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78 PCB007 MAGAZINE I JULY 2021 Welcome to the grand illusion. ere I was, mid-1986, and in my first job with printed cir- cuits. I knew what circuit boards were but had no idea about all the processes involved in their manufacture and test. Here in the Pacific North- west, there were probably two dozen PCB man- ufacturers producing everything from double- sided to 16-layer stacks. All were PTH-only at the time. Surface mount technology (SMT) was not to make its debut for a year or two. Fixture testers were 100-mil grids (0.100") and there were no such things as double-sid- ed testers. What? ere was no need at this point as SMT was not active. Test fixture manufac- ture was simple. You could either use the production drill file or al- ter the tool sizes for the test pins and drill. Once complete you could lay the plate over film and X-out the vias. Or you could dig- itize the outer layer and optimize mid-points and vias. Either way, you would then assemble the fix- ture and it was ready for the tes- ter. ere were no netlists back then, only self-learn or "golden board" learn. As time progressed, SMT ap- peared on the scene and changed everything. Technology had evolved, and the PCB industry had to react to new equipment, processes, and ways to man- ufacture. ET had to evolve as well, such as with double-sided fixtures for sin- gle sided testers, and spring probes and wires translating the top-side fixture down through the bottom to the test field. is was expen- sive. However, the industry was booming on into the 1990s and life was good. Ever yone was enjoying the returns and competition was flourishing. Competition in an open market is good as long as margins remain safe and technolog y continues to advance. However, something went ver y, very wrong. The PCB Limbo—How Low Can You Go? Testing Todd Feature Column by Todd Kolmodin, GARDIEN SERVICES USA