The fuse is ONLY there to stop your house from burning down when there is a fault. The fuse is NOT there to protect your machne from a fault.
Seems you have a shorted transistor etc etc etc that is placing a large load on the circuit that the fuse is designed to protect.
Remember that when the machine is sitting in game over mode 70VDC is still applied to all the coils and the driver output circuits so a problem could occur at any time when you are not looking.
I would start by studying the circuit and fully understanding exactly what is connected after that fuse - then isolate the connected circuits until you locate the culprit.
