My Adventures of Rocky and Bullwinkle and Friends has a strange sound problem. When the data cable which connects the mpu to the sound board is plugged in, the sound is aweful. It's jittery and goes on and off rapidly like a machine gun. Also, it won't change to the next sound - it stays stuck on one effect. When I unplug the cable, the sound is clear, but of course, will continue to play the same sound and not move to the next. I've tried replacing the cable with one that I know works. I've tested the pins and surrounding chips with my logic probe and compared them to another data east game and they look fine. I've re-flowed the solder on the pins. It was working fine this morning. I took the board off to check something else and when I plugged it all back in, this problem showed up. I've confirmed that the data cables are plugged in correctly - not upside down or moved over. Any suggestions?

Still stumped by this.

It turns out I did have the cable in backward. Dumb mistake. Thanks for the reply.