Brother printer = thermal fuse blows

[paulscarbs]

Hi,
I replace the thermal fuse but it instantly blows. A different power supply from another Brother printer works in faulty unit.
Diagnosis so far is a faulty power supply.

What might continue to blow the fuse?

 

[paulscarbs]

Update, it seems two diodes and a transistor are faulty.

I'll replace and update on progress.