jinq-sea2021-09-09 15:37:35

 

[Sbdesign]

did you turn the gain up or down?
it looks like you turned it up

 

[Rob_bob_2k6]

 

[Rob_bob_2k6]

 

[Velyks]

You can see the retrace lines, I think your screen volts are up way too high. To lower them it should be the knob/dial labeled "SCREEN" on the back of the flyback.

 

[Rob_bob_2k6]

Would that be anti clockwise?

 

[jinq-sea]

It really does look like the screen volts are turned right up yes! Screen pot on the flyback - turn it a little anticlockwise. Gunblade (who knows a sh*tload about monitors) suggested this above. Try it :thumb:

 

[Rob_bob_2k6]

It’s already as far as it will go anti clockwise