Doesn't sound promising. Unlikely that you "cooked" the speakers with that head, but that doesn't mean that the driver isn't cooked anyway. Things get old, they sometimes go bad.
First, replace the fuse with the proper size. If it blows again, get it to a tech. If it doesn't, but the amp doesn't perform properly, get it to a tech.
The drivers need to be checked. Try playing through them at very low levels, with your ear close to the diaphragm. If the voice coil is rubbing, you should be able to hear it that way. If so, you'll need to get it reconed, or replace it. What is/are the driver(s) in the 1200S cabinet? JBL? D series? Not cheap, either way. There are cheaper drivers available that might sould okay, but not the same.
Good luck.