I will add to Eds comments.
First watch a few SMPS U-tubes & and get to know how they
work. Pick simple ones. There are some real monsters !!
There are several styles so pay attn to the block diagrams.
Blown fuse is usually the power FET, the bridge or MOV if it has one.
If the bridge is bad change ALL FOUR at once.
If the FET is shorted you need to find why. Usually lightning but
other possabilities. Often boils down to gambling an FET or not.
On yours the burned area is VERY suspicous
73 Zeno
LFOD !