Unabashed CL user promotion or why the 41CL?


Hello all;

This is directed to anyone that knows the 41C family (CX) capabilities and draw backs.

I have a CL (actually 2 now). On the way to Sydney, Australia (a 15 hour leg) on Thursday last week the display faded to non existance on the CL. No big deal as it was a cold solder joint on one of the LCD contacts and easily fixed today.

As a result I could not use the following routines:

Great Circle routine
- data base solutions
- coordinate solutions
Intermediate Latitude
Break scheduler with print functions (very important!)
World time clock
Alarm setting
Stopwatch setting
Temperature corrections
Assorted conversions
Fuel in Tank
Airport door codes (security encrypted)
Phone numbers (PDA)
Metric altitude conversion (data based)

I pulled out my 42S (32K version) and had to plod through with it ;-) It does contain the majority of programs listed but does not contain the convenient data bases which allow for Airport code prompts. I can only say, I could not wait to get home and fix the solder joint on the LCD as the 41CL was sorely missed, especially its ability to do dynamic time functions. The 42S is great but once bitten by the 41 and now the 41CL, I cannot go back

So now to the crux of this story. Basically, why the 41CL?

-the 41CL is fast, very fast, at least, for my programs,
faster then the 42S.
-the display on the 41CL is clear due to the dedicated LCD segments
as opposed to the 42S dot matrix. Much easier to see at night in
low light.
-My CL routines use the dynamic time functions (with module) and
the 42S does not.


-Its ability to be fully 'backup and restore' capable is the big
seller for me.

I removed the batteries today, disassembled the calculator, and repaired the solder joint on the LCD panel. Of course this resulted in Memory Lost but who cares. I did not have to use the tape deck, card reader, HPIL or any other mass storage device.

I simply copied the current HP41CL state back into the Memory
from its flash protected storage registers. It took 15 seconds. The memory transfer included all alarms, extended memory data bases and memory registers. Bang, 15 seconds and all of it back.

Tomorrow over to the Simon Fraser University and in 15 seconds I have my Palynology memory swapped from its on board flash location and then back to work on Friday, 15 seconds later and the calculator is configured for the B777 flight.


I urge anyone using the 41C still to consider the CL upgrade. Unbelievable!!!


Edited: 19 Dec 2011, 2:46 p.m.


Bravo, Geoff! ;)



I am eagerly awaiting my 41CL. According to tracking info it is now in customs, so I am keeping my fingers crossed, though Dutch customs is usuall pretty efficient. Hope to have it before Christmas!

One of my goals is to see how and if I can modify my MLDL2000 software tools to make the functionality work with the 41CL.


Geoff and Meindert, I have had my 41CL for a while and it's a truly amazing machine. I haven't done a lot with it yet as we are in the holiday season, but it is so fast and has so much built into it, I am blown away! I have been reading and re-reading Monte's manual as there is a lot of power built into the Cl-Utils so I am being careful and taking my time. I just printed out the CL-Utils ROM manual and will start reading it too. It will hopefully answer some questions I'm putting together about the 41CL. If not, I will post them here.

I can't stop thanking Monte for such an outstanding upgrade to the HP-41C. Also, a heartfelt thanks to Geoff for his work on my donor 41C. Finally, thanks to you Angel for the manual. I can't wait to start reading it.

So much fun!



Meindert, the MLDL2k works great on the CL - just need to respect the physical addresses so there's no conflicts. Rest assured that both seem to be perfectly compatible.

BTW, the MLDL2k (w/ HEPAX) is the *best* practical method to exchange information between V41 and the real world - all throughout the HEPAX RAM blocks, being "shareable" between both wordls.

Would it be a wild pipe dream to have a future intelligent USB connection that would have a hot-link between both, the real machine and the Windows emulator??



Maybe you could hack it together using PIL-box and a virtual LIF disk? I seem to recall that IL-Per allows concurrent access, but it actually doesn't work.


PIL-BOX & virtual LIF file works great - I did a full sync program between my calendar program on the 41 and Google Calendar/my Android device using the PIL-BOX/EMU41 w/virtual LIF file.


Could you do concurrent access from real and emulated calcs? If you can do that, then you could do development on emu41 (or v41, suitably modified) and automatically download images to the real 41.

Actually, I don't know v41 very well. Perhaps you can write to a LIF image from within it?


Yes, you can do this with EMU41 :)

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