Re: new way to lock up a 41 Message #4 Posted by Vieira, Luiz C. (Brazil) on 3 Feb 2002, 7:52 a.m., in response to message #3 by db(martinez,california)
Hi;
I read your posts and I would like to know:
-did you open the calc? - if so, is it a full- or half-nut?
In any case, there is a capacitor inside the calc (in paralel with the p.s. lines) that can maintain the calc`s circtuits charged for more that a couple of hours IF ON KEYS ARE PRESSED; try short-cirCuiting this capacitor's terminals (DISCONNECT ANY EXTERNAL DC SUPPLIES AND GET RID OF YOUR OWN ELECTROSTATIC CHARGES BEFORE DOING SO); I have solved many MEMORY LOST problems this way
My own HP41C was about 12 months-old (it was young enough I could count its lifetime in months) when the full-amnesia occurred. I inspected the calcualtor later (mine is a fullnut) and the first RAM IC was substituted for a new one. Yes, the first RAM is the one that holds system data, including the 169 all-is-well control flag. As this very RAM was the lost one, nothing could work.
I know this is only info, but may help.
My US$0,02.
Success,
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