These are two bridge rectifiers that are wired in parallel, each can handle 30A so they should be more than OK for the 30A max input currents. But notice the small hole at the bottom right, yep it's fried!!!!
And wow, it blew a small hole out of the aluminium heat sink, impressive!!! I've now taken the rectifier off the board and have discovered the first real problem. It is no longer made and worse, the pin out is non standard!! It sits a fair way off the board so I have to hope I can find a way to make some sort of adapter for a new rectifier, we shall see. And lastly, a few photos of the insides for context: