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HP Forum Archive 15

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HP-41C and lost memory
Message #1 Posted by Alfredop on 29 May 2005, 6:10 a.m.

Hi,

my HP-41C (I obtained recently) has been not used in the last three weeks. When I turned on yesterday it losts his memory. Battery are ok, and the calculator seems to work fine (apart from the usual problem to stay ON only for two-three minutes before an auto shutoff). Why did it lost his memory? Can this due to the fact that I put the HP-41C in a TI-65 case (I'm joking of course, but maybe ...)?

      
HP-41C and lost memory
Message #2 Posted by Alfredopalfredop.no@spam.libero.it on 29 May 2005, 6:13 a.m.,
in response to message #1 by Alfredop

Ops the case is that of a SR-56.

Alfredop

            
Re: HP-41C and lost memory
Message #3 Posted by Klaus on 29 May 2005, 11:01 a.m.,
in response to message #2 by Alfredopalfredop.no@spam.libero.it

Maybe you held down the <- Backspace while turning it on? Or you coused some trouble inserting a module? I would clean the contacts inside the calc (autoshutoff seems to be too soon), and care for the battery contacts (and new batteries, of course).

Hope the problem doesn't return! Klaus

                  
Re: HP-41C and lost memory
Message #4 Posted by Uliboy on 29 May 2005, 11:46 a.m.,
in response to message #3 by Klaus

As i learned from this forum (pity, ive forgotten which thread, but surely around 2 years old), there are two printed circuit boards inside the hp 41 connected together wich conductive rubber (zebra-strips). The failure of early shut-down is in the contact resistance at this rubber connector. take the 41 apart and clean thoroughly the golden contacts on the pcbs where the rubber connector is located. Use fresh isopropylic alcohol and Q-Tips (see an earlier thread of what these useful things are!)therefore. after reassembly early shutdown, as well as total power fails should be history. Its very simple to perform and by this little surgical intervention i already cured two 41s. Good Luck!

                        
Re: HP-41C and lost memory
Message #5 Posted by Klaus on 29 May 2005, 1:47 p.m.,
in response to message #4 by Uliboy

One should also look at the zebra strips with a magnifier, one copper contact one one end shoted 2 contacts in my 41c.

                              
Re: HP-41C and lost memory
Message #6 Posted by Dia C. Tran on 31 May 2005, 10:35 a.m.,
in response to message #5 by Klaus

May be it's the 56 case. The 56 is a low end programmable from TI and the 41 is the top of the line HP. May be the calc just got mad at you.


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