Replacing a fuse should be very easy, first make sure the amp is off. Looking at the back of some Melody amps online it looks like the fuse is in a compartment above the iec power inlet. You should be able to just pop that out with a flat bladed screwdriver and there is your fuse. The value should be on the fuse itself and it's also printed on the back below the iec inlet. Go to Radio Shack or any electronics store get a replacement fuse and pop it in. I concur on the arcing tube which is in and of itself not a big deal but if you're getting noise probably time for a retube anyway. Good luck!
Did I just ruin my amp
First, this is my first tube amp hence the dumb mistake. Over the past few days my stereo has been making an intermittent high pitch squealing sound which I thought was caused by some ground or feedback issue but now see was a power tube dying. Yesterday my wife said she heard some weird sound coming from the speakers. She called me in and I saw what looked like fire in one of the power tubes. I immediately unplugged everything and that is where things now stand. Help on what to do next would be appreciated. I have a full set of extra power tubes which I was thinking of putting in the amp but I wanted to hear from more experienced people before doing this. Thanks.