A blown fuse is the first and only thing I've had go wrong with either of my Echo 1 M4's, happened 2 weeks after getting my first one. Fortunately for me, I'm an instruction manual reader (not to mention that the Chinese translations are hilarious) so I had remember that these things even have fuses. Mine was a 20 amp as well, went to Autozone and got a 5 pack for like $3 and I now carry the extras with me in my gun case.
phxflyboy