Can you tell me if the electronic box 80mm fan was blowing? Some short circuit might have also have caused this, or the 80mm fan of the electronic box being stopped.
On this indeed you can change the transistors, the ref is P55NF0 but you will also need to change the blue terminals.
We can also send you a new board where we can put an additional heatsink on this transistor or we can also provide you with a stand alone SSR 25A DC Static relay to avoid this issue. On my side I've been running without any heatsink all along for about 1 year.