"Remember that one bug that had you tearing your hair out and banging your head against the wall for the longest time? And how it felt when you finally solved it? Here's a chance to share your greatest frustration and triumph with the community.
One that I vividly recall occurred back in the early 90's at a startup that was developing custom PBX hardware and software. There was the current development prototype rack and another rack for us in Quality Assurance (QA). Our shipping deadline for a major client was fast approaching, and the pressure level was high as development released the latest hardware and software for us to test. We soon discovered that our system would not boot up successfully. We were getting all kinds of errors; different errors each time. Development's machine booted just fine, *every* time. We swapped out our hard disks, the power supply, the main processing board, the communications boards, and finally the entire backplane in which all of these were housed. The days passed and the system still failed to boot up successfully and gave us different errors on each reboot.
What could it be? We were all stymied and frustrated as the deadline loomed before us. It was then that I noticed the power strips on each rack into which all the frames and power supplies were plugged. The power strip on the dev server was 12-gauge (i.e. could handle 20 amps) but the one on the QA rack was only 14-gauge (15 amps). The power draw caused by spinning up the drives was just enough to leave the system board under-powered for bootup.
We swapped in a new $10 power strip and it worked perfectly. And we made the deadline, too! So, fellow Soylents, what have you got? Share your favorite tale of woe and success and finally bask in the glory you deserve."
An old J-Code Stepper Unit (bonus points if you have any idea what it is).
It was cycling and ghosting so bad we had to drop it off the code line after every time we used it. The local guys dicked around for months trying to fix it with no luck. It was configured by jumper wires on the back. The local boys checked the jumpers against the drawings a dozen times, and always had the same answer - all the jumpers are installed according to the drawings.
One day I stumbled across some very old plans that showed a slightly different jumper configuration, and then it hit me.
I called the local field service guy and got him to the site. He was not super excited about checking the jumpers again, so I really had to arm-twist to get him there.
The conversation kind of went like this - "How many jumpers are on the stepper?" "What?" "Count them, How many are there?", "Okay, fine, whatever, there are 17 jumpers". "How many jumpers are on the drawing?""15 jumpers"
a short pause while this sunk in and then
"Are you fucking kidding me!" A minute later the tech had found and pulled off the extra 2 jumpers and the unit ran perfect from that moment on.