Miscellaneous comments HP41CL - initialization and basic problem solving.
For all HP41CL users: travel may affect your calculator. The HP41CL circuit is quite sensitive to small loses of power, and when being hit while traveling, it may lost part of the programming.
I have used extensively two different HP41CL units. Both of them were sensitive to hits. The faults that could appear were basically two:
The unit would not recognize plugged ROMs. In this case, the solution wasn’t to plug it again, since it wouldn’t work; it was enough to re-enable the memory management using the HP41CL command MMUEN. Then you would find that everything was still where you left it.
The unit would not work well, and get stuck in a strange display. This display would not follow the same pattern always. This was a worse kind of failure, and it always implied to leave the calculator without its batteries for at least 15 minutes, plug the batteries without starting it for another 15 minutes, and then re-start it with backspace-on. You would get a “memory lost” message, and all your programming and configuration would be lost. It will work as a plain HP41CL, but none of the features you bought would be available. You need to re-initialize it. I am sorry for that!
My standard initialization procedure follows here (and this is how my customers receive their calculators):
First clear the memory management unit with the following command:
XEQ Alpha MMUCLR Alpha
Then start loading necessary modules:
Alpha YFNZ Alpha XEQ Alpha PLUG1L Alpha - loading the YFNZ version of the utilities in the lower part of port 1
Alpha PWRL Alpha XEQ Alpha PLUG1U Alpha - loading the PWRL version of the utilities in the upper part of port 1
Alpha 804040–8120 Alpha XEQ Alpha YPOKE Alpha - loading the Library #4
Then, the system is ready to receive any ROM module, including those that use the Library#4 (Basically most of the modules created by Angel Martín)
Then, I usually enter just the Advantage Pac and the latest version of Sandmath that I have in my CL - currently SM33, Sandmath 3x3.