Small cover over toggle keys 41 blanknut

Can anyone tell me why the 41 blanknut has a cover that partially covers the toggle keys on the HP 41 blanknut? Was this present on all blanknuts, or was this an option for certain users to prevent programming input? Also: is it removable without damaging anything (not tat I really need to, just curious.) Thanks,, Theo


Dear Theo, 
Are you talking about the bar disabling USER and PRGM?
If the answer is 'yes', you can easily remove it.
It is sticked, and you can use a slim knife. I did.
I had several Option 001 'Blanknut' HP-41s.
Some had this bar, and some didn't have it.

Yup that's right. I also have had ones without it, and will be getting one in the mail soon that has one, so that made me curious...Thanks for the info! Theo


Dear Theo, 
You are welcome. ;o)
Mine is customized with FORTH41 keyboard.
I almost finished the manual.
Please have a look here
Yours. Mfg.

One of the primary uses for blanknuts was for companies that wanted to run custom applications. With a custom keyboard overlay and ROM module (or a program loaded from magnetic cards), a 41 could be given to a user who knew little or nothing about programmable calculators, but who had been trained to use the custom application. In such a situation the company's support team probably would not want the user turning off USER mode or fooling around with PRGM mode, because that would invite problems. So the USER and PRGM buttons were disabled, and many of the other keys were unlabeled so that users would not be aware that those keys could perform functions other than those labeled on the custom overlay. The calculator always would stay in USER mode and the keys only would perform the functions needed by the company's own special application.


However Synthetic Programming was my solution.
Before I saw that I could remove the bar, I was using register d in order to enable/disable PRGM. ;o)
Regarding USER mode, it was more easy (SF/CF 27).

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