We used a wide variety of computers at The Voyager Company. One of those was a Macintosh Iici, which was used in the art department.
The computer started crashing one day while doing random tasks. The folks using the machine tried the various tricks of the day, such as fixing the disk, removing extraneous “inits” (little programs that ran at boot time and patched the operating system to add functionality. Oh, those were the days), removing fonts, etc, but the computer continued to crash.
They finally decided to take the computer to the repair shop, which I forget the name (update: My brother Matt remembered that it was Computer International), but it was on Pico and Earl was the tech. Earl was fantastic and I was sure he’d find the issue. Maybe it was bad RAM or something like that.
After three days or so on “the bench,” the computer never crashed. I am not sure if Earl had cleaned the computer or done any other work, but we were called to pick it up as nothing wrong could be found.
The computer was set back up and it started crashing again. Back to the shop it went, and again, nothing was found wrong. The computer came back after several days and yep, it started crashing again.
I do not recall if someone asked me directly, or if we were discussing it as a group, but we decided that one difference between the office and the shop was that only the computer was being taken to the shop. We decided to take everything in – Keyboard, mouse, power strip, and monitor.
It did not take long for Earl to get the system to crash. He discovered that the monitor had a short inside, and that short is what was crashing the motherboard of the Macintosh.
I learned a lot from this experience – Never assume you know where a problem may lie. It may just be the monitor.