Console malfunctions 20 years ago were quite a different calamity from today. With nearly everything in them proprietary parts or technology, repairs had to be performed by licensed technicians with another piece of proprietary equipment. Here's a look at one such toolkit.
Courtesy of Rerez, this is the Super Nintendo Counter Tester, a huge block of ports and switches that could isolate whatever it was bothering some poor kid's broken down SNES. As Rerez explains, often the solution was some component plugged into or bolted onto the console, not a problem with the core technology, requiring a full console replacement.
Who knows how they got their hands on this thing (or why). It's not a development kit, and the only secret applications it appears to run are things like "A/C Adapter test." Still, it's a quirky look back at a different era in gaming. Other consoles had test/repair units, too, but they weren't as user-friendly as Nintendo's and, that, suggests Rerez, was another key to the NES and SNES' long success in North America.