Funny repair stories?
My Dad was a TV repairman in his first career, and did it on the side for extra money after changing careers.
Once, I was in the basement with him, I was watching a show while my Dad was working on the TV.
The TV started making a "pop" sound.
The picture tube (this was back in the 1970's, when tube TV's were still fairly common,) blew up.
Scared the patooties out of us both, but we weren't hurt.
Took me days to clean up all the glass, the TV was ruined.
My Mom still remembers coming down into the basement after hearing the bang, glass all over, my Dad and I sitting on the cement looking like we both had seen a ghost. 
= new reply since forum marked as read
This is a Mod 40. The printer is on the left.
We had this one Mod 40 in Berlin that would break about once every three months. This is very unusual because Mod 40s NEVER break. Put enough machine oil on the fuckers and they run forever. Except for this one.
There was a female mech named Brenda among our number who developed The Only Way To Fix This Machine. She would come upstairs with her little cart, put the printer on it, haul it to Electronics Maintenance Division, go back where no one could see her perform her magic, and bring the printer back in fine working shape.
Turns out Brenda's magic involved taking the printer to the loading dock which was the only concrete floor in the place, holding the printer out at waist height and dropping it. It was going to either fix it or break it for good, and it always fixed it.
(When we decommissioned the Mod 40s, the mechanics decided to use sledgehammers to get rid of them. It took hours to beat one machine into submission and we had thirty of them. The mechs had real big smiles for about a week afterward.)
I was in the Radar/Fire Control shop, so I only witnessed/heard this second hand.
It seems we had a radio (the Comm shop handled them) that wouldn't work in an aircraft. They would install it, test it, and have to swap it out for another. They'd send it back to MAG for repair and into the system again. The guys in MAG couldn't find anything wrong with it. After several tries, one of the comm shop guys remembered the serial number of the radio and painted one side of it red, so he would recognize it and know better than to try to install it.
It went on for weeks, sending it back to MAG and getting it right back with failure code A799-"No problem found." The guys on the line started calling it the Red Death.
Finally, one of the techs took it out to a plane, placed it on the wing to stage it for installation, and "accidentally" knocked it off onto the concrete tarmac. The wing of an F4 Phantom is about five feet off of the deck.
Apparently, they never saw it again after that.
