Who needs instructions.....Are you sure sir ?

A friend of mine just rang frustrated that he had just ruined his Hi-Fi, when he started "playing" with it. On the qustion what happened he said "Just lifted the back cover..... There was a small silver box with KAU-Tion.... (his english are not existent but who i am to laugh for that..lol). DO NOT DISASSEMBLE.
On my suprise he said." I forced the cover played with the wiring, put back all....(exept a couple of odd screws that could not figure out how he left them spare!!!), turned it on and went with a flash and a bang".....So here was the killer question.
"Why me?.....What did the box say anyway......"ps the greek instruction clearly stated that this should not be tried or the guarantee would be void. Nowdays they have the "chastity belt" on certain components and they do know the idiot.