I have a 96 Prosonic that I have used A peavey 115bx cabinet as an extension for several years. I haven't played either one for several years. they just sat. I recently retubed the Prosonic. I turn on the prosonic, then plug int the extension cab and it blows a fuse. Then Today I am playing my 66 princeton and for giggles I plug in the Same cab and the Princeton shuts down. What could be going on? What did I just fry?