[Arran]

I don't even know why a power line fuse is necessary unless you have a lot of lightening strikes or power surges in your area, even in sets with failed power transformers it's usually the high voltage secondary that has failed not the primary, I would be more inclined to fuse the center tap of the high voltage winding. There is a guy on you tube that even installs fuses in AC/DC radios, and with big ugly 20 amp fuse holders, with pig tails, designed for cars, a complete waste of time since the cathode of the rectifier tube already serves that purpose.
Regards
Arran