My SmallCab Supergun Deluxe v2.2 (french manual) has buttons on the board for coin1, coin2, service, and test. My game is already set to freeplay, so I'm not sure if the coin buttons work or not, but the test button doesn't seem to. It also has screw terminals for the button which do not work. I was prodding around with my multimeter and following traces when I found that a diode seems to be blocking the signal. Now normally I would expect a diode in there to prevent ghosting, but this is an arcade board with a pin for each input, not sure why you would need one. I don't know why else it would be needed (but my knowledge is pretty basic).
When I press the button I am not able to make a connection with my multimeter to pin 15. But I can connect pin 15 to the cathode end of the diode, which points towards the jamma pin. I tried looking up older models, and they seem to have the diode oriented in the other direction, and this model has them all oriented like mine.
I also found this diagram of an upcoming revision, I'm not sure if it's of any use:
You can see in the top right that the diode is pointing towards the button not the jamma pin. I'm very confused by this, is this a mistake in the design and I'm the first person to mention it??? Or do I have it completely wrong and I'm missing something?
When I press the button I am not able to make a connection with my multimeter to pin 15. But I can connect pin 15 to the cathode end of the diode, which points towards the jamma pin. I tried looking up older models, and they seem to have the diode oriented in the other direction, and this model has them all oriented like mine.
I also found this diagram of an upcoming revision, I'm not sure if it's of any use:
You can see in the top right that the diode is pointing towards the button not the jamma pin. I'm very confused by this, is this a mistake in the design and I'm the first person to mention it??? Or do I have it completely wrong and I'm missing something?
