Well, normally calculators are disposable. Alas I found this Novus 821. Before this point I never realized that this was actually National Semiconductor's consumer electronics division that actually made ... calculators. Also the really old Nat Semi logo, I finally realized it's an N and an S, I was wondering what those two squiggly squares were.
Anyway, why this calculator was interesting? It has an LED display instead of the typical LCD!
Alas this thing isn't working that well. What was kind of odd when I looked at the guts, this thing has NO capacitors in it at all! Not one discernible!
Anyway I wouldn't have posted here if it didn't have problems: it, well, doesn't work 100%. First it doesn't reset on powerup, forcing me to press "C" every time. The other thing is that the LEDs go wonky. Sometimes I do wonder about the ICs in this thing, this should be a rudimentary processor with built in firmware I guess... and could the firmware actually go bad?
It has exactly two ICs in it: MM5738N and DM8864N - and both are made by Nat Semi of course.
Anyone have experience with these really old calculators? I guess this would be about 40 years old now... though I've had other ICs that have lasted longer than these.
Anyway, why this calculator was interesting? It has an LED display instead of the typical LCD!
Alas this thing isn't working that well. What was kind of odd when I looked at the guts, this thing has NO capacitors in it at all! Not one discernible!
Anyway I wouldn't have posted here if it didn't have problems: it, well, doesn't work 100%. First it doesn't reset on powerup, forcing me to press "C" every time. The other thing is that the LEDs go wonky. Sometimes I do wonder about the ICs in this thing, this should be a rudimentary processor with built in firmware I guess... and could the firmware actually go bad?
It has exactly two ICs in it: MM5738N and DM8864N - and both are made by Nat Semi of course.
Anyone have experience with these really old calculators? I guess this would be about 40 years old now... though I've had other ICs that have lasted longer than these.
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