HP-12C bug


Have you noticed the following HP-12C bug:

Clearing statistical registers CLEAR Sigma in program prevents the "running" message.

For example run the following program

01 CLEAR Sigma

02 GTO 01

and compare to


02 GTO 01

This is not a serious bug but a bug anyway I guess.

My HP-12C is year 2003 model (Made in China). Is it the same thing with earlier 12C calculators?


Same thing with my Brazilian 12C s/n 3203B.

Well spotted.



I tried a longer program to check if there was no "reset", but it indeed "clears the display":

f CLEAR sigma
g GTO 01
The 120 + sequnce is just for setting the loop longer and allow "running" to appear, if so. But nothing happens, it acts as if the calculator is switched to off. If it is left in ths condition, batteries wold "drain out" without any warning. Mine is a Chinese unit, Serial # CN1180xxxx.

I have a Chinese Platinum (CN3290xxxx) and this "bug" does not seem to happen: the "running" message prevails.

Good posted.

Luiz (Brazil)


Yep! My 1993 Singapore-made 12C does as you describe.

But, the better question is, "What would prompt someone to write such a program?"

-- KS


This was the shortest possible example to show the effect of CLEAR sigma.

CLEAR sigma in any HP-12C program prevents the "running" message. Add CLEAR sigma in the beginning of any HP-12C program and see the effect!

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