I recently purchased a Naomi 2 setup to add into my Sega New Astro City, which is currently running MAME using a JPAC ..
Because of the PC, the onboard power supply is disabled, but I do use the JAMMA harness with the JPAC to feed the MS9-29A 15khz video and all joysticks/buttons connect via JAMMA.
Here's how I connected the Naomi 2:
- Naomi (SUN) PSU with 2 power connectors to main board
- USB cable from main board to Sega IO rev B
- VGA cable from main board to Sega IO
- Sega IO gets its power from the PSU using little 6 pin connector
- Sega IO plugged into JAMMA harness in NAC
- RCA plugs go to small external amp driving speakers
- Monitor + Marquee lights + AMP + PSU all connect to power bar inside NAC
- jumper set to 15khz
The issue I'm having is no video / no audio. I've confirmed using a multimeter 5.1V, 3.4V and 11.95V. I tested all test points on Naomi 2 and voltage set correctly. The 2 lights on main board are on, and 3 fans are spinning. All I get is black screen.
I can hear a relay click on the IO board when power is on/off.
Am I missing something? Does the JAMMA harness need power from the NAC PSU, or getting power from same PSU as Naomi 2 good enough? What about sync? Does the SEGA IO rev B provide the correct sync for an MS9-29A?
As a last resort, I flipped the dipp switch to 31khz, and tried plugging to a PC VGA port as well as my HDTV.. both said no signal.
The last thing I'd like to add.. the board came to me with the USB port 1/2 ripped off! (damaged in transit -- thanks USPS!) I desoldered/soldered it back on using my rework station and confirmed all connections are good. Could it be that something else broke inside causing black video/no sync?
Or do I need to do something to the video output from a Sega IO rev B before feeding it into an MS9-29A?