If the 5 Volt fuse blows each time there must be a defective circuit, this 5 Volt line is stretched out for a lot of things, the optical sensors use them om playfield (the sensors for the file cabinet) your dmd uses it etc. check those first by disabling them.
Good luck the 5 Volt circuit is a tircky one, there also is a pot meter on the mainboard that regulates the 5 Volt maybe it is set too high (measure at J113 or j114 i think)