|Re: HP-41 turn-on behavior|
Message #6 Posted by Vieira, Luiz C. (Brazil) on 9 Jan 2010, 6:46 a.m.,
in response to message #5 by Paolo Cipollone
the 'system' memory loss depends on existing system regular operation. In some circumstances, [ON]/[backspace] is disregarded and the calculator does not clear its own memory.
I prefer the 'hardware' memory loss, because it gives you the closest factory condition. In terms of final memory contents (RAM), once you see [MEMORY LOST] I cannot think of any differences between both, though.
When needed, I open the calculator and short the terminals of the two 'big' electrolytic capacitors in the mainboard. I cannot tell you which one first, but I choose the bigger one first (IIRC, this is the one with the power line). A few days ago I found myself in one particular case: a halfnut simply locked itself inside its own and lost the keys... The display froze with [0.0000] with no visible cause and stayed like like this, no reaction.I removed the batteries for a while, put them back, turned the calculator back ON and nothing changed. I tried the [ON]/[backspace] and nothing. No response at all.
It worried me a lot because it was a halfnut, and they are not serviceable the way the coconuts are. Then I opened opened the calculator and shorted the only two electrolytic capacitors it has. Working fine after about a week or so.
I also have one HP41Cx (halfnut) that has a troubled  key. It fails to work when pressed by the first times, but once it starts working flawlessly it stays like this until the calculator rests for a while. Like if there is some kind of dirty stuff that moves away when pushed (a gel?) but gets back when left untouched. Does it exist or it is just my pride trying to solve a mystery? :^(
Hope this helps a little bit...