HP 12cP25thAE Self-Test Result?

I was wondering if anyone who has a HP12cP25thAE could run this test and verify what I am seeing.

When I used to run a self test on my 12cP25thAE by pressing {g}+{ENTER}+{ON} sequence and then pressing on [2] for the "C" option, I used to just get the Checksum message "ChE--564Ah", then press [ENTER] the copyrigth message "C 2004 hP".

Now I am getting "UEr 02" after the checksum and before the copyright message. I don't recall seeing this before. Does anyone have an idea?


This is normal, it's always been there on the 12CP 25th AE. It's not like the 12C+ or the 15C LE.


Hi Katie,

Could you tell me what the fourth item on the menu ("4.CPU") is for?

When chosen, the information presented in my unit is : 3999310 h2




I wish I could but it's a mystery to me too. Another person here pointed out that this number changes each time you press 4 from the menu. Actually I find that it doesn't change each time, but most.


I just did a little testing and think it's a clock speed indication of some kind. As the calculator warms up (hold in in your hands for a while) this number gets smaller. As it cools down (put in the in refrigerator for a minute) this number get larger. You need to be patient with this becasue it takes a while for the heat to penetrate into the chip, but simply CPU clocks are usually very temperature dependent just like this.

Anyone else want to hazard a guess?


Thanks Katie for the response. I wonder what does "UEr 2" means in that message, User 2? U Error 2? wild guess.

Also about the 4.CPU option, i think you are correct. It seem to correlate to what it seem like a CPU speed. I also confirmed that hot makes it go lower, cold higher. Alhtough I beleive 12cPAE had a Sunplus 6502 processor which was running at 1MHZ. I wish there were more information on these messages and how to read the self test results, you may remember TW commented that on the checksum FF=FF is good which is not the case for the 12cPAE.


"UEr 2" - I read that as "Version 2".

Yes, the checksum is totally different on the 12CP 25th AE.

I don't understand the need to show some sort of clock speed indication unless it's possible to run at different speeds. But the "h2" on the right side of the display might be a clue as to the meaning.

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