ClockInACan Is a Configurable Crystal Oscillator IC Replacement for Crystals You Can't Quite Find!

@TubeTimeUS over on Twitter is one of the accounts that is great to follow. Known for more often than not, taking us on a stroll down memory lane, to the land of long lost and forgotten designs and devices of days gone by, they are one of the accounts that certainly brighten up my feed with their posts that feature the fun foibles and follies of yesteryear!

From day to day dealings with such older designs, it's clear that one thing @TubeTimeUS probably knows a great deal about about is component obsolescence. The plague of repopulating any BoM line for a more modern time, with more modern components that are actually available to source right now is often not without problem.

With some parts up-revisioned in ways that forgo certain former package options, or voltage capability ratings, it pays to be extra attentive when trying to source certain components needed to breathe new life into old circuits.

At best, a casual oversight in your spec comparison could mean an older device fails to function, and at worst, you might find yourself adding a blue smoke refill kit onto that parts order of items of ever increasing scarcity!

So rather than relying upon the rather rough-n-ready levels of quality in the quest to source these parts from questionable sources of !"factory seconds" stock, why not instead consider the idea of crafting your own, functional replacements? And if you're a purist, as TimeTubeUS is, you'll be chasing that form-factor fit, meaning you can drop your new functional replacement parts straight into place on the original product.

In one of the first of what we hope will be many modern day takes from TubeTimeUS on tackling component obsolescence, we present you their ClockInACan, a nicely designed clock source crystal replacement for quartz timekeeping devices that just aren't produced in such gargantuan packages any more!

Based around a JRC NJU6311, and accompanying quartz crystal, this nifty circuit is more than just a single frequency source. The IC exposes a set of strapping pins, which are bought out to the row of pads seen bisecting the PCB layout above.

Mapped internally to an output clock divider, these 3 pins allow the selection a range of clock divisor settings, from ƒ/1 to ƒ/32. Rather than being limited to the specific fundamental frequency of whatever crystal you can find, your options are now greatly expanded when it comes to choosing a quartz oscillator, with respect to your target output frequency.

In terms of drop-in replacement, we have to draw attention to the selection and use of specific, turned pin contacts — in place of the single segments of 0.1" header strip that some of us would be tempted by.

While header strip is gong to be fine for breadboard usage — it's not going to be a universal fit in the receptacle contacts of a DIL-14 socket, that was designed for the much more svelte leg of a crystal oscillator can.

Thankfully, there are a myriad solutions for such specific specification contact suppliers, and one of the better known names in that game is MillMax. So it's no surprise to see one of their product range of turned pin contacts turning up here, a P/N of 0542-0-00-15-00-00-03-0 is put to good use in this project!

While far more expensive than header strip, the function offered by these sorts of contacts — being able to make reliable contact in these retrofit applications — makes the extra cost easier to sink into the context of the project aims.

Granted, I've drawn a lot of attention to the retrofit aspect of this project design. Targeting a commonplace, but not universally used DIL-14 Crystal Oscillator "Can" package, you might be asking what of the perhaps equally commonly employed "half-can" DIL-8 crystal designs? Not to worry, the ClockInAHalfCan has your crystal cravings covered!

Also of note in the above image of ClockInAHalfCan is the ability to choose between various crystal packages for the source oscillator of the NJU6311, further increasing your chances of being able to cobble together the required clock source from whatever components you can currently cop!

This is a neat, well-thought-out example of well-executed engineering in response to component obsolescence that would perhaps otherwise enrage enthusiasts of more obsolete equipment...

With a well-documented project repo read-me, and production / source files furnished with validated supplier part listings, this is one to keep in the favorites folder for the future, for when you might inevitably find yourself facing the frustrations and fraught successes in failing to find "NRFND" parts.