Quoted from drummermike:My torpedo lights are on and I can't fire. The button works and then it doesn't. Should not be a mechanical issue. I usually fire right away then later when there are more torpedos, they will not fire. A few minutes later they do fire.
Try removing the lockdown bar and playing while activating the leaf switch with your finger to rule out the button. Also activate the leaf switch a few dozen times in switch test mode to ensure it functions consistently. Failing that, maybe a full reload of the game code as a next step.