It’s back in the day, and pilot fish gets an early-morning call. A System/360 Model 65 won’t power back on. The operator tells fish that when he presses the power button, he hears a squealing sound. Could be a mouse, he theorizes, since they’ve been seen around the building.

Fish gives the power button a try, and he does indeed hear a squeaking/squealing sort of sound. Fish figures the quickest way to find the problem is to follow the sound. He has to get around a large structural pillar before he can get anywhere close to the place where the squeak seems to be coming from, so he asks the operator to push the power button while fish takes a look.

The operator complies, and as fish is coming around the pillar — BANG! — a metal projectile blows past his head and smashes into a wall several feet away. Fish has to wait for his heartbeat to return to normal before he can even think about investigating further — and he figures too that he should wait a bit to see if any other missiles are heading his way.

When he does get behind the machine, he immediately sees the real story. A capacitor had shorted in the inverter/converter. When the power button was pushed, the capacitor released excessive pressure from its container — and squealed. And when the power button was held down while fish made his way around the pillar, the pressure became so high that it could not be released, so the internal guts of the capacitor blew out. The 65 provided plenty of propulsion. And those capacitors are BIG, about 3 inches in diameter and 7 inches long.

All in all, a lot more dangerous than a mouse.

Sharky squeals with delight when I read your true tales of IT life. Send them to me at sharky@computerworld.com. You can also subscribe to the Daily Shark Newsletter.