Help in choosing a new calculator

[Ron Ross]

I sympathize with your loss of your Hp 27s. The Hp 35s is not an adequate replacement for you. You need to find another Hp 27s or have yours fixed. Both are costly options.
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If you cannot find an Hp 27s, the Hp 19B or 19bii are probably good options. The downside is a clamshell which is a more fragile calculator in a somewhat larger case (not nearly as large as an Hp 50G though). Another downside is algebraic w/o precedence (called chain logic).

You might also consider an older Ti 85 or Ti 86 (though newer than your Hp 27s). Both will feel much closer to your Hp 27s than anything Hp now offers (aside from the Hp keyboard click). Admittedly these are graphing calculators, but a bit slimmer than the Hp 50G and better laid out for your needs.

Casio made some older pocket programmables, but they were also all single letter variable calculators too (I believe).

Let us know which option you decide to pursue and if you choose something other than another Hp 27s, what your feedback is.