This is my attempt to re-initialize a corrupted HP-41CY calculator. If you are not familiar with this device, this project is most probably not for you. Otherwise, please note:
THIS SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, FOR EDUCATIONAL AND NON-COMMERCIAL USE ONLY. USE IT AT YOUR OWN RISK.
Furthermore, I can only provide limited support as I have a life besides HP calculators :-)
If you want to build the ROM images by yourself, please note that the build process is based on my MCODE project setup for macOS. I don't want to repeat the details here.
Unless you don't intend to change the sources, you can just use the ROM images
in subfolder ./rom.
For the re-initialization process you'll need a CLONIX module and an appropriate programmer.
Program a CLONIX module using the following configuration:
| Page | Content |
|---|---|
| #4 | rb2ini-4.rom |
| #8 | Any 4K ROM, e.g., Math |
| #9 | must be empty |
| #A | must be empty |
| #B | rb2ini-b.rom |
| #C | Any 4K ROM, e.g., David Assembler |
| #D | empty (due to CLONIX limitation) |
| #E | Rambx64a.rom (HP-41CY OS/A) |
| #F | Rambx64b.rom (HP-41CY OS/B) |
Prepare your HP-41CY for re-initialization:
- Turn off TURBO mode.
- Make sure that the OS write protection DIP switch is set to Unprotect. You'll find this switch in the battery compartment, see picture below.
- Remove all modules.
- Insert the CLONIX into any port.
Before continuing please note that the whole RAMBOX will be cleared! However, this shouldn't be a problem if your HP-41CY is really corrupted.
Now it's time to turn on your HP-41CY. The re-initialization program starts automatically and shows the following progress:
웃✱✱/a9BCDEF/-bABCDEF-
If not:
- your HP-41CY might be in a state which is not properly handled by this re-initialization module (sorry), or
- there is a hardware problem (ouch).
If you encounter any issues please drop me a note. Maybe it helps to improve this module. Of course, any comments or suggestions are welcome.
For testing purposes I also wrote a HP-41CY Eraser module, see subfolder
./rb2del. This is a take-over ROM, too. When plugged into a HP-41CY it
runs automatically after a power-on and overwrites both banks of the RAMBOX,
including the operating system (if not write protected). Usually, this causes
a severe crash and the calculator goes crazy on the next power-on.
Please refer to the document HP-41CY Technical Information for details about the re-initialization process and some of my findings about the HP-41CY.
You might also be interested in my W&W 32K RAMBOX Initialization ROM.
I guess you already know the following web sites:
- The HP-41 Archive web site contains a lot of interesting information about the HP-41 calculator.
- If you have any questions about HP calculators have a look at the forum on The Museum of HP Calculators. There are many friendly HP calculator enthusiasts that are willing to share their knowledge and experience.
- The CLONIX module is one of the best add-ons you can buy for your Series 41 calculator and worth every penny.