Coin switches are not triggering for JVS I/O board for Naomi Universal cab

[avramce]

Hi all,

I had not touched the inner wiring to the IO board nor my coin door switches, yet, my Naomi cab stopped detecting quarters when inserting coins to both the P1 and P2 slots. This had been working previously, but I noticed that when I was using the cab with a Jammaifier, it would not accept coins for both players. I switched the cab back to the Naomi 2 board that the cab came with, and I could not get any coins to register in any games or the IO test menu.

I had confirmed the coin door switches are functional with a multimeter, confirmed the system would accept credits with the service buttons, and even swapped in a new JVS IO board to no avail. Any suggestions on what to dig into next? I'd hate to have to leave the cabinet on free play, but it sounds like that is the only option to unblock myself in the meantime.

 

[nnap]

there is a connector that connects the coin mech to the credit board. Check that to see if the signal from the coin mech is registered.

 

[avramce]

there is a connector that connects the coin mech to the credit board. Check that to see if the signal from the coin mech is registered.

Wait, is there another board in-between the mech and the IO board behind the control panel? I thought the mechs just wired directly to the pin 49 and GND on the digital side of the IO board:
https://wiki.arcadeotaku.com/w/JVS#Sega_837-13551

Either way, any suggestions are greatly appreciated, this minor detail is killing me

 

[nnap]

it depends on the coin mech. If it is an electronic one, there will be a credit board between the coin mech and the I/O. You should see it to the right of the I/O if you remove the monitor bezel. I had one of these fail on a naomi universal. Replacing it fixed it. On my cab I installed a 100Y mechanical coin mech. That one is directly connected to the JVS I/O.