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!