Any circuit with a microprocessor or microcontroller typically requires a clock source, especially if the circuit is a vintage computer! On-chip oscillators were not common in the 1970s and 1980s, and you were expected to either use a discrete clock driver chip with a crystal or create the typical TTL crystal oscillator circuits. Another option was to use an oscillator package, and these were quite common. This little board takes any HC-49-style crystal and converts it into a typical DIP14-sized oscillator!
This can be a great way to quickly get an old machine with clock problems back on its feet. If a system’s clock isn’t functioning, it will usually do nothing at all, leaving you with a black screen and absolutely no indication of what the problem could be. After power supply issues, clock issues seem to be one of the more common failures on vintage machines. Not only does this quickly replace an old oscillator package, but you can then easily tweak the crystal frequency to see if overclocking is possible!
Having a few of these boards on hand with a range of common crystal frequencies means you can easily construct an oscillator just by popping a crystal into the board and then plugging it into the circuit. Pick a few up to stash in your miscellaneous crystals drawer and you’ll be able to quickly whip up any oscillator you need.