So we've been manufacturing Nixie Clock kits for the last few years, and for the multiplexers we used 74141 ICs, or their Soviet clones (К155ИД1). The latter were easier to find on ebay and were used more commonly. These chips have a date code like "8910" which I assume to mean year 1989, week 10.
Since this is all NOS (New Old Stock), I've made a 74141 tester to verify incoming batches.
I received the latest batch of chips yesterday and to my surprise about 1/3 of them failed the tests. Then I noticed that these new chips were visibly different: the plastic package is more edgy, there's some sort of manufacturer logo, and their date code is "1814"!
Compared to an old one at the bottom right:
I later verified that the new chips work on actual nixie clocks, but my tester rejects them for some minor reason (probably the new ones are a bit more sensitive to supply voltage, they also seem to be consuming a tad more current).
- Which manufacturer is this?
- Is it really possible that these ICs from the sixties have just made a comeback?
The practical upside of this is that we'd be curious to contact the new manufacturer directly, to cut the ebay middlemen.