Commodore SR4921 RPN


I was surprised to find a Commodore RPN calcualtor - the SR4921 RPN.

Look for it in this museum:


Do you know the Commodore 'Minuteman *6',
and the 'Minuteman *6X' ?
The latter has even an ENTER key.



I remember receiving the newspaper clipping of an ad for a Corvus calculator with RPN. This must have been around 1974-75, and the newspaper was from Los Angeles, CA.

Does anyone remember it? If I remember well, it was about equivalent to the HP-45.



I have one of these and remember how much they used t advertise against the TI SR-51A slide rule calculator.

It has trig, logs, couple of conversions. I searched long and hard for one of these. Like to have never found it.

The thing I remember most is that they used to have a chart comparing features with the SR-51A and it was about the most misleading thing you could imagine. There was a footnote at the bottom that indicated all the TI specs were taken from the SR-51A manual. Well, only if read by someone with their eyes closed! :-)



>The thing I remember most is that they used to have a chart comparing features with the SR-51A and it was about the most misleading thing you could imagine.

I agree. The Corvus 500 may be comparable to the HP-45, but not to the SR-51A.

Thanks for sharing the link. I'm glad I ended up having a 51A and then an HP-25.



I'm working on an online calculator catalog for users and the first user to upload a calculator, uploaded a 4921.

Commodore 4921

I'm hoping to have a version up this weekend that will have the look and feel of the demo shots. It will eventually be fully searchable with thumbnails for quick loading.

Stay tuned!


An interesting coincidence!

I would like to find one to buy as I have several other Commodores.


I actually have this calculator. I was fortunate to win the auction on eBay. Not a bad looking calculator and it does use a 9 Volt battery, so I had it fired up and working pretty quickly.


How does the register stack compare to HP's - number of levels, automatic lift, does rolldown rotate the registers etc. I see it is a "red dot" - makes it more valuable?!


The SR4921RPN has a four level stack: X, Y, Z and W (instead of T). It operates similar to the standard HP stack, except the W register does not copy into Z upon an X and Y combo function (like addition, etc). The roll down is the same as HP. Mine has a red dot, my guess is that they all do....


What ends up in Z after a 2 argument operation? Does it "repeat" like T on HP calculators? Then you could still do the constant operations by filling the stack. Although it's different, I kind of like the idea of an independent stack register, as W seems to be.


Hi Mike, did you get the manual with it?

Would you consider sending me a scan (300dpi colour) of the calculator and manual if you have it?


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