HP Forum Archive 17

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Program Loss in HP-33S Message #1 Posted by Ed Look on 6 Apr 2007, 4:47 p.m. I went to use a program in my 33S just about a hour ago and I found all my stored programs gone! I am quite certain I did not erase them and I cannot imagine any accidental keypresses that would do that. Has anyone had this happen? (Does anyone have an explanation??)

Re: Program Loss in HP-33S Message #2 Posted by John on 6 Apr 2007, 4:53 p.m., in response to message #1 by Ed Look Electronic devices can have many things happen to them. A stray gamma ray might hit the one bit of memory it uses as a cold start constant. The battery power may have been interrupted unbeknownst to you and cleared ram. If you have two 33S calculators, you may have picked up the clear one. (Being hopeful here). But really, anything that relies upon battery power always runs the risk of memory clear. That's why offline storage or flash memory is so important.

Re: Program Loss in HP-33S Message #3 Posted by Palmer O. Hanson, Jr. on 6 Apr 2007, 10:09 p.m., in response to message #1 by Ed Look I lost memory in the first of my 33s machines by failing to see the battery annunciator which is easy to overlook because it is small and tucked up in the upper right corner of the display. I also failed to recognize that when the battery power is very low I would find that the machine may shut itself off but I could immediately start it back up and run for a short period of time. I think that this is a manifestation of the old characteristic where a battery recovers somewhat when it is off. I also failed to see the annunciator when the battery power was low with my second machine. Fortunately, I also saw the self shut-off feature and remembered that it was time to replace the batteries. Page A-2 of the manual states "... if the battery annunciator is on, and the display dims, you may lose data. ..." It may be that what I saw as a self shutoff was only a dimming of the display. but I returned the machines to operating condition for a short time by pressing ON.

Re: Program Loss in HP-33S Message #4 Posted by Ed Look on 9 Apr 2007, 10:21 p.m., in response to message #3 by Palmer O. Hanson, Jr. Thanks for your replies, John and Palmer. I suppose the RAM clear must have happened when I was not looking. I have this habit of leaving the calculator on to turn itself off after I am through with it for a while... to save the keyboard from "undue" wear and tear. Perhaps it may be better just to switch it off as soon as I am done with it, to reduce chances of something bad happening because it is still powered on. Oh, and the batteries, I believe, are still good.

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