TAD1000 Blowing Fuse

have you tried swapping power tubes? I'm not familiar with that amp, but assume it has a solid state rectifier. Normal troubleshooting would start with the rectifier tube, then go to the power tubes. If you pull the power tubes and power on, and the fuse blows, it's time to take it to a tech. If not, try different power tubes.

blown power tube blows fuse. load your amp with load
resistors instead of speakers and pull all tubes out.
Insert tubes one after another till the fuse blows.

Thanks for the tips, ill pull the tubes this weekend and put them back one by one, as I don't have a tube tester, and see if I can find the culprit!

The safest way is to turn off before plugging in each next tube and than turn on.

I've blown quite a few fuses over the years on the 1000's it was always because of a bad tube. The Tad's are a little rough on tubes. Double check the bias settings as well