On 2023-12-13 22:52, Mouse wrote:
But a drift of a couple of % would not be unexpected.Um, yes, it would be unexpected. The crystal spec in that era was 0.01%, [...]If you see a couple % drift, that's definitely not the crystal.I'm not so sure. My experience is that older machines keep worse time than newer ones, even high-quality older machines and cheapo newer ones. I suspect that crystal frequencies drift with time (or perhaps with something that tends to correlate positively with time, such as wide temperature ranges in storage).
Chrystals age, and over time get farther from the nominal frequency. They also deviate based on temperature. And a bit on load. So I would say more than 100ppm is definitely more or less to be expected.
But I might have exaggerated a little when I said "several percent". :-)But just pull up the data sheet for any modern crystal, and you'll find what the expected deviation will be based on both time and age. (Well, actually, for age they usually just say what to expect the first year, after that there isn't much...)
Johnny
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