Hello Ragnar22,
Since the fuse has blown quite violently, you may have many components that have failed.
Please see below modified schematic on the components that need to be checked regardless.
There's is a good possibility that the feedback circuit (around opto-coupler) has triggered a false
feedback voltage, causing an over current situation.
I would recommend you lift one leg on any of the diodes you want to check to ensure they are not leaky
by performing a punch-through test.
Since the supply isn't vastly complex, it wouldn't hurt to check any of the other components, especially those
in the primary side of the PSU.
Please take special note on Brian's comments, especially the main filter capacitors, as they can store a hefty charge.
You can discharge them using a 5 Watt 100 ohm resistor, this will discharge them without the sparks.
Please let us know what you find and how you get on.
Good Luck!!! :wink:
Regards,
Relayer