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Feb 21, 2023
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I have a Sega JVS IO that is being detected by games. Coin counter and mechanism is connected and working (luckily an old £1 coin was in the machine!).

However if I load the BIOS menu up with the TEST button (on CAB), the SERVICE button doesn't work (in the game it adds a credit). If I try the buttons on the motherboard, its the same. If I unplug the JVS IO from the motherboard, the SERVICE button on the motherboard works again. I'm also finding the START button won't work either. Somehow the game has gone in a couple of times and it seems to register some presses, but it's rather random.

I did check without a game in and its the same. I mostly want to see the IO menus and test all the buttons.

I had to dismantle the machine to get it in my house, but I'm pretty confident I've hooked up everything bar anything screen related (as I don't have a tube or chassis).

Has anyone else had this problem? Am I missing something?
I would look for short circuits on the cables, but i guess something is wrong with the I/O.

Do you have another I/O PCB available?

Provide some Photos of the PCB (with plugged in cables) maybe we see something which causes the issue.
Sadly I only have another Sega JAMMA IO - that's working fine.

I have used a DMM to confirm the wiring looms have continuity.

I did some playing and found hitting the service button does eventually respond when I tried with my N2 (its incredibly laggy). It seems the N2 also behaves differently as games don't detect the IO. However I was able to get into the INPUT TEST on the BIOS finally where it sees it. The attached is with digital and analog bundles disconnected.

I'm fairly sure my IO is busted now. I've attached a photo of it all plugged in just in case (both LED are on).


Thanks for the advice though!