Hey Jacob, First of all calm down as this is not a serious issue as the bong bong might sound really alerting. I was afraid too, but as I said this is just the LCD issue. In my case, I noticed the LCD that was driving the iPhone crazy (bong bong noise) has bad connectors, 2 of the little things was gone. So make sure you have connected it with care to the board. And never plug them with 'whatever, it will fit into its place' attitude. That was how I ended up with that bad connector! Good luck :) Hope this helps you.
I had the same problem on My iPhone 5s and as it is jailbroken I could do a little bit of investigation. Here is what I have found: I power on the iPhone, bong bong noise comes. I go to the CrashReporter folder and there are a lot of log files. In one of those log files, I saw the following: Jul 12 03:45:43 SpringBoard <Error>: *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'cannot hide defunct contexts without a mainWindow -> screen=1 (connected=0) requester=defunctScreen' (1) First throw call stack: (0x1824f6950 0x18e9fc1fc 0x1824f6810 0x18302edb4 0x10006f304 0x1001ca0e0 0x10008599c 0x1000918bc 0x18692d8f0 0x1824b6890 0x1824b67f0 0x1824b4a14 0x1823f56d0 0x1880d9c0c 0x185526fdc 0x100021da0 0x18efefaa0) Apparently, as indicated earlier, the issue is that there are no screens attached. I hope this helped you! :)