Its a badly made unit as the screws and their holes are missing, so is the heat sink paste, that should be keeping the transistors hard and cool against the heat sink.
So you may be lucky and replacing them will bring the controller back to life. But do add the screws, plastic insulating washers and heat sink paste as well....
As the transistors apparently must not be electrically connected to the heat sink.
Warning, the same transistors,possibly from a different maker, the legs may be not be in the same configuration. So do check carefully before ordering and fitting.
Best wishes
Andy
