Help with Sega I/O board on Naomi/Net city

[eScapes]

Recently got a Sega Net City, along with a Naomi GPU. It boots up and runs the game, but wont take any inputs, not even the "test" or service buttons. The I/O board is a Sega 837-13551

I've made sure everything is powered, and double checked that pins 1 and 3 are connected on the 60 pin harness. Any other ideas to trouble shoot?

Funny enough, the game will still boot even if the I/O board usb is disconnected. I won't get the "Jamma I/O board missing" error screen. not sure what that means.

any help appreciated

 

[meybarra]

For what it's worth, here's a photo of my working Sega IO board in my Naomi Universal. Same 837-1551 model:

 

[eScapes]

Thanks. turned out it was an issue with usb port on the naomi. had to dremel away the plastic cap on the back up port, and now it works like a dream

 

[LazerFlux]

Thanks. turned out it was an issue with usb port on the naomi. had to dremel away the plastic cap on the back up port, and now it works like a dream

sounds like the solder might have been loose on the filter board. For future reference, you might try reflowing it