Iago,
One of my friends ran a electronic's repair shop for 15years. What he taught me is that when a fuse gets blown, it's usually for a reason. A short, bad power supply, lose cables, bad solder, etc.
I've now repaired a handfull of TV's, speakers, and misc other equipment. One of the things I am always doing is scraping away the solder residue on the circuitboards.
Explaination: After a period of time, from my understanding, solder points tend to heat up a little bit, and excretes a conductive material. This will slowly creep and can bridge connections on the circuitboard, thus creating a short, which can blow the fuse. So what I do is take a look at the circuitboard for any brown residue that is around the solder points. If you see it, gently scrape it away with small flathead screw driver.
Also, take a close look at the circuitboard for any hairline cracks. If you see any that break any of the electrical paths, you may have to solder a wire to fix that.
Be sure to disconnect the power before doing any of this.
There are more things you can do if you had a volt meter.
Reorx
ps: I know my terminalogy isnt 100%, I can't remember all the proper terms.