Tighe
Well-known member
Negative Speaker wire has to be connected to ground for sound to work?! Why??
So this weekend I was making a JAMMA adapter for my Japanese Taito Space Invaders Part II cocktail cabinet. When I got this cabinet it had a Big Kong board in it (converted bootleg Galaxian).
The board in the cabinet plugs into the existing Space Invaders harness (two edge connectors), and has an additional connector for the player 1 and 2 up, down, and jump buttons.
The weird thing was I was getting rolling interference on the monitor with the audio (both the Big Kong board and the JAMMA 60-in-1 connected). I found a wire connected the hinge on the table to the negative terminal on the speaker. When I disconnected this wire the interference went away and it worked great with the 60-in-1 board, but I had now audio in Bg Kong.
I used an alligator clip and connected the negative terminal to the shielding on the power supply. This restored the audio in Big Kong, but the audio on the JAMMA 60-in-1 is quieter when connected.
Additionally, the player 2 side of the controls are weird and I think have a different ground, as they work fine on the Big Kong, but I cannot get them to work on the 60-in-1.
Anyone worked on this kind of cabinet before and can help me out?
So this weekend I was making a JAMMA adapter for my Japanese Taito Space Invaders Part II cocktail cabinet. When I got this cabinet it had a Big Kong board in it (converted bootleg Galaxian).
The board in the cabinet plugs into the existing Space Invaders harness (two edge connectors), and has an additional connector for the player 1 and 2 up, down, and jump buttons.
The weird thing was I was getting rolling interference on the monitor with the audio (both the Big Kong board and the JAMMA 60-in-1 connected). I found a wire connected the hinge on the table to the negative terminal on the speaker. When I disconnected this wire the interference went away and it worked great with the 60-in-1 board, but I had now audio in Bg Kong.
I used an alligator clip and connected the negative terminal to the shielding on the power supply. This restored the audio in Big Kong, but the audio on the JAMMA 60-in-1 is quieter when connected.
Additionally, the player 2 side of the controls are weird and I think have a different ground, as they work fine on the Big Kong, but I cannot get them to work on the 60-in-1.
Anyone worked on this kind of cabinet before and can help me out?

