Sega-Naomi

I bought an untested/as-is Naomi 1 a while ago. Just built an ATX->Naomi power harness and I'm not getting any video. Checked my wiring twice with a meter and looks fine. The Naomi fan is running and I can see red & green LEDs on the PCB under the top vent.



I haven't connected anything for I/O or audio yet, just the base Naomi with both 6 & 8 pin power plugs and running the video connector out to my monitor. I've tried the dipswitches at 1 ON, 2-4 OFF and 1-4 OFF but just a black screen.



Am I missing something or is it probably DOA? I should at least be getting video from this basic setup, right?

You should at least get the logo and an error message or something. When you're sure you jumpered the right frequency (15 or 31K) and your wiring is correct then it's probably broken. I've had a case like this and i just replaced the filterboard and my problem was solved. Filterboards can be found on here for around 10 euro's. Worth a try i think.

make sure the cpu fan is running



is there any sound at all ?



if there is startup sound, and no video, could have bad sync trace on filter board ( this is seen if you remove filter board and check back side ).



no sound + no video + spinny fan = most likely bad.

You need to hook up the sound. If you have no sound then you probably have a dead system.



Next to the battery on the board is a supercap for keeping the backup memory. Look at the circuit board around the cap for oily looking gunk on the board. That gunk likes to attract dust so it may look dirty/smudgy.



That gunk is electrolyte and will eat traces on the board.



If it's there then that may be what happened to the board. There's an 8 pin EEPROM next to the cap and one or more traces under the socket have probably been damaged.



If you have sound then either you have a bad filter board or a bad RAMDAC chip on the NAOMI board.