HP 11C 'pr error' message


I received an HP 11C as a Christmas gift and do not have a manual with it. When I turn the calculator on sometimes it displays 'pr error' and I have to turn it off and back on to get it to work. I researched and found the self test instructions and keyboard test instructions and it passes both. Does anyone now what this message is? Thanks in advance for your help.



I strongly suggest you get the museum CD/DVD to get the manuals for the HP-11C. I think you will enjoy the machine much more with the docuemntation.

The mesage you got is basically a reset message. The calculator should work fine.


Edited: 6 Jan 2006, 3:28 p.m.


The only time you should see Pr Error is when you leave the batteries out for too long and the continuous memory is cleared.

Based on your description, the unit has either a bad battery contact, bad batteries, or worse, the internal memory back-up capacitor is faulty. It's not a common problem so it's a bit hard to tell what could be wrong if it happens when turning on and off as with normal use.


Hi Randy, Marc, guys;

what about removing the batteries, wait for, say, ten to twenty seconds, then placing them back to the compartment; or simply slightly pushing them away from each other while inside their compartment for just a few seconds.

If the calculator shows 'Pr Error' in these circumstances, then I think that a bad capacitor (or a bad contact with the capacitor terminals) is the best guess. Provided no key is pressed when without batteries, the Voyagers might retain RAM contents for some time, even more than an hour or close to this. In this case, depending on which internal construction it has, resoldering or even replacing the capacitor will not be that hard.

If the calculator passes [ON]/[+] or [ON]/[*] self tests without problems, then I'd guess internals are fine.

Just a suggestion of mine.

Hope you succeed!

Luiz (Brazil)

Edited: 6 Jan 2006, 11:20 p.m.

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