Calculatorsource has 35S fir $500. looks like HP replacement is 42S for $300 so looking for non HP with RPN. Swiss Micro DM42 is also $300 I got my 35 working!
There are lots of RPN calculator app or programs. RealCalc on Android, Orpie for Linux/MacOS/BSD CLI, or for a more full-featured GUI application Qalculate is extremely capable (even includes propagation of uncertainty & interval arithmetic).
Sorry to hear about your calculators! If you're looking for something similar to the HP 35S or 33S, I’d recommend checking out the HP 50g. It’s a solid, high-quality scientific calculator with a lot of advanced features, including programming and a similar feel to your older models. It's definitely a bit more advanced, but it might be a great upgrade if you need more power.
Given the choice of having a separate calculator or an app on the phone, I'd choose the app for several reasons
> You almost always have your phone at hand, while a calculator is often wherever you used it last
> I carry two phones already, so another phone-sized object is not feasible
> Your phone can carry huge numbers of apps in addition to your calculator, like spreadsheets, other math apps, Word docs, etc.
I've got multiple calculator apps on my phone. And some on my computers. And physical calculators. Sometimes it's nice to not need to swap what's on screen, and instead just swap to a different device. Definitely worth having a good phone app or two (or eight, maybe I have too many) for convenience though.
RealCalc (most used, it's a very nice RPN scientific calculator with good unit conversion capabilities)
TI-89 emulator Graph89 (with an RPN application)
BitCalculator (handy for bitwise calculations, can show all 64 bits of a value at once, signed/unsigned integers, 8/16/32/64-bit widths, big/little endian, and IEEE 754 single & double precision floating point)
WolframAlpha (online-only, but very powerful)
ConvertPad (dedicated unit conversion calculator)
HP-48 emulator Droid48 (replaced by RealCalc, never deleted. Familiar button layout)
Electrodoc Pro (Electrical & electronics calculator & reference app)
Slide rule emulator, for silliness. If you can't pull out your phone & use it as a slide rule, are you really calculating?
I've got two physical TI-89s, a TI-36x solar, and an HP-48.
