Tek 310A sillyscope

A manual for your oscilloscope can be found at: www.w7fg.com for $25 bux. I also second Tony Duell that it is unlikely the power transformer would have failed, especially in such a small and lightly-loaded device. But locating and removing the B+ secondary leads from the rectifier components (probably selenum in that vintage of a scope) will begin to isolate the problem. Also be very aware that shorted and/or arcing selenium rectifiers produce copious amounts of deadly (and stinky) hydrogen sulfide gas. (The same gas that makes rotten eggs so odiferous) Be thankful that it's a catasrophic, fuse-blowing-instantly type of fault - which will have a definite unmistakable cause and a hopefully easy remedy. But isolate the HV leads first, then the filament leads if the fuse still blows. Also verify that the proper value fuse is installed. I chased my tail all over the workbench trying to find the 'problem' in a Hewlett Packard VHF signal generator, only to realize that the fuse holder was clearly marked "4A" and someone had put a 1-1/2A fuse in it, which, of course, blew as soon as the voltage hit the tubes - and which I dutifully kept replacing with one of the same value as the blown one as I methodically and carefully 'troubleshot' the damn thing. D'OH!!!! Cheers John