i am writing in the name of my husband, cause my english is little better 

We have a little problem with our L5 Amplifier. My husband did not use the L5 for a few years. But now he started playing his guitar again an used it for a couple days. It worked fine until yesterday.

The functions like "Reverb", "Frequenzy" and "Multifilter" now sound very strange, and one fuse of the Powersupply blow. (see on the picture, if i get it attached :-)).

I have no idea, where I should start searching for the mistake. I am a electronics technician, so I can measure and change broken parts, but I have no Idea how this amp works.

I checked all boards by looking, could not find any burning marks, or broken parts.. Where sould is start?