This is probably one of the simplest yet smartest pranks I have ever heard of. It is simple because of its execution, yet smart because it plays on the engineer's own knowledge of electronics to baffle him. I had a good chuckle thanks to this. The speakers that won't stop playing will be a good story to tell my other friends.
Daniel - http://taylormadeleadership.com
Reminds me of a story passed along from my grandfather, in the days when radio (like many today) meant crystal radio with headphones. He started working on it, and noticed that the sound didn't change. Removing the crystal, disconnecting the headphone wire, and finally removing the headphones. He then found his neighbor had just bought a brand-new (at the time) radio with loudspeaker.
A lovely scientific magic comedy. If i would have been there i would not have opened the cover. I just would have touched the cone paper of the speaker to feel the vibrations and identify or simple put my hear near the speaker grill and checked the direction of the sound coming.This would have given me an easy idea of what is in there.
The old adage - electronic engineers build weapons. Civil engineers build targets...
But you must concede that he found the problem in the usual manner of troubleshooting prowess. Be careful, his future bridges may shoot back...
This reminds me of another hidden object inside a radio. My now EX-wife was snooping through my collection of electronic goodies. She found a small multi-band radio that rattled when shaken. I suggested it probably had a broken ferrite rod antenna piece from being dropped at some time in its past history. Her suspicious detective instincts insisted that she had found where I kept my alleged hash stash hidden from her inside this radio.
I gave her the screwdriver and told her which way to twist the screws to open it up. Imagine her disappointment when the rattling object really was a piece of broken ferrite antenna rod.
The alleged hash stash was never found.