So, I bought a 41CV

[BobVA]

If you don't have the museum DVD's / USB stick they're worth getting for a read through the manual, if a set wasn't included with the one you bought. Very pleasant and it will make sure you don't miss any of the fundamentals about how to program it, etc.

Some quick thoughts:

- The HP-41 uses 1.5 volt "N" (LR1) cells. DO *NOT* INSTALL THE SIMILAR SIZED 12 volt BATTERIES THAT ARE USED IN CIGARETTE LIGHTERS / GARAGE DOOR OPENERS. Many an HP-41 has been lost to that sad mistake.

- You'll notice the keyboard is pretty sparse compared to the 15c. Most of the functions aren't on the keyboard, but are called by typing in their name. If you frequently use a function that's not on the keyboard, you can assign it to any key / shifted key for use with the calculator in "USER" mode. The calculator will accept thin overlays that let you note what the assignments are. And you can hold down a key to see what it does (shows on the display after a second or so). You can assign your own programs to the keys as well, making it very flexible.

- The 41 has a more sophisticated hardware/operating architecture than the 15c (I/O, fully re-assignable keyboard, etc) , but the latter is tuned extremely well to support day-to-day engineering and scientific calculations.

- Right out of the box 41 is extremely capable, and there's an enormous amount of additional documentation available on "under the hood" techniques to further extend it. And the software base for it continues to expand, even today.

- With the right software and peripherals you can do almost anything with the 41 (e.g. make a function specific calculator for the space shuttle or control a data acquisition set up in a lab), whereas the 15c has 90% of what I typically need right on the keyboard. Very different machines designed to solve two achieve two very different goals. Imagine the 15c is the Leatherman tool to the 41's machine shop :-)

You'll have fun with it! If you can get a time module, that adds an interesting dimension to programming and day-to-day use.