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HP Forum Archive 13

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HP41CX - hard reset
Message #1 Posted by Richard McDonald on 3 Aug 2003, 4:05 p.m.

Hi there; The net of my question is "what's the keyboard sequence required to induce a 'memory lost' reset in an HP-41CX. My old, failing memory thought Enter/clx/on would do it, but it doesn't seem to work. I also left the batteries out for 24 hours and that still didn't cause a "memory lost" reset. That was odd.

I'm trying to resurrect my HP41CX that I've owned about 15 years. It's been stored in a dry location, in it's case and I've replaced the batteries periodically.

The last time I replaced the batteries it wouldn't power on correctly. A series of Enter/clx/on sequences will sometimes bring it up after removing the batteries for a few moments. Once I get 0.0000 in the display, I have control of the keyboard and can execute most functions. The display seems fine. Pressing keys and the sides doesn't cause a flutter so I think the contacts are ok. So I think the program memory is messed up and needs to be reset. A PCLPS doesn't seem to clear the offending problem and doesn't seem to complete (I don't see "packing").

Comments and recommendations are most welcome.

Richard McDonald

Re: HP41CX - hard reset
Message #2 Posted by Ernie Malaga on 3 Aug 2003, 4:15 p.m.,
in response to message #1 by Richard McDonald


The hard reset is called "master clear" and is performed by holding down the correction (back-arrow) key while turning the machine on. This feature clears continuous memory and resets flags to their default states.


HP41CX - small remarks
Message #3 Posted by Vieira, Luiz C. (Brazil) on 3 Aug 2003, 5:31 p.m.,
in response to message #1 by Richard McDonald

Hi, Richard;

just to add that PCLPS will be effective if executed while at least one program is the current one OR if an specific global label is in ALPHA register. If ALPHA is empty and the calculator is "positioned" to the last program in memory (the one with the permanent .END.), nothing will be cleared. It's also important to keep in mind that all programs after the one you clear with PCLPS will be cleared as well.

As Ernie mentioned, the "Master Clear" procedure is the standard "clear all" resource for the hP41 series, and you should see

if you succeed performming it. As you mentioned, if you pressed [ENTER][CLx][ON] and nothing happend is because this is not the correct sequence; please, do as Ernie explainned and you'll probably achieve a memory clear.

Success. Should you need more advice, please, let us know.

Luiz (Brazil)

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