[Robert Morrison] had an ancient HP 545A logic probe, which was great for debugging SMT projects. The only problem was that being 45 years old, it wasn’t quite up to scratch when it came to debugging ...

In the mid-1970s, HP developed a set of three handheld probes; a logic probe (HP 545A), a current pulser (HP 546A), and a current tracer (HP 547A). These were replaced later with the updated HP10525T ...

As I mentioned in my recent columns on the topic of adding pull-up or pull-down resistors to the inputs of unused or partially used logic gates and functions (see Part 1, Part 2, and Part 3), I was ...