No help, other than to say that my V3B did / does the same thing. I recently re-foamed it, it worked awesome for a month of so and has now developed a loud hum, which in turn causes the fuse to blow. Anyway, I'm interested in help too.
Does your hum when you first plug it in before the fuse blows?
I've never experience FULL audio until now. I never knew what I was missing. WOW what a difference.