Had to hard reset hp41cx, similar experiences?

[twdeckard]

Had a peculiar, disappointing, experience and I am curious how often others have experienced it?

Faithful (stock) 'cx powered up in an expected state. GRAD mode, several flags set in the display, PROG mode active. Incorrect contents of program memory (although perhaps the program counter was indexed into ROM).

I had to back-arrow power up. I was rather disappointed as I had a large FOCAL program under development and had not updated my notes since making quite a bit of progress.

Its the first time this has happened, has anyone experienced similar? The unit suffers in my backpack and its quite possible it was subjected to a thousand monkey's pushing keys during the course of its rough ride. However, it felt like ESD or some other mystery.

Todd

[Raymond Del Tondo]

(02-24-2018 10:49 PM)twdeckard Wrote:  Had a peculiar, disappointing, experience and I am curious how often others have experienced it?

Back then when I wrote programs on the HP-41 itself in the early 1980ies, I experienced several lock-ups and crashes, so one of the first accessories I bought was a card reader.
When the X-Functions module came out, I bought one of course. However it appeared that X-Memory contents were even more volatile than main memory contents.
Overall system stability of the HP-41 is great, but one of the things I learned early was that data/programs w/o a backup were superfluous:-)

Quote:Its the first time this has happened, has anyone experienced similar?

Don't forget that even the latest HP-41CX units are nearly 30 years old.
Electronic components are prone to age. I have some early HP-41C CPU boards with weak capacitors. These hardly power up on the first go, but after some time with batteries in, they will work fine. Until I remove the batts, of course.

Quote:The unit suffers in my backpack and its quite possible it was subjected to a thousand monkey's pushing keys during the course of its rough ride. However, it felt like ESD or some other mystery.

Given your calc treatment, it seems you just were lucky it didn't happen before;-)

[Joe Horn]

My money is on ESD as the culprit. I've experienced 41CX memory corruption many times when hacking while lying on my bed. The innocent-seeming action of adjusting my position on the bed apparently generated enough static electricity to send the poor 41's memory contents into Tumbolia. Perhaps your backpack is doing something similar? Does using a different calculator case help?

[Garth Wilson]

I got my 41cx Halfnut in 1986. I've never needed a hard reset. and the only crashes I've had were when I was new to synthetic programming and in my inexperience I apparently told it to run off a cliff, to which it responded with "MEMORY LOST" and started clean, ready to go. I've had a couple of programs in my 41 now continuously, without ever reloading, for over 25 years now. Perhaps the Halfnuts are less susceptible to static discharge than the Coconuts were.

[twdeckard]

I have carried a ‘cx in my flight bag since the nineties. There are airport lat/lon’s stored in Ext Memory that I entered twenty years ago. Whenever it comes up after a battery change it makes me smile. I don’t use the DR routines for navigation so the only reason to maintain it is nostalgia.

I am a bit harder on my traveling violin (backup calculator) but I think it was ESD. I am in MN and the relative humidity will be below 25%. I will take more care when pulling it out of the case and see what happens. I’ll also see if it’s of the same vintage as my other unit. Its a working calculator and so I am resigned to the likelihood that it may die with its boots on.

However I really (should) have invested in one of the amazing non volatile storage alternatives or a card reader...I had 200+ registers worth of routines keyed in ...

Best
Todd