HP 20S Self-Test Question


I bought a "brand new" hp20s today from a stranger for $25. The package was "open box", but inside everything looked new. I've used a hp48sx since '91 and when it came time to buy my kids a scientific calc, I thought the 20s might be a good one.

Anyway, the calc displayed some random digits (mostly zeroes) on its screen when I turned it on and they would not clear. I performed the self-test found in the manual and got a "20-FAIL 8" error message, which the manual says means that I need to have it serviced.

I searched the HP site and found how to reset the calc. This worked and the screen display returned to normal and everything seems to work fine. HOWEVER, when I do the self-test, it still gives the same error message.

What do you think? Does it still need service or do I just ignore the message? Thank you for any insight!


Hello !

In performing the self-test, I get the same results at my HP-20S !.
It works properly, so I do not think its any wrong with Your calculator.

Edited: 11 July 2008, 9:01 a.m.


Well, that is reassuring! Thank you! ~Karen



I tried my wife's HP20S ( I need RPN !) and it gives me "20- good". However, it took me a number of attempts to get it right and each of those gave me "20- fail 8". It's probably fine but you could try resetting it as described in the manual and retrying if it really bothers you.



Got it!! It says Good! Thanks everyone! ~Karen

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