First, Why are you running a power inverter?
Second, You need a fuse on the power wire near the Bat going to the amp.
Third, The ground should be grounded next to the amp to the chassis.
Fourth, buy your self a DMM and learn how to use it.
The amp pos. should connect via a fuse to the cars battery pos. NO INVERTER.
The amp neg should be connected to the cars chassis within 18' of the amp or so.
If you hooked the amp up to an inverter and sent 120 volts ac into it at 60htz, then it may be fried. But if the fuses popped, then it may be ok.
Hook it up properly and try not to fail anymore.