According to [MTSI], if you used a Z80 chip back in the 1980s, it almost certainly passed through the sole Fairchild Sentry 610 system that gave it the seal of approval.

The Sentry was big iron for its day. The CPU was a 24-bit device and ran at a blistering 250 kHz. Along with a tape drive and a specialized test bed, it could test Z80s, F8s, and other Mostek products of the day. There was a disk drive, too. The 26-inch platters stored under 10 kilobytes. Despite the relatively low speed of the CPU, the Sentry could test devices running up to 10 MHz, which was plenty for the CPUs it was testing. The actual test interface ran at 11 MHz and used an exotic divider to generate slower frequencies.

According to the post, an informal count of the number of chips in the device came up with around 60,000. That, as you might expect, took a huge power supply, too.

From some 1975 corporate literature:

“Optimized for engineering, sophisticated production needs, QA and test center operations, the Sentry 610 is the most versatile analytical tester available for engineering and production. It can perform the widest range of tests for the broadest range of components. At user option, the Sentry 610 can perform high-speed MaS/LSI, PCB, and bipolar tests simultaneously. It offers complete testing at the wafer level and through automatic handlers at full-rated device speeds up to 10 MHz. The wide choice of peripherals gives the Sentry 610 system massive data handling capacity to manipulate, analyze, compute and generate reports on test procedures in analyzing MaS/LSI.”

These days, you are as likely to stick test hardware on the IC as have a big machine on the outside. And even then, you probably wouldn’t have something this elaborate. But in its day, this was high-tech for sure.

The Z80 sure has had a long lifespan. It shouldn’t surprise you that Z80s need to be tested, just like everything else.