***" Hand wired fuse not to blow"***
What, exactly does that mean?
A fuse blowing IS NOT A DEFECT.
It indicates that there is a serious defect in the electrical system and the fuse is blowing to protect the electrical system from further, even more serious damage.
If we can get enough info from you, perhaps we can help steer you through diagnosis and repair, but we can't help you reconstruct your tractor after it catches fire.
The fact that a shop "suspects" a bad PTO switch, and changed the switch..............might mean the PTO clutch itself is shorted, or a short exists in the wiring leading to the PTO clutch.
There are specific tests that can be done to help determine that.
Post the full technical model number of the tractor so that we might find the schematic for your tractor online.
This number is usually found under the tilting seat on the chassis.