1. You have a sound file on your SD card that plays the cannon sound, but you gave it the file name for something else (in other words, something other than "cannonf.wav")2. Or for some reason the TCB is sending the signal to fire the cannon at the same time it sends the signal to start the engine. For #1, I would put the SD card into your computer and listen to all your sound files once again, just to verify that the cannon sound didn't somehow get named to something else. For #2, examine all your function triggers in OP Config. Did you maybe link the "Cannon Fire" function to the "Engine Start" trigger by mistake? Did you maybe assign the "Cannon Fire" function to the same switch on your transmitter you are using to start the engine?
You can post your OPZ file if you want me to look at it.
There is something else I noticed in your video, which may or may not be related to your problem. I notice there is a delay of several seconds from the time you flip the switch on your transmitter, to the time when the engine starts. Do you know why that is?
By any chance do you have an engine "Preheat time" specified? (In OP Config on the Motors tab, under the Smoker section, when Type is set to "Separate Heat & Fan").
On your SD card do you have a sound file called "preheat.wav"?
Hi Rongyos, if I understand you correctly, the cannon fire happens when the TCB first starts. And this involves not only the sound, but also the recoil servo. If that is the case, then we can eliminate the sound card as being related to your problem, it is clear that the TCB is the one firing the cannon.
Plug your TCB in to your computer with a USB cable and connect to it with Snoop (on the Firmware tab of OP Config) to see what is happening. Does the TCB report a "Cannon Fire" event when it first starts?
I wonder if maybe you have Aux Channel 6 in Position 2 when the TCB starts? I see you have Aux Channel 6 set to "Reversed" in OP Config. Maybe un-reverse it in OP Config, and reverse it in your radio's settings. You can also try changing the cannon fire function to a different aux channel. I can't say what the problem is, but I am confident it is not an error in the code. Somehow the TCB thinks that the cannon should be fired, which implies that your radio is telling it to. You will have to do some more troubleshooting yourself. Even if you don't solve the problem right away, hopefully you can discover a piece of information that will help us solve the problem.
What software are you running on your TX16? If it is OpenTx, here is a video on how to set the failsafe values. I don't know if that is your problem or not, but you could experiment with it anyway. You will want to set the failsafe position of Aux Channel 6 to position 1, so that if the connection between the receiver and transmitter is lost, or hasn't been established yet, the cannon will not fire.