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The subject line sums it up. Here is the story:

My 41CX has sat safely on the shelf largely unused for some months, with the Nov-64 in Port 1 and batteries in.

Recently I turned it on, and the keyboard seemed weirdly unresponsive and the display showed a weird display that made me suspect some sort of corruption. Turned off the calc and took out the modules and operation was normal.

I erased the Nov-64 and programmed it anew with just HEPAX. I plugged it back into the CX and turned it on.

This time no funny display. The keyboard does respond and calculator seems to function normally with one exception--there is a latency (delay) of around a second with the pressing of every key. That is, I press the back arrow, I need to hold it for a bit to erase the display. I press Enter, digit, function keys, ALPHA, PRGM, and even OFF, and I need to hold it down for what seems forever before the key does what it is supposed to do.

Apart from this the calculator seems to work fine, even though it takes ages to type anything in because of these delays. The HEPAX functions seem alright and I am able to explore the directories, block assignments, CATs, etc.

With the Nov-64 out of the calculator all behaves normally, including the keyboard.

This is definitely a Nov-64 thing, as when I put the module in my 41CV the behaviour is precisely the same.

I have fresh batteries and there was no problem erasing and reprogramming the module using the most recent Clonix software on a Windows 10 machine.

There was no battery leakage or damage I can see, and, like I said, both 41s behave normally as long as the Nov-64 isn't inserted. Moreover, the module behaves as expected during erasing and reprogramming outside the calc.

But I still wonder--did months of keeping the module and batteries in the unused CXinterfere with how the Nov-64 draws power, the the point that when it is an 41C calculator it interferes with normal keyboard function, but not with how the module is written or read?

I am positively baffled at this and hope I can get some answers and insight.

Many thanks in advance.

Never mind! The contents of a couple of my HEPAX RAM blocks evidently were wonky. Despite the sluggish keyboard, two executions of CLRAM and power cycling the calc. Got everything back in order. Fortunately the programs I had to delete are backed up thanks to PIL-Box, so nothing is lost.

Hope my adventures help someone else.

Thanks for posting that. I haven’t had such troubles with my NoV-64, but it’s good to keep in mind. I actually haven’t used the HEPAX RAM feature. That is non-volatile somehow in that you are able to move the module from one calculator to the other without losing what’s in it? How does that work (it’s not Flash, right?)?
Hi there,

Good to know you managed to get everything back to working condition Les. ;-)

The Non-volatile RAM are not Flash, they use Ferroelectric cells to store info without power.

The memory chips, originally developed by Ramtron Technologies and commonly referred to as FeRAMs, are now part of Cypress Semiconductors' catalog.

In my experience leaving the HP-41 with batteries for several months should be avoided... (yes, we've probably all done that at a given moment...) :-(

Enjoy and best wishes from the Canary Islands.

(12-02-2018 08:24 PM)Diego Diaz Wrote: [ -> ]Enjoy and best wishes from the Canary Islands.

Whereabouts exactly? I see the Clonix41 project involved the Universidad de Las Palmas, so am I right in thinking you're on Gran Canaria? I ask because I've just got home from 10 days over there in the South of the Island (San Fernando, next to Maspalomas) -- who knows, I might have bumped into you at some point Smile

Yes, I'm in Las Palmas de Gran Canaria, though I don't visit the southern coast very often, I've been several times in San Fernando during the 40 years I've been living in here... :-)

Hope you've enjoyed your stay!
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