I have on several occasions noticed that the MMU on the 41CL has been reset upon turning the calc on when I have a NoV-64 plugged in.

Sometimes the time has also been reset.

This does not occur when I do not have the NoV module plugged in.

I suspect a race condition.

I assume that you mean the the MMU has been disabled. This will happen if the POR (power-on-reset) function on the CL board detects that the supply voltage has dropped below a certain value, even if transiently. The Time Module has a similar function built-in, although it operates off of a different supply. The one on the CL board itself monitors the 3.3V supply for the RAM and CPLD. I think that the only way that the POR(s) can be triggered is if the supply dips because of a surge in current drawn while the CL (and NoV-64) is powering up. Since it is affecting both the CL board and the Time module, this suggests to me that the problem is with the I/O block that connects the battery pack to the main board. If this current path is not able to carry the power-up current surge the voltages at the PORs might dip enough to trigger them. So I would check for corrosion/oxidation on the I/O block connections to the battery and the main board.

Monte

I'm really wandering if there is anyone in this world to use the HP-41 for real work. I use it as a number cruncher because of nostalgia.

Isn't nostalgia real work?

Consider the HP-41 as a Glass Bead Game . Then Ángel Martin should be treated as "Magister Ludi".



Cheers

Frido

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Then Ángel Martin should be treated as "Magister Ludi".

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That'd be an honor (Hesse, no less!), and certainly gentler than "The Last Mohican" - though I needn't say that's not true, just check the "What's New" section at TOS to see.

Cheers, ÁM

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I'm really wandering [sic] if there is anyone in this world to use the HP-41 for real work.

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Of course I use HP41 system - and now the more powerfully and much faster 41CL for real world applications : More in detail - I run hardware interfacing and measurement applications with I/O-Board and IL2000 Interface System, which means HP-IL is included to my applications :-)

Best regards - Christoph

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This comes up from time to time. Yes, I use my 41cx every day, because it is functional, not because of any nostalgic value.

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I second that. Twice.

Monte; It is regardless of corrosion (both my CLs does this - and only when the NoV is plugged in. Could it be that since the NoV requires juice, the CL will detect a lack of juice abd disable the MMU?

It may be that there is a current surge on power-up from the NoV that is sufficient to cause the voltage to droop enough to trigger the POR. I suppose that there could also be a transient bus fight between the CL board and the NoV, but the 41CL is designed to force all drivers off until it actually comes out of reset, so I consider this to be unlikely. Does it happen less frequently with new batteries? I am not familiar enough with the NoV design to talk about what kind of current surge there might be.

I have not really noticed any difference with new batteries...

Hi Geir, all,

Late as usual but I'd like to help.

Can you please, mail me with details so I can try to replicate the problem.

Thanks and best wishes.

Diego.