hp 41 (halfnut version)


when was the halfnut manufactured and what is the difference between the halfnut version and the rest of the 41 series


mine is a cx stamped the 44th month of 87 and was sold as the controler for a numericly controled machine tooling unit.


The halfnut version of the 41CV/CX were made in the last 3 to 4 years of the 41 run. Someone here check me if I am wrong, but the halfnut was so named because it was manufactured with half of the componants of the original 41. The PCBs went from 4 to 2 and the chips went from about 4 to 1 or 2. The difference in the 2 was denoted by the black band around the display. Only the halfnut versions had the black band. The halfnut version also had additional features built into its chip to allow for better MCode programing. I hope this helps.


The serial # on my recently-purchased halfnut 41-CV is 2636S21740, placing its manufacture in September 1986. However, text in MOHPC (http://www.hpmuseum.org/collect.htm#earliest) says, "Earliest Halfnut version found: 2511." (March 1985)

Some more info can also be found at http://www.hpmuseum.org/collect.htm#versions


The halfnut machines tend to be more reliable (but less repairable) than the full nut machines. This is becuase they have drastically fewer components and connections than the full nuts (especially that zebra connector between the CPU and keyboard). For harsh field conditions the half nut machines are best.

Full nut displays are much better than the half nut ones. They can be read over a wider viewing angle, have higher contast, and have less temperature dependent variations.

Also full nut keyboards tend to be clickier (both audible and tactile) than the half nut ones. Some people like the softer keys, others like their keys loud and snappy.


Didn't the profile of the keys change along the way? Taller to shorter or vice versa. Was this coincident with the fullnut/halfnut transition?

Possibly Related Threads...
Thread Author Replies Views Last Post
  HP-41(CL): The easiest way to transfer FOCAL programs from a Linux PC to the HP-41 Geir Isene 13 2,588 12-05-2013, 02:40 AM
Last Post: Hans Brueggemann
  HP Prime touch periodic table : new version Mic 4 930 11-25-2013, 05:29 PM
Last Post: Terje Vallestad
  Updated PPC DVD Version 2.10: HP-41 Searchable Program Files and Scannable Barcode Jake Schwartz 3 883 09-27-2013, 09:51 PM
Last Post: Olivier (Wa)
  Where to the 32-bit version of User Code Utiltiy for HP-41 ? Olivier (Wa) 2 691 09-26-2013, 01:55 AM
Last Post: Olivier (Wa)
  HP-11C "horse racing" version Peter Murphy (Livermore) 2 729 08-12-2013, 07:34 PM
Last Post: rpn fan
  Killed my 41-CX Halfnut aj04062 7 1,203 07-10-2012, 07:47 PM
Last Post: Luiz C. Vieira (Brazil)
  HP-41CV "tall keys" version Ignacio Sánchez 16 1,984 06-11-2012, 04:59 AM
Last Post: Diego Díaz
  HP 41CL version 1 and 2, questions Geoff Quickfall 3 678 06-09-2012, 04:18 AM
Last Post: Ángel Martin
  2nd version HP-35 with Finnish manual and back label matti 8 1,288 03-10-2012, 05:34 PM
Last Post: Gerson W. Barbosa
  Scientific version of 30b by HP? kc 26 2,848 02-13-2012, 07:24 PM
Last Post: db (martinez, ca.)

Forum Jump: