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CASIO fx-4000P scientific calculator from 1986
12-21-2015, 12:32 PM (This post was last modified: 12-21-2015 12:35 PM by Chasfield.)
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RE: CASIO fx-4000P scientific calculator from 1986
This is my hierarchy of preference for calculator keyboards:

1) Positive tactile action and reliable (my HP11C)
2) Mushy action and reliable (my Casios and Sumlock Anitas)
3) Positive tactile action and unreliable (my Texas TI59, HP30B, and Sinclair Scientific)
4) Mushy action and unreliable - quite rare, I think

Ergonomically speaking, the worst keyboard I have is on my Novus Mathematician. It provides no tactile feedback whatsoever and the spring rate is unpleasantly non-linear, giving the feeling that the key is about to snap off at the limit of its travel. However it responds reliably and doesn't generate double presses.

I think Texas scared quite a few customers off around about the time of the TI57 (and its numerous cousins rendered in similar hardware). Those were very poor units and, in the main, their leaky NiCads sent them to an early grave.
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RE: CASIO fx-4000P scientific calculator from 1986 - Chasfield - 12-21-2015 12:32 PM

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