ID an electronic component ??

[TASP]

Put on your thinking caps.

I think it was back in the 1980s, I saw a new product announcement in High Fidelity, or Stereo Review, or Audio, or some other hi-fi related publication, of a little device you could put on your turntable (for the younger readers here, probably best to give up on this thread now, sorry) that would monitor the operating time on your stylus. (I'm not kidding, younger readers still on this thread need to bail now, it will get worse).

As we old farts recall, a worn stylus in the groove of your vinyl LP would impair the fidelity and damage the record too. Any how, this particular timer was really simple; not counting electrons, it had one moving part. As I recall, it was a thin glass or quartz tube, maybe an inch long, with a tiny bead of mercury (or something in it), and it was wired to the turntable motor. In operation electrons would very slowly evaporate (or push?) the bead down the tube and it took hundreds of hours, and that interval was comparable to the lifetime of a stylus. When the bead hit the end of the tube, you replaced the stylus, and flipped the tube over, since it took the same amount of time to put the bead back, it was just easier to do it that way to reset the 'timer'.

Anyhow, not much need for stylus hour meters these days, but that device was super low power draw, did something useful (kept track of operating times in the hundreds of hour range) and I'll be damned if I can remember what the tube was called. I've tried googling every permutation of all the keywords I've used in this post and come up with nothing.

Annoyingly, I have kept all my back issues of all those hi-fi magazines, but without a comprehensive index, I'll never find the issue in the remainder of my lifetime.

I think it's odd, something that useful never found wider use in other applications or at least some fleeting mention in wiki, or on the net somewhere I could find, but to date, nothing.

Anyone here ever learn of such a device? What it's called? Why did it never find wider use?

Appreciate anything anyone recalls.