If you have a tank query and you can't find the answer anywhere else, post here. (TIP - Check for answers in FAQ, use the 'search' facility or even check this board before posting here).
Forum rules
If your question is electronics related please post it in one of the relevant boards here: viewforum.php?f=31
On mine, you push either the K button or the silver cannon button on top and hold it down, then push up on the left stick. This replaces the safety switch that they used to have. That should get you the cannon firing sound. Keep in mind that when you do this with the tank, it WILL fire the airsoft. There is no just sound function that I could find on the new systems.
You can also switch sounds by using the lower K and S buttons, or the silver ones on top.
Hope that helps a bit.
Bill
"Yeah, but it's a dry heat!"
Private Hudson (Bill Paxton) ALIENS